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IMS Bearing Replacement - Porsche 911 Carrera
 
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Pelican Technical Article:

IMS Bearing Replacement - Porsche 911 Carrera

Time:

5 hours5 hrs

Tab:

$150 to $600

Talent:

*****

Tools:

Removal, installation, and camshaft timing tools

Applicable Models:

Porsche 996 Carrera models (1999-05)

Parts Required:

IMS Bearing upgrade kit

Hot Tip:

Perform this upgrade when doing a clutch job

Performance Gain:

Years of reliable running

Complementary Modification:

Clutch replacement

Introduction

The M96/M97 Carrera engine has had a checkered past when it comes to reliability (see Pelican Technical Article: Common Engine Problems on the Porsche 911 Carrera). One of the weaknesses identified in recent years by Porsche has been the intermediate shaft bearing (IMS bearing), which supports the intermediate shaft on the flywheel end of the motor (see Figure 6). Porsche designed these motors using a sealed ball bearing that is pressed into the intermediate shaft (Photo 12). These types of bearings are typically used in devices like copy machines and other machinery used in dry conditions. In theory, the area where Porsche designed the bearing to sit is supposed to be dry. However, after years of use within the engine, it would appear that oil and contaminants from the engine seep past the bearing seal, wash out the original lubricant, and become trapped inside. The result is that the bearing now operates in a less-than-ideal environment and begins to wear prematurely. When the bearing wears out, the timing chains on the engine may disengage, and the engine will quickly self-destruct. When the bearing does begin to deteriorate, foreign object debris from the bearing circulates throughout the engine, causing damage to other areas in the engine. This appears to be one of the most common failure mechanisms present with both the Boxster and 911 Carrera engine.

The center bolt that holds the entire assembly can also fail. If this bolt breaks, it will immediately allow the intermediate shaft to float, and the engine will skip timing. This will result in the complete destruction of the engine in a very short period of time (seconds). Typically, a deteriorating intermediate shaft bearing will also cause the center stud to weaken and break. The stud has a groove cut into it axially to allow for a sealing O-ring to seal to the outer cover. This groove causes a stress concentration to occur and promotes the failure of the stud. The solution is to pull out the bearing and replace the stud with a new one that is stronger and manufactured without any grooves (see a comparison of the old and new studs in Figure 5).

So how do you know if you have a problem? There are several warning signs. When you first start your car, you may hear a loud rattling noise that goes away after about 10 seconds or so. When you accelerate, you may also hear this noise too. This noise is the sound of the chains or the bearing rattling around in the engine because the bearing has deteriorated--the engine is soon on its way to skipping a tooth on the sprocket and costing you thousands of dollars. To detect the early stages of a failure, listen for a sound that is similar to what a throw-out bearing, water pump, or a belt idler pulley sounds like when the ball bearings begin to fail. If you have the car up in the air and running, you can listen carefully and you should be able to isolate the noise to the area of the IMS bearing (bottom rear of the engine, near where it mounts to the transmission), especially if you use a diagnostic stethoscope.

Signs of a failing IMS bearing can also be found by inspecting the oil filter. Shiny metallic debris from the balls used within the bearing itself may travel through the oil system and become trapped in the oil filter as well as small bits of black plastic from the seal on the bearing (see Figure 1). During a routine clutch job, you can also simply remove the IMS cover and take a closer look at the bearing itself (lock and check the camshafts prior to removing the cover though--see instructions below). If the center shaft is wobbly, or the center of the bearing doesn't spin freely, then it's probably on its way to failure.

Another way to check the engine is with the factory PST-2 tool, or the Durametric tool (see Pelican Technical Article: Reading Porsche 911 Carrera Fuel Injection Fault Codes). You can compare the deviations in the timing between the two camshafts to see if they vary widely, particularly when revving the engine (see Figure 2). Sometimes a failing IMS bearing will also trigger a "check engine light" warning on your dash, as the car's computer realizes that there is a significant deviation between the two camshaft readings.

What Does a Bearing Failure Look Like?

If you take a look at Figure 1, you will see the remains of an intermediate shaft bearing from an engine with only 31,000 miles on it. Pulling off the intermediate shaft bearing cover revealed that the bearing had completely disintegrated and there wasn't much left. This engine was running and the car was driving, but every few seconds it would make a horrible screeching noise. Sometimes it would run for quite a few minutes with no sound at all. Hard to believe, considering that the bearing was completely destroyed.

So what can you do with an engine that has had this much bearing damage? The engine was still running when I took the bearing out, so I know there didn't appear to be any damage to the cylinder heads from the timing chains being out of sync. The oil filter appeared to do its job of blocking most of the bearing debris in the oil. The only thing that you can do when you have a situation like this is to clean everything out very carefully, replace the bearing, and button the engine back up.

What Can be Done to Fix or Prevent a Failure?

Luckily, there are a few solutions available. Firstly, I recommend that you change your oil every 5,000 miles or sooner and use a higher viscosity motor oil that has additional anti-wear additives. Use Porsche approved 5w40 viscosity motor oils, preferably one that carries an API SJ-SL rating. Use of a 0w40 viscosity should be limited to colder climates in winter months, where cold starts are regularly below freezing, for added start up protection. Also consider using an oil with more anti-wear additives (like Zn, P, or moly extreme). Recent regulatory changes in the United States have caused oil companies to revise their formulations of oil and reduce the amount of anti-wear components in them. The reasoning behind this is the belief that these components contribute to premature deterioration of the catalytic converters. I'm not so sure I agree with that premise however. The solution to this problem is to make sure that you run motor oil with the proper anti-wear formulations and change your oil often.

Also curious is the fact that cars that are driven tamely seem to have more problems than cars that are driven aggressively. 911 Carrera engines that are used at the track are known to have very few problems relating to the bearing, whereas 911s driven by "little old ladies" tend to show the most damage. The track-day Carrera bearing longevity may be explained by the fact that these cars often have their oil changed after every trip to the track.

The best solution to the problem is to replace the bearing prior to its failure. Porsche Club of America tech advisor Scott Slauson from Softronic (see Pelican Technical Article: Updating Your DME with Performance Software for the Porsche 911 Carrera) pioneered a procedure that allows you to replace the bearing with the engine still in the car. Building upon that procedure, LN Engineering and Pelican Parts have both developed bearing replacement kits to swap out the troublesome original bearing.

Which Bearing is Inside Your Engine?

The first step in replacing the bearing is to figure out which one you have in your engine. There were three variations installed over the years. Early cars typically have a large double row bearing that has a snap clip inside the bearing. Porsche later went to a single-row bearing design when the timing chain design was modified (see Figure 7 for a comparison of the two). Then, around model year 2006, Porsche installed a third version that is not replaceable. The supposed cut-off on engine numbers is listed in the Porsche factory Technical Bulletins, but unfortunately, these numbers are not 100 percent accurate, so you need to look at the bearing housing on your engine in order to be 100 percent sure as to which bearing you have installed.

Porsche's electronic parts catalog lists the following engine numbers as the cutoffs for the various engines:

Up to engine # M 661 141164, Carrera 996 3.4-liter

From engine # M 661 141165, Carrera 996 3.4-liter

However, as mentioned previously, practical experience has determined that these numbers are not 100 percent correct. Porsche replaced and/or repaired a lot of engines over the years, and as a result there are a lot of engines out there where parts are mixed and matched. For example, the 3.4 Porsche factory motor that I installed in my 3.4-liter conversion has the very-late-style intermediate shaft bearing with the 22mm center nut (see Photo 15), but is missing some other upgrades that had been implemented over the years.

The only way to know certainly is to remove your transmission and look. The double-row version of the intermediate shaft was the first version used on these engines and will almost always be found on the early cars. The intermediate shaft cover for the double-row bearing is characterized by a shallow dish; the single-row bearings have a much deeper dish, as shown in Figure 7.

Pelican Parts Replacement Kit

The Pelican Parts intermediate shaft bearing replacement kit is shown in Figure 3 and contains everything that you need to perform the replacement in either a single- or dual-row bearing engine. The Pelican kit uses the same bearing that Porsche used when originally building the engines, but the kit incorporates a stronger seal on the outside of the bearing. The kit is designed so that the bearing replacement can be performed during a routine clutch replacement (see Pelican Technical Article: Clutch Replacement on the Porsche 911 Carrera). Changing out the bearing during each clutch job will ensure that the bearing is fresh and not wearing prematurely. As stated in the previous section, the failure mode of this bearing is not well known--if it's swapped out and replaced every 30,000-45,000 miles when the clutch is renewed, it should protect your engine from problems.

The kit uses a single-row bearing, just like the later-style Porsche design. For engines that originally had a double-row bearing installed, there are two spacers included with the kit (Figure 4). These spacers fill the space that was normally occupied by the double-row bearing. In addition to the bearing replacement, the kit also includes a stronger center stud. Instead of having the O-ring integrated into the stud, the O-ring is placed in a V-shaped sandwich on the outside surface of the bearing housing cover. The Pelican kit is available online at Pelican Parts.com.

LN Engineering Retrofit Kit

The LN Engineering IMS Retrofit kit is also an easy-to-install upgrade kit that can be installed with the engine still in the car and provides almost bulletproof reliability to this critical component. This kit costs about $600 and is available online from PelicanParts.com. The upgrade kit incorporates a custom ceramic hybrid bearing (see Figure 5), featuring precision Japanese-made tool steel races and genuine USA-made Timken sintered silicon nitride ultra-low friction roller balls. This bearing, combined with a beefier center stud and a custom-machined housing, ensures that the IMS problems inherent in the stock design are mitigated. The engine can be upgraded during a routine clutch job and is fairly easy to install thanks to the installation tools designed by LN Engineering specifically for this task.

Which Kit to Use?

I designed the Pelican Parts replacement bearing kit in order to fill a gap within the do-it-yourself (DIY) market. This kit is designed to replace the factory bearing with a very similarly manufactured bearing (with an improved seal and updated center bolt). I recommend that the bearing be swapped out each time a clutch replacement is performed (30,000-45,000 miles). The outer seal is not removed on the kit, instead an improved seal is installed, which should offer longer life than the factory original. Replacement bearings, O-rings, and parts will be available for customers who have already performed the swap at least once and already have the tools, spacers, and the improved center bolt. The Pelican Parts kit uses the stock intermediate shaft bearing cover as a way to reduce the total cost of the kit, though we recommend if you have the older style single round gasket cover you replace this with the newer version from Porsche which is less likely leak. While we include both style of gaskets in the kit including a replacement gasket for the older style covers, Porsche no longer supports this part.

The LN Engineering retrofit kit contains a stronger-than-stock center stud, a custom machined intermediate shaft end cover, and a special, custom-manufactured ceramic bearing, which is very expensive, but has much longer life under harsh conditions. The LN Engineering kit is considered to be the more robust kit and is designed primarily for shops that are installing the retrofit and need that extra guarantee for their customers. The extended-life ceramic bearing (see Figure 5) is only available at this time with the LN Engineering kit, and its inclusion is responsible for a large portion of the cost difference between the two kits.

Bearing Removal

The bearing is located behind the flywheel of the engine, so the first step that you need to do is jack up the car (see Pelican Technical Article: Jacking Up Your Porsche 911 Carrera) and remove the transmission (see Pelican Technical Article: Transmission Removal - Porsche 911 Carrera). Then, remove the clutch and flywheel from the engine (see Pelican Technical Article: Clutch Replacement on the Porsche 911 Carrera). With the car elevated in the air, drain the oil out and remove and inspect the oil filter (see Pelican Technical Article: Jacking Up Your Porsche 911 Carrera).

Before doing anything else, you want to remove the camshaft end plugs from your engine (see Figure 2 of Pelican Technical Article: Porsche 911 Carrera Camshaft Swap and Valve Train Repair). While it is a very tight fit doing this with the engine n the car, it is doable if you take your time. These plugs cover the camshaft timing marks--you will need to check the timing on the camshafts when you are done with your bearing replacement. If you have a pre-2002 engine, then you only need to remove the plugs on the exhaust camshafts (two plugs total). The exhaust camshafts are located on the bottom of the engine. If you have a 2002 or later engine, then you need to remove all four plugs (intake and exhaust), because you will need to check all four camshafts when you are done. While it is a tight fit doing this with the engine in the car, it is doable if you take your time. For the 911 Carrera, the plugs for the camshafts that drive cylinders 4-6 should be easily accessible at the front of the engine to the right of the flywheel area. The plugs for cylinders 1-3 need can be accessed from the back of the engine by the exhaust.

With the plugs removed, now remove the three bolts that hold on the intermediate shaft bearing cover (Figure 9). With the bolts removed, you should be able to shine a flashlight down the holes and see the intermediate shaft sprocket inside the engine (Photo 10). What you are looking at is the big sprocket for the intermediate shaft, as shown in Figure 5. What you want to do is rotate the engine clockwise until you can find three spots behind these through holes where the metal surface of sprocket is blocking the holes. You may find it easier to rotate the engine if you remove the spark plugs (Pelican Technical Article: Replacing Spark Plugs on your Porsche 911 Carrera). You will then insert set screws into these holes and push the screw into the sprocket in order to hold it in place while you're performing the bearing replacement (see Photo 12). Rotate the engine until you have found a spot where all three holes are blocked, then install the set screws. Tighten the screws down only hand-tight, but very snug, using a small tool or ratchet. Don't use the iron grip of death here, as you don't want to strip out the small M6 bolts. Just make them very snug and tight with your hand.

With the intermediate shaft sprocket locked in place by the set screws, now is the time that you want to mark the locations of your camshafts. Again, you only need to mark the two exhaust camshafts on the pre-2002 engines. This is because the intake and exhaust camshafts are tied together with a chain of their own, and if one is properly set, then the other is properly set as well (see Photo 22 for more clarification). If you have a 2002 and later Carrera engine, this particular design uses what are known as vane-cell adjusters and a single chain to link both the exhaust and intake camshafts together (see Photo 22). This design has a tendency to have the camshafts slip when performing the replacement, so you need to be vigilant in checking all four camshafts (see the section on checking camshafts at the end of this project).

Use some marking paint or a scribe to mark the locations of the camshaft with respect to the cylinder head (see Photo 13). Make sure that the marks are clear and visible--you will be rotating the engine 360 degrees when you are done to verify that all of the camshafts line up again with the marks that you created.

With the camshaft timing properly marked and the intermediate shaft secured, it's time to remove the two tensioners that pull on the flywheel-end sprockets of the intermediate shaft. The first one to remove is the tensioner located to the right of the flywheel area. Next, remove the tensioner that tightens the chain that connects the intermediate shaft to the crankshaft, located to the right of the flywheel area (Photo 14). Be sure to have an oil catch pan ready when you remove these two tensioners, as oil will spill out.

Next, remove the center nut from the bearing. I have found that these typically just come off with a 13mm socket, but you may have to use an open 13mm wrench and a screwdriver to hold the center of the bolt as you remove the nut. With the center nut removed, you should be able to slightly tap the cover counterclockwise so that you can get some pry bars underneath (Photo 15). You will need at least two of them to get the cover off (one just won't work), applying pressure in two places at the same time. There is a special tool available from Porsche to assist in removing the cover, but it's quite expensive and not really necessary.

With the cover removed, you should be able to see the bearing underneath. The inset of Figure 9 shows an example of a completely destroyed IMS bearing, and Photo 12 shows more of what a normal bearing should look like. If you accidentally drop the center bolt into the recesses of the intermediate shaft, then simply pluck it out with a magnetic tool. If you have a single-row bearing engine, at this point you will want to remove the large circlip that holds the bearing in place (see Photo 19). If you have a double-row bearing engine, then the internal snap ring will simply snap out automatically when you go to pull the bearing.

There is a specialized bearing removal tool that was developed by the folks at LN Engineering for this task (Photo 16). Thread the center bar of the tool onto the bearing stud and turn it so it threads all the way down to the base of the bearing (inset of Photo 16). Slide the removal tool canister over the threaded rod and then screw on the large nut that fits on the threaded rod. Apply some motor oil to the nut and the back surface of the tool to ease the removal process. With the tool in place, hold the threaded rod and turn the nut clockwise to remove the bearing. Be sure to wear safety glasses, as the tool applies a lot of force to pull the bearing out of the engine. Turn the wrench on the nut until the bearing slides out of the engine. For engines with a dual-row bearing, you will hear a loud pop when the internal snap ring pops out of its groove. Be sure to have an oil catch pan or a bucket handy, as a significant amount of oil will most likely exit out of the intermediate shaft bore when you remove the bearing.

Inside the intermediate shaft you will most likely find some oil and debris. Get some paper towels and tape them to the end of a stick and clean out the inside of the intermediate shaft. You can also attach a small rubber hose to the end of your shop vacuum and suck out any debris that might remain in there.

There's a small possibility that your bearing center stud may break when attempting to pull the bearing out of the engine. If this happens, then you need to remove the bearing using an internal bearing puller tool (like the Stahlwille puller shown on 101Projects.com).

Bearing Installation

If your bearing and center stud did not come pressed together, begin by taking the bearing over to your table vice to press in the center stud. Press in the center stud, taking care only to apply pressing force to the inside bearing race. You can use a regular socket from your toolbox to accomplish this. It does not matter which side of the bearing faces the center stud. See the inset of Photo 17 for more details.

Prior to installing the new bearing, verify that your intermediate shaft bore is completely clean and free of debris. Using the bearing installation tool, place the new bearing/stud assembly into the end of the tool. The tool is designed to hold and constrain the bearing while you install it--you need to push the 12mm nut down the shaft of the tool and spin it onto the center stud's threads.

Prepare for the installation of the new bearing by placing it along with the installation tool in your freezer overnight. The cold temperatures will help shrink the bearing races and make it easier to install. This is an old trick that is commonly used when installing wheel bearings.

With the bearing and tool assembly combined tightly together, place the bearing into the bore on the intermediate shaft (Photo 17). Verify that the placement of the bearing is completely centered and square to the plane of the engine case (make sure it's not cocked off in any direction, even slightly. With a plastic hammer, carefully tap the bearing into place. It should go in relatively smoothly and without too much effort.

If you are performing the installation on an engine that uses a double-row bearing, install the outer spacer into the bore as is shown in Photo 18. Then, proceed to install the Spiroloc clip into the groove in the intermediate shaft (inset Photo 19). When the clip is completely installed into the engine, you can then install the intermediate shaft bearing cover in place. Take the smaller spacer and place it on the backside cover. Then place the cover on the engine and tap it into place using a small rubber hammer (Photo 20).

If you are performing the installation on an engine that uses a single-row bearing, then you don't need to install any spacers--just simply install the big circlip as shown in Photo 19, and then install the intermediate shaft cover as is shown in Photo 20. With both single- and double-row installations, you will want to use a new seal on the cover. If your cover is the older-style one with the small black O-ring, you will want to upgrade to the newer-style cover and improved seal to guard against leaks. I also like to place a small bit of Curil-T sealant on this seal when I'm installing it, just as an added measure of oil-leak protection. The cover can only go on in one orientation--typically the numbers/writing on the later-style covers goes at the bottom. When installing the cover, be careful not to pinch or damage the seal, as it has a tendency to get caught sometimes during the installation process.

If for some reason you are having difficulty driving the intermediate shaft cover into place, then you can use the following procedure to assist you. Use three M6x25 bolts (included in the Pelican Parts Kit) to help guide the cover into place. Place the cover into the bore and tap it down as far as it will go. Then, remove the set screws that you placed earlier (Photo 11). Install the bolts, and then crank each one down in an alternating pattern until the cover is flush with the engine case. When the cover is installed in place, then remove the three M6x25 bolts.

With the cover fully in place, you can now remove the set screws. Replace them with new micro-encapsulated bolts included in the Pelican Parts kit (inset Photo 21). The phrase "micro-encapsulated" is a fancy word for bolts that have some sealant on them. It's okay to reuse your old bolts, but be sure that you coat the threads in a sealant like Curil-T or Loctite prior to installation or they will leak. Tighten the bolts down to 8 ft-lbs (11 Nm).

With the cover installed and the cover bolts tightened down and sealed, install the O-ring on the center shaft (Photo 20). I recommend putting a thin layer of Curil-T sealant around this O-ring in order to help seal against leaks. With the O-ring in place, now install the spacer. Finally, install the 12-point nut on the top, tightening it to a maximum of 24 ft-lbs. I also recommend placing a bit of Curil-T sealant underneath this nut.

If you are installing the LN Engineering retrofit kit, then the procedure is almost identical, if not simpler. Install the new intermediate shaft bearing cover in the same manner as described above. Prior to installation, verify that the O-ring that fits in the center of the shaft is in place and undamaged. Install the 12-point nut on the end using some green Loctite flange sealant as an added protection against leaks. Photo 21 shows the LN Engineering ceramic bearing installed in the case with the open no-seal side facing outwards, and the inset shows the retrofit kit intermediate shaft end cover installed in place.

At this time I also recommend that you replace your rear main seal (RMS) with the new, updated version. See Project 44 for more details.

Checking Camshaft Timing

With the new bearing installed in place, you are basically done with the installation. However, it's very important that you check your camshaft timing prior to reinstalling the transmission and starting the engine. Photo 22 shows how the timing chains are oriented and setup on the five-chain (996 Carrera thru 2001) and three-chain motors (996/997 Carrera 2002 and later). Particularly with the three-chain motors, you need to make sure that you check the exhaust camshaft for cylinders 1-3 (located to the right of the flywheel). This particular camshaft has the least amount of chain wrap, and removing the chain tensioner to perform the replacement has the potential to loosen the chain and allow the timing to skip a tooth on the sprocket.

To check the timing simply take the crankshaft and rotate it 360 degrees from where you originally placed it when you installed the set screws. Then check the marks that you made on the camshafts (four marks on all four camshafts for the three-chain motors, two marks on the exhaust camshafts for the five-chain motors). If all of the marks line up perfectly, then you're golden, and you can continue on with finishing up the installation. If any of the marks are off, then there is the potential that the timing chain slipped off of the camshaft sprocket during the installation process. See Project 16 for more information on retiming the camshafts if this happens.

If you happen to have the P253 camshaft timing tool, you can use that to check the timing on the five-chain engines. Simply place the engine at top dead center (see Figure 1 of Pelican Technical Article: Porsche 911 Carrera Camshaft Swap and Valve Train Repair), remove all four green caps on the camshafts, and install the tool on each side to check each pair of camshafts (see Figure 3 of Pelican Technical Article: Porsche 911 Carrera Camshaft Swap and Valve Train Repair). If the tool fits, then the timing is perfect. If it doesn't fit, then you will have to retime the cams (see Pelican Technical Article: Porsche 911 Carrera Camshaft Swap and Valve Train Repair). It's very good practice to check the timing on the five-chain motors, but in reality, very few of these have problems, unless the instructions were not followed correctly. Still, I recommend checking the timing prior to reinstalling the transmission--it's cheap insurance.

After you're done checking the camshafts, install new camshaft end caps as shown in Photo 27 of Pelican Technical Article: Porsche 911 Carrera Camshaft Swap and Valve Train Repair. Although I like to use a bit of sealant everywhere, these end caps don't tend to leak.

Also important to note, if you have the camshaft tools handy, you might want to check your camshaft timing prior to beginning the installation of the bearing. If the timing is slightly off and the bearing appears fine, then you might have some additional problems in your camshaft timing chain mechanism (slipping sprockets on the intermediate shafts, worn pads on the camshaft solenoid mechanisms, etc.). I would advise investigating these problems prior to pulling out the bearing.

Don't forget to change the filter and add oil! See Project 2 for more details. If you pulled your bearing and found some major wear or damage, then you probably want to pull the bottom sump off and clean it out (see Pelican Technical Article: Installing a Deep Sump Kit - Porsche 911). Also think seriously about replacing your sump air-oil separators, as they tend to get contaminated, too, if you have bearing debris in your sump.

If you check the official website for the book, you will find more reference photos for this project, along with a complete list of part numbers of all of the parts used in this project (see http://www.101Projects.com/Carrera/14.htm).

Here are the remains of a destroyed IMS bearing after we removed it from our M96 engine.
Figure 1

Here are the remains of a destroyed IMS bearing after we removed it from our M96 engine. It fell apart in my hand taking it out of the removal tool. We still didn't find the remains of one of the bearing rubber seals anywhere. Sometimes you can see the signs of an intermediate shaft bearing failure. The upper left inset shows what the oil filter looked like when we removed it from our engine. You can clearly see small flakes of metal in the filter. It looks like the filter did a pretty good job of blocking the particles--since this was caught in time, we anticipate that the engine should be fine. Lots of debris ended up getting caught in the oil sump and pickup screen, which is a good thing. If your bearing is trashed when you remove it, be sure to pull the sump off the bottom of the engine, clean it out thoroughly, and replace the two air-oil separators located in the sump area (see Pelican Technical Article: Installing a Deep Sump Kit - Porsche 911).

Sometimes you can detect a failing intermediate shaft bearing by running a test showing camshaft deviations.
Figure 2

Sometimes you can detect a failing intermediate shaft bearing by running a test showing camshaft deviations. Using the Durametric tool, or a PST-2, you can setup the screen to log camshaft deviation as a function of ignition timing and rpm. Significant variations between the left and right camshaft banks can be an indicator of trouble with the bearing. In this graph, the deviation is zero, which is perfect and does not indicate a problem.

This photo shows the parts contained in the Pelican Parts Intermediate Shaft Bearing Replacement Kit: A: Improved center bearing bolt, replacement intermediate shaft bearing, center bolt O-ring, center bolt nut.
Figure 3

This photo shows the parts contained in the Pelican Parts Intermediate Shaft Bearing Replacement Kit: A: Improved center bearing bolt, replacement intermediate shaft bearing, center bolt O-ring, center bolt nut. B: Updated 3-groove flange seal. C: O-ring for older style flange seal. D: 3 new micro-encapsulated cover bolts. E: Spiroloc snap ring (for engine with double-row bearings).F: Snap ring (for engine with single-row bearings. G: Outer race spacer (for engine with double-row bearings). H: 3 M6x25mm installation helper bolts. I: Inner race spacer (for engine with double row bearings. J: 3 M6x1x25mm set screws. K: Short center bolt spacer (for engine with double-row bearings), L: Long center bolt spacer (for engine with single-row bearing).

Here are two sides view of the Pelican replacement kitÃÆ'¢Ã¢‚¬
Figure 4

Here are two sides view of the Pelican replacement kit--double-row configuration shown on the left with the spacers in place, single-row on the right. These covers have the updated brown seal (see Figure 8).

This photo array shows the various elements that comprise the LN Engineering upgrade kit for the intermediate shaft bearing.
Figure 5

This photo array shows the various elements that comprise the LN Engineering upgrade kit for the intermediate shaft bearing. A: This is a version of the retrofit kit that is installed during the rebuild process and requires the engine be apart. B: The improved ceramic coated ball bearing. C: Stronger center bolt (left) when compared to the thinner and weaker OEM shoulder bolt (right). D: Upgrade kit for early engines with the double-row bearing. E: Upgrade kit for the later engines with the single row bearing.

Here's a neat side/cutaway view of the intermediate shaft and the LN Engineering IMS retrofit kit installed.
Figure 6

Here's a neat side/cutaway view of the intermediate shaft and the LN Engineering IMS retrofit kit installed. This photo shows the intermediate shaft upgrade kit installed into a display engine with one half of the engine case missing. Shown here are the intermediate shaft timing chain (blue arrow), the intermediate shaft gear (yellow arrow), the intermediate shaft bearing cover/housing (red arrow), the housing-to-crankcase seal (orange arrow), one of the three bolts that attach the housing to the case (purple arrow), and the engine case (white arrow). The bearing stud and nut are also shown installed in the center of the housing.

Shown here are two late-style intermediate shaft covers.
Figure 7

Shown here are two late-style intermediate shaft covers. The cover on the left has a deep dish and is used in engines that originally had a single-row bearing. The cover on the right is shallower and is used with engines that originally had a double-row bearing. Unfortunately, the records on which engine used which style of bearing is very spotty, so the only real way you can tell is by removing the transmission and seeing what you have installed in there.

The top portion of this photo shows the troublesome O-ring that was found on the early intermediate shaft bearing covers.
Figure 8

The top portion of this photo shows the troublesome O-ring that was found on the early intermediate shaft bearing covers. The bottom shows a close-up photograph of the improved three-ridge seal. If you pull off your intermediate shaft cover and you find that you have the early style, then I highly recommend that you upgrade to this later-style cover.

It all starts here with the intermediate shaft cover, located right under the rear main seal (located behind the clutch and flywheel).
Figure 9

It all starts here with the intermediate shaft cover, located right under the rear main seal (located behind the clutch and flywheel). Using a 10mm socket, remove the three bolts that hold on the intermediate shaft cover. There's quite a bit of oil residue on the lower half of the cover, which seems to indicate that there is some leakage from the seal. The inset photo shows a completely destroyed intermediate shaft bearing (IMS). The outer seal and race are missing. The balls have fallen down in the bearing and are basically just sitting there. This engine was very close to self-destructing: it was wise for the owner to turn it off and not drive it any more. As a result, he may have saved the engine from complete destruction. However, the remains of the bearing have circulated out of this area and down to the engine sump: if any metallic particles got past the filter, then they would have caused damage to the rest of the engine (bearings, etc.).

The holes that hold on the intermediate shaft cover are through-holes, which means they exit out into the engine case.
Figure 10

The holes that hold on the intermediate shaft cover are through-holes, which means they exit out into the engine case. With the cover bolts removed, rotate the crankshaft until you see metal appear behind each of these holes. The intermediate shaft has some large relief holes cut in the big sprocket (see Figure 6). You want to rotate the engine until all of the small little holes here are blocked by metal on the sprocket. This way, none of the set screws will go into one of the larger holes on the sprocket. When you install the set screws, they should firm up just below the surface of the case. If they don't then make sure you don't keep turning them: you may end up dropping them into your engine case, which will make them very difficult to retrieve later on.

After you've lined up the gear behind the cover, insert the set screws into the holes and tighten them down.
Figure 11

After you've lined up the gear behind the cover, insert the set screws into the holes and tighten them down. Don't use the iron-grip-of-death to tighten them down, they only need to be hand-tight. With the set screws in place, you should be able to tap the cover and rotate it back and forth in its bore a bit. The inset photo shows a close-up of the DIN916 M6 1.00 x 25 length set screws included in the Pelican Parts kit that fit perfectly for this task.

The yellow arrow shows how the set screw pushes against the sprocket surface and holds it in place.
Figure 12

The yellow arrow shows how the set screw pushes against the sprocket surface and holds it in place. When you're rotating the engine, you want all three set screws to be pushing on the surface of the sprocket, not pushing through one of the open holes (green arrow). Here's another photo of the right side showing how the set screws secure the shaft in place. The screws act just as a friction fit to keep the shaft from moving or rotating while you're working on it.

With the set screws in place, mark the camshafts with some marking ink or paint.
Figure 13

With the set screws in place, mark the camshafts with some marking ink or paint. Mark the two intake camshafts for pre-2003 engines, and mark all four for 2003 and later engines. The pre-2003 engines had the intake and exhaust camshafts tied together with a separate chain, so if one camshaft is properly timed, then the other one should be as well. You want to mark the camshafts to make sure that they do not move or rotate while you're doing the installation and alter the timing of the engine. When you're done with the installation, you will rotate the engine 360 degrees and double-check to make sure these marks all line up again perfectly.

You need to release a bit of the tension on the camshaft chains by unscrewing the tensioners out of their bore.
Figure 14

You need to release a bit of the tension on the camshaft chains by unscrewing the tensioners out of their bore. Use a wrench to release the primary chain tensioner located inside the engine block, next to the flywheel (shown on the left). This chain tensioner tightens the chain that connects the intermediate shaft to the crankshaft. In a similar manner, loosen up the chain tensioner for cylinders Picture 3:, which is located inside the bottom of the Picture 3: cylinder head (shown on the right, and located on the left side of the car). The yellow arrow points to the aluminum sealing ring which should be replaced when you reinstall the tensioner.

This photo shows the intermediate shaft cover/housing with the three bolts removed and the center nut disconnected.
Figure 15

This photo shows the intermediate shaft cover/housing with the three bolts removed and the center nut disconnected. Use two small pry bars to remove the cover from the engine. The cover shown installed in this engine is a shallow one, meaning that this engine has a double-row bearing inside. The inset photo in the upper right shows a stock cover for a single-row bearing--notice how the inside cone of the cover is deeper. The inset in the upper left shows the 2006-later-style intermediate shaft cover with the larger nut. The bearings behind this cover are non-replaceable because the bearing is physically constrained by the engine case.

Install the bearing removal tool onto the center stud by threading the center rod piece onto the center bolt that holds the bearing and the cover plate together (inset photo).
Figure 16

Install the bearing removal tool onto the center stud by threading the center rod piece onto the center bolt that holds the bearing and the cover plate together (inset photo). Make sure that you thread the hexagon shaped piece down as far as it can go onto the bolt. Slide on the outer cylinder and spin on the nut to the threaded rod. I found it most useful to lubricate the back surface of the cylinder and the nut, too, in order to facilitate easier turning of the nut. With a 24mm wrench and a breaker bar/13mm socket combo, hold the center shaft in place (green arrow) while turning the wrench clockwise (yellow arrow). This will slowly pull the IMS bearing out of the bore of the intermediate shaft. For the double-row bearings, you will need to apply quite a lot of force. You will also hear a loud "POP" sound as the retaining ring snaps out of place. After this pop, the amount of force to remove and pull out the bearing should be moderate.

If the center bolt is not pre-installed into the bearing, you need to gently press it in.
Figure 17

If the center bolt is not pre-installed into the bearing, you need to gently press it in. Place an appropriately sized socket against the inner race of the bearing and then press the bolt in using a vice (upper right inset photo). Be sure that the socket only presses on the inner race of the bearing. This will assure when you press in the bearing that any force used is applied only to the inner race of the bearing. Applying force to the outside race of the bearing when pressing can damage the bearing and shorten its life. You can press in the center stud and then place the entire assembly into your freezer (inset upper left). This trick is commonly used with wheel bearings and shrinks the outer race just slightly when you install it, allowing you to use much less force during the installation. You want to place as little force as possible on the intermediate shaft because you don't want to knock it loose from where it's being held in place by the set screws. Using a hammer with a plastic head, carefully tap the end of the installation tool. With the bearing cold from the freezer, it should not require a tremendous amount of force to install. Tap the bearing in using the tool until it's seated against the back of its bore in the intermediate shaft.

Here's the bearing shown installed in the bore of the intermediate shaft with the outer spacer in place (yellow arrow).
Figure 18

Here's the bearing shown installed in the bore of the intermediate shaft with the outer spacer in place (yellow arrow). This is an engine that used the double-row bearing. The inset photo in the upper left shows the improved center bearing bolt. This bolt is much stronger than the original and does not suffer from any weak points like the original Porsche design. The lower left inset photos shows the long center bolt spacer for engines with single-row bearings. The secret to keeping oil from leaking out of the bearing assembly lies with the V-groove precision-machined into the spacer. This design squeezes the O-ring tightly against the intermediate shaft cover plate and the bolt, creating a leak-resistance seal. This design element is very similar to the V-groove washers used on the case through-bolts that are installed in the 1965-1989 Porsche 911 air-cooled engines.

For engines with the single-row bearing, the bearing is held in place against the intermediate shaft by a big circlip.
Figure 19

For engines with the single-row bearing, the bearing is held in place against the intermediate shaft by a big circlip. Using a set of circlip pliers, remove this clip before pulling the bearing, and place it back into its groove after the new bearing is installed. For engines that use the double-row bearing, you install the new bearing, the spacer, and then the Spiroloc circlip (inset photo). Thread the clip into the groove and then rotate it to install it in place.

A: With the bearing, the large outer spacer, and the Spiroloc installed, it's time to install the bearing cover along with the smaller spacer (double-row only).
Figure 20

A: With the bearing, the large outer spacer, and the Spiroloc installed, it's time to install the bearing cover along with the smaller spacer (double-row only). Place the small spacer on the bearing cover as shown by the yellow arrow. If you are reinstalling the bearing cover with the later-style improved seal, I recommend using a new one. B: Use the longer M6 x 25 helper bolts contained in the pelican Parts kit to help seat the cover. Then remove the helper bolts and use the new bolts to tighten down the cover. Torque to a maximum of 8 ft-lbs (11 Nm). If you're not using new bolts, then be sure that you coat the threads with a liberal amount of sealant so they won't leak. With the cover in place, slide on the O-ring as shown. I recommend coating the O-ring with a thin layer of Curil-T to guard against leaks (double-row shown). C: Install the spacer onto the bearing flange (double-row shown). D: Using a screwdriver to hold the center bolt in place, tighten down the 12-point nut to 24 ft-lbs maximum. I also like to add just a touch of Curil-T sealant between the spacer and the nut, just to make sure there is no oil leakage (double-row shown).

This photo shows the LN Engineering ceramic bearing installed into the case.
Figure 21

This photo shows the LN Engineering ceramic bearing installed into the case. The engineers at LN Engineering have theorized that the removal of the seal will allow fresh motor oil to lubricate the ceramic bearing, thus they have removed the seal from the rear-facing side of the bearing. The upper left inset photo shows three brand new Torx bolts from Porsche for the intermediate shaft cover. The bolts are "micro-encapsulated," which is a fancy word meaning that they simply have some sealant on the threads. I like to use new bolts to assure against leaks, but you can also reuse your old bolts if you liberally coat the threads with sealant prior to installation. The upper right inset photo shows the LN Engineering IMS retrofit kit installed. Use a small amount of Curil-T or similar flange sealant around the edge of the nut to insure against small leaks.

A: This photo shows the end of the intake and exhaust camshafts for cylinders 1ÃÆ'¢Ã¢‚¬
Figure 23

A: This photo shows the end of the intake and exhaust camshafts for cylinders 1-3 on the three-chain motor. Prior to removing the intermediate shaft bearing cover, you should have marked these camshafts. If you didn't mark them, you can set the motor to TDC and then visually inspect them to make sure that they are set to the proper timing. B: With the later-style three-chain motors, the camshafts share a long chain that wraps around the outer edge of the camshaft gear. With these motors, you must check all four camshafts to make sure they are properly timed after installing your new bearing. The 9686 camshaft locking tool is shown here in this photo, locking camshafts 1-3 on this three-chain engine. The engine must be at top dead center for the tool to fit into the pair of camshafts. If it doesn't fit, then try rotating the engine 180 degrees. With the locking tool in place, you can rest assured that your camshaft timing is set properly. I recommend that you check both sides, cylinders 1-3 and cylinders 4-6, although the 1-3 bank is the one most likely to skip a tooth. C: If you don't have the camshaft timing tool, you can use a straight edge to line it up against the edge of the camshaft and confirm that the timing is correct (as shown in the photo).

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Comments and Suggestions:
Survey Mike Comments: I have a 2002 Porsche 911 Carrera 50,000 Miles and you sparked my interest in replacing the IMS bearing . Would you also replace the clutch at the same time ? I just changed the oil and filter with Mobil 1 0w - 40w and a Porsche oil filter and saw no signs of metal particles in the filter . Can you recommend a repair shop to do the IMS bearing here on Long Island , New York ? Thanks .
October 5, 2016
  Followup from the Pelican Staff: Yes, replace the clutch at same time. Check Plandome Service center. - Nick at Pelican Parts  
Mike M Comments: I have a 2004 996 4S Porsche. I don't know what modifications were done to the "4S" engine from the regular 996 engine. Do you know if this engine is still prone to the IMS issues?
September 27, 2016
  Followup from the Pelican Staff: 2004 models have the same IMS issues. - Nick at Pelican Parts  
Ron Comments: 1999 911 CARRERA CABRIOLET
27,300 MILES
Just became aware of the issue with IMS bearing
Porsche dealer estimated $3k to $4k to replace.
Any recommendation for service in southern NH or MA. Thanks. Ron
September 20, 2016
  Followup from the Pelican Staff: Concord Motorsport in Chichester NH - Nick at Pelican Parts  
Smithe229 Comments: Hi, I desire to subscribe for this web site to obtain latest updates, therefore where can i do it please assist.
September 12, 2016
  Followup from the Pelican Staff: Bookmark this page and check back once and a while. - Nick at Pelican Parts  
JimK Comments: Porsche/Audi dealer in central IN has a 2003 911 Carrera for sale designated as "certified" with 140 point inspection with 76k miles I asked specifically whether the IMS bearing had been replaced and was told that motor met all specs. I asked but did not receive explanation of 140 pt inspection. They offered no warranty. Is dealer obligated to explain exact condition of the motor? Do I negotiate the price down to cover the cost of the bearing replacement? Suggestions please.
July 4, 2016
  Followup from the Pelican Staff: I have no idea if the dealer is obligated to do anything or disclose anything specific about the engine. Check with a local business lawyer in your area.

Negotiating is always a good idea, the IMS is a good angle. - Nick at Pelican Parts
 
Wes Comments: I am the original owner of a 2000 Porsche 996 Carrera with 33,000 miles. I only recently learned of the IMS problem and your explanation is excellent. I want to get the preventive maintenance. Can you suggest a vendor in Connecticut, Maryland and New York. All locations are equally convenient to me.
May 20, 2016
  Followup from the Pelican Staff: RPM motorsports in Long Island are good. - Nick at Pelican Parts  
Jerry Comments: Very nice well detailed explanation of the IMS bearing issue. I am a new 996 owner 2003 and am confused and concerned about the RMS and IMS. Can you recommend a shop in the Las Vegas, Nevada area that can do the LN Engineering solution?
April 17, 2016
  Followup from the Pelican Staff: I would suggest taking it to LA, Callas Rennsport. I don't know any shops in Vegas. I opened a post in our forums. A Pelican community member may be able to answer your question.
- Nick at Pelican Parts
 
ntouched Comments: Can you recommend someone in Southern California that can install one of the IMS fix kits? I have a 2002 911 Porsche Carrera tiptronic.

Thanks!

Troy
April 15, 2016
  Followup from the Pelican Staff: There is only one shop to go to. Callas Rennsport in Torrance. - Nick at Pelican Parts  
Jasem Comments: This is a very helpful and detailed inforamtion, thank you so much for posting.
March 12, 2016
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
Clint Comments: Does L&N Engineering allow DIY install of the ceramic bearing.
February 6, 2016
  Followup from the Pelican Staff: Not sure. You'll have to call them. - Nick at Pelican Parts  
Andyjenks Comments: Hi I was reading through the IMS bear procedure and all has gone to plan except I can't get the bearing out in using the LN puller and it is just stripping the threads on the bar? As far as I can tell it is a double row bearing on a 2.7 1999 car do you have any tips or advice?
December 20, 2015
  Followup from the Pelican Staff: If stuck, try lightly tapping on the puller as you screw use it to pull. Sometimes the light shock will free the bearing. - Nick at Pelican Parts  
MHiggs Comments: too-any intention of revising the article on the IMF bearing to include locking the camshafts etc -
November 30, 2015
  Followup from the Pelican Staff: Yes, we are working on updating many articles. That is one of them. - Nick at Pelican Parts  
MHiggs Comments: I have a 2001 C4 Tiptronic mine from new never any problem only 42.000 Kms done from new-no noise always changed oil every 5K klms.Now notice very slight weep of oil now at flywheel area engine to transmission joint-considering replacing the IMF bearing-read your article and all the comments too-any intention of revising the article to include locking the camshafts etc -Ill have the services of a good mechanic + myself a mechanical engineer nevertheless want to get it first time right-have you a total list of parts your recommend including flywheel seal tools etc etc so as not to have the car on the ramp for weeks M Higgins Ireland
November 27, 2015
  Followup from the Pelican Staff: I wowuld get rear main seal, IMS kit, clutch kit, fluids, etc. I’m not the best with part numbers.

Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.

To be sure, Give our parts specialists a call at 1-310-626-8765 - Nick at Pelican Parts
 
LOra Comments: I have a 2003 911, what is the typical cost to replace the IMS?
November 20, 2015
  Followup from the Pelican Staff: I don't know, it varies from shop to area you live. i would call a few Porsche work shops and get estimates. - Nick at Pelican Parts  
John Comments: Follow up for John on July 25: I contacted the installer and they told me that two of them discussed it and didn't feel it was a problem. The pieces appear to be aluminum, as only the piece on the upper right was attracted to magnetic force. Most of the other pieces left in the filter are equivalent to hair strands, not the shape or size I show in the photo those pictured are the largest I could find over the course of an hour. The filter isn't loaded with "strands" but there are several. I've never taken an oil filter apart so I really don't know what to expect. My friends, who have worked on cars for years, think I'm overreacting, but I'd rather be safe than sorry. The car seems to run perfect. Thanks for your advice, I appreciate it.
August 3, 2015
  Followup from the Pelican Staff: Thanks for the follow up and sharing your experience
- Nick at Pelican Parts
 
Fred Comments: Do I need to lock the cams using set screws if I am planning to just replace the IMS flange to stop a minor oil seap? I have a 997.1 2006 carrera s and wouldn't be able to replace the IMS bearing anyway. Thanks in advance!
July 26, 2015
  Followup from the Pelican Staff: Always lock the engine crankshaft and camshafts. - Nick at Pelican Parts  
John Comments: I recently purchased a 2000 911 and immediately changed out the IMS bearing with the LN upgrade through an L&N certified retrofitted. However, when I performed my oil change following this, I found some light debris in the filter after running about 700-800 miles after the change. The picture attached shows a few of the larger pieces, as there were a few more but they seemed to be smaller. Is this part of the break in process for the retrofit or is this a problem? I will contact my mechanic but wanted opinion from here as well. Thank you.
July 25, 2015
  Followup from the Pelican Staff: What is the material you found? Aluminum or steel?

I would contact the retro-fitter right away and let them know what you found. - Nick at Pelican Parts
 
bobster Comments: Hi, I just bought a '99 Carrera and apparently the bearing hasn't been updated. Any referrals as to who can do this for me? maybe a DIYer at home or home shop etc.
July 11, 2015
  Followup from the Pelican Staff: Where are you located?

I opened a post in our forums. A Pelican community member may be able to answer your question.
- Nick at Pelican Parts
 
R. Marshall Comments: Any feedback or information on the resulting reliability of the engine after the IMS bearing is installed?
June 14, 2015
  Followup from the Pelican Staff: In my experience, the replacement IMS bearings last quite a while and if you replace it before it fails, the engines are also reliable. Getting it out before it fails it the first step. - Nick at Pelican Parts  
Greg Comments: I have the same problem with the interior lights as Kevin. My car is a 1999 996 convertible. Please let me know if the battery cable trick worked or if anyone else has any others suggestions. Thanks.
June 13, 2015
  Followup from the Pelican Staff: Give it a shot, and let us know if it works out. I never heard back from Kevin. - Casey at Pelican Parts  
Dman Comments: 2001 Carrera vert. you talk about the exhaust cams in the paragraphs then the intake cams in the step procedure. Im confused. My IMS Retrofit kit came with cam locking tools but you never mention using them, you actually say rotate the engine after removing the tensioners??? Nobody out there in porsche land seems to do it the same. Some places say remove all 3 tensioners, you say two. You don't specify exactly which plugs to remove the access the cams - nobody explains it clearly BTW - the front of the engine rear of car or the rear of the engine flywheel end. Can you clarify? We bought your bearing kit too.
June 6, 2015
  Followup from the Pelican Staff: NEVER rotate the engine with the tensioners out. I just skimmed through the article and didn't see any mention of that. Wayne didn't use the cam tools because at the time he wrote this there were no cam tools available to the DIY'er. www.youtube.com/watch?v=hAxj6FKMzvM Here is a video I helped make with Bentley that should make the process easier to understand.
- Casey at Pelican Parts
 
Randy Comments: A clutch replacement is on the horizon for my 911 turbo 2002. Just want to know if this engine is also prone to IMS issues. I am aware that the rear main seal needs to be replace also during that time. What is a Metzger engine? Thanks, Randy.
May 15, 2015
  Followup from the Pelican Staff: Your engine does not have IMS Bearing issues. The Mezger engine is the tried and tested Porsche dry sump engine crankcase design which has been used and abused and just keeps on going.

Here is a little article which outlines some of Mezger's work. - Casey at Pelican Parts
 
kevin Comments: I have a 2001 996 and I can not get the interior lights to come on when entering or exiting the car without the key being in the ignition. I have read the manual and cannot figure out what I'm doing wrong
May 10, 2015
  Followup from the Pelican Staff: Try performing a battery reset. Disconnect both battery terminals from the battery. Using a jumper wire connect the two terminals for 15-60 minutes. This will drain the capacitors and memories from all control units. Then reconnect and try again. Is the alarm system functioning properly?? I think the alarm control unit controls the interior light functions on the 996. Does everything else seem to be operating normally? - Casey at Pelican Parts  
Lucas Comments: Lots of questions all lumped into one here so bear with me please.

Recently I picked up a 6 speed 2001 Carrera C2 Coupe. Engine number m96/0466114753

118K miles and the car drives solid.

Based on this engine ID, what IMS should I expect to find in the car? Understanding that there is a fair amount of variance in assembly.

Secondly, my mechanic, who I trust with all my german cars BMW and Benz primarily also works on porsches, but he cant get the LN or your parts through his supplier. Hes happy to have me bring in parts and he'll do the install. What special tools may he not have available to do my IMS replacement? hes done primarily IMS engine rebuilds after failure, but hes says hes never done a preventative IMS bearing replacement.

My assumption is that I need a single row LNE solution or the Pelican Parts upgrade which covers both. I also assume based on engine ID that I already have the upgraded IMS cover.

Many thanks in advance.
May 7, 2015
  Followup from the Pelican Staff:
Everything you need is right here tools and bearing kits:

http://www.pelicanparts.com/catalog/SuperCat/0905/POR_0905_ENGCAM_pg4.htm

According to your engine number you need the dual row, but you're so close to the cusp I would recommend this follow up check.
A quick check:
Have your mechanic scan the DME and if the car has DME 7.8 it needs a single row bearing. If it has DME 7.2 it SHOULD take the dual row. This information is found in the DME "Vehicle Data" Section.
If it is possible to use the IMS Solution DOIT!! I noticed that the cars run smoother and feel more solid during acceleration after installing that kit. - Casey at Pelican Parts
 
RRRUFFF Comments: Can you confirm for me if this is the flange for a double row bearing.

Thanks
April 3, 2015
  Followup from the Pelican Staff: Hard to tell because of the dirt. The dual row is usually practically flush, the single row is recessed a bit. - Nick at Pelican Parts  
Andrew Comments: I am looking for the cam locking tool / gauge to do this job on my 2004 Carrera 4S. You stated in the article that it was part 9686, but when I search for it, the tool appears to be for 997 from 2005 up. Does the 9686 tool work on the M96 engine also?
March 30, 2015
  Followup from the Pelican Staff: 9686 will work on the M96 engine. I checked Porsche repair info to be sure. - Nick at Pelican Parts  
eremite Comments: Comments: I'm considering a 2001 911 with 118K miles. Present owner says he replaced clutch when he bought the car at 110K miles, inspected IMS and didn't think replacement necessary. I note you don't advise not buying a 911 for this reason; should I wait till next clutch replacement to have bearing replaced, or do it right away?
March 23, 2015
Followup from the Pelican Staff: I would do it right away. The mileage is too high to take a chance. - Nick at Pelican Parts

Having reached that high mileage with excellent maintenance and attention to oil changes, filter couldn't it be argued that failure is less likely since it hasn't happened by now. After all, it's not inevitable.
March 25, 2015
  Followup from the Pelican Staff: My comments don't change, the mileage is high. - Nick at Pelican Parts  
eremite Comments: I'm considering a 2001 911 with 118K miles. Present owner says he replaced clutch when he bought the car at 110K miles, inspected IMS and didn't think replacement necessary. I note you don't advise not buying a 911 for this reason; should I wait till next clutch replacement to have bearing replaced, or do it right away?
March 23, 2015
  Followup from the Pelican Staff: I would do it right away. The mileage is too high to take a chance. - Nick at Pelican Parts  
sisco Comments: As an addendum to my comment below; yes you can. Made a tool to fit end of camshaft, had an assistant hold, removed sprocket gear, then rotated the cam back, reinstalled gear & set timing. Leakdown test on affected bank all less than 5%, so it appears no valve damage done. In hindsight, when tensioner for bank 1 is removed, there is not enough chain wrap left around gear, always use cam lock bar on B1.
March 19, 2015
  Followup from the Pelican Staff: I agree, the camshaft locking tools are key.

Glad you got it worked out. - Nick at Pelican Parts
 
sisco Comments: '02 996, followed above directions to the letter using set screws, shoulda stuck with cam hold down tool. Bank #1 exhaust cam jumped time-engine was rotated 360 deg & it was discovered one tooth off. Pulled scavenge pump, tried to work chain back around, jumped a few more. It was not rotated in this condition. Cams locked down on Bank 2, crank pinned out, Bank 1 intake lined up. Two questions are- did this possibly lead to valve damage? with someone holding B1 exhaust cam, can the sprocket be removed, cam rotated back, & sprocket reinstalled? Thanks for your help!
March 18, 2015
  Followup from the Pelican Staff: With chain tension relieved, you should be able to remove the sprocket and install it in the correct position. That is if the engine is properly locked down with timing tools. - Nick at Pelican Parts  
MikeT Comments: I recently bought a 2005 carrera S. I think its an M97 engine. Do i have to replace the IMS bearing?
February 18, 2015
  Followup from the Pelican Staff: 2005 does fall into the years needing an IMS retrofit. - Nick at Pelican Parts  
Larryl Comments: So what did Porsche engineers do in the 2009 that makes it a safer buy in respect to the IMS issue? Love my '70 t Targa but want to buy a daily driver and am torn between an '05-08 or stepping up to '09.
Your info is greatly appreciated.
Thanks,
LH
February 8, 2015
  Followup from the Pelican Staff: The 2009 and later Sports Cars have an engine which is completely redesigned. The "MA series" Carrera engines MA1.01 3.8 DFI , and MA1.02 3.6 DFI engines do not use the worrisome intermediate shaft design with roller bearing at the rear. There are other nice things they did to the engine including use of real gaskets for valve cover and oil sump instead of the cheapo liquid gasket utilized on the M96 and M97 engines.

Here is an article written by our friends Tony Callas and Tom Prine on the subject of the difference between M96 and MA series engines.

http://www.callasrennsport.com /996-vs-997-and-beyond/
- Casey at Pelican Parts
 
Larry Comments: This is a very detailed and informative article on the 996/997.1 IMS problem.
Thank you,
Larry Hutt
February 8, 2015
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
devin Comments: The debris found in the oil pump pickup looked very similar to the example picture you have in this article. Mostly metal flakes with some plastic pieces. The engine seems to run quite smooth without miss fires it just has a tap/ticking noise from the rear of the motor. Thank you for your input and expertise.
January 27, 2015
  Followup from the Pelican Staff: Depending on the color, plastic is usually chain rails or water pump. The metal could be IMS bearing, if it is steel. - Nick at Pelican Parts  
devin Comments: I have a 99 boxster with the 2.5l. It has a tapping noise at any rpm. It was diagnosed to be coming from the Left cylinder head and a collapsed exhaust lifter was found and all bank 2 lifters were replaced. It still has a ticking or tapping noise and the noise seems loudest from the bottom rear of the engine. Do you think this is likely a bad ims bearing? The sump was removed and some debris was found and cleaned out.
January 27, 2015
  Followup from the Pelican Staff: What type of debris was found?


Is steel debris, likely the IMS. - Nick at Pelican Parts
 
Tommy Comments: 56 reg Cayman S 3.4. Having the IMS bearing replaced as soon as I pick up the car. Being the MY06 engine, is it more of an expensive job being this year 2006 opposed to the 2005. I have been quoted 1800 including VAT. Does this sound correct?
January 8, 2015
  Followup from the Pelican Staff: Price shouldn't change too much. I am not sure of what it should cost. Call a few different shops to compare the estimate. - Nick at Pelican Parts  
lennyg Comments: We are considering the purchase of a 2007 Carrera Targa 4S with tiptronic. Is this car a potential candidate for IMS replacement or will it get away with the later mfg year?
January 3, 2015
  Followup from the Pelican Staff: I believe so. - Nick at Pelican Parts  
Jim Comments: I have a 2004 911 Carrera 4 S with 44,000 and don't know if the IMS bearings has been replaced or not as I am the 2nd owner. Do you recommend it be replaced regardless if it was previously or not? Would a review of previous services be noted running the VIN by a porsche shop?
January 2, 2015
  Followup from the Pelican Staff: If it was done at a dealer it would be on record. If not, then you would have to know where the vehicle was serviced. I would say it is always best to repair common issues. Especially if you are unsure of the history. - Nick at Pelican Parts  
rickz Comments: I have a 2008 C4S. Does this model have the same IMS problems?
January 1, 2015
  Followup from the Pelican Staff: I believe 2008 was the last year with the engine. I think it is an M96. You do have the IMS that causes issues. - Nick at Pelican Parts  
Ten57 Comments: On a 2006 Cayman S do you need to completely remove the chain tensioners 2-3? or just loosen them?
December 18, 2014
  Followup from the Pelican Staff: Set the engine to TDC, lock the camshafts and crankshaft, then remove the tensioners. - Nick at Pelican Parts  
pwhitty Comments: I have a 2005 997 with 105,000 miles. It has the 3.6L engine. Does the ims bearing issue occur with this motor?
What motor would this one be M96 or M97? or are these the 3.4L engines?
November 19, 2014
  Followup from the Pelican Staff: I think it is an M96. You do have the IMS that causes issues. - Nick at Pelican Parts  
Broski Comments: I'm about to purchase 2001 911 C2 with 18k on the speedo. It's been well cared for and never driven in the winter hence the low miles. Since it 's been babied but serviced on a regular basis should I be worried about driving the car from Ohio to Oregon? With regard to the IMS bearing? It a 2500 mile journey and I can't afford a failure.
October 30, 2014
  Followup from the Pelican Staff: You can have the oil tested to see if there is steel in it. If there is, replace the IMS right away. - Nick at Pelican Parts  
kootsi Comments: Sometimes the problem does not originate with the IMS, but the symptoms make it seem like it has. The tandem oil pump can fail, allowing oil into the vacuum side of the pump. The pump tries to compress the oil, which it can't and the end gear will shear. This metal can get into the oil, cause the other secondary pump to fail as well. Metal,can then get into the gear of the intermediate sham causing the chain to slip timing, resulting in engine cam DTC codes at best...engine failure at worse.
October 15, 2014
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
waz Comments: I am considering getting 2007 Boxster S with 3.4 lt engine - does this engine suffer this issue - if so .. is there a bulletproof version available from LN engineering?
October 4, 2014
  Followup from the Pelican Staff: 2007 has a newer bearing design and is supposed to be better. With that said, LN does have good replacement parts for the bearing, if you decide to retrofit it. - Nick at Pelican Parts  
AC Comments: Would you recommend removing the grease seal on the conventional retrofit bearing in your kit prior to installation? The folks at LN Engineering suggest this would prolong the life of the bearing http://imsretrofit.com/lubrication/. Thanks.
September 11, 2014
  Followup from the Pelican Staff: I'm not a fan of this. I think that debris can possibly get into the bearing and cause it to fail. I've seen engines where this indeed may have happened. Since I recommend replacing the bearing every 30,000 miles or so regardless, I don't think removing the seal is necessary, and the potential downside risks are greater than the benefits. That said, Charles at LN Engineering advocates the removal of the seal to encourage more lubrication of the bearing itself. The bottomline is that frequent oil changes are your best friend in prolonging bearing - removing the seal may assist or not - it's really difficult to say one way or another. - Wayne at Pelican Parts  
Will Comments: As a follow up question, if the guard let me know the ims bearing was failing, what could I do about it in the later model 997.1 if the bearing isn't replaceable? Thanks.
September 11, 2014
  Followup from the Pelican Staff: The bearing can be replaced. You have to disassemble the engine. I have heard of some modifications that can help prevent failure. Try the folks at IMS Solutions. - Nick at Pelican Parts  
Will Comments: I was thinking of purchasing a 2006-2008 997, which looks like doesn't have a replaceable bearing. If that's the case, would it even make sense to install something like the IMS Guardian? I wouldn't be able to afford a new engine if this were to fail, but am fine with regular maintenance and such.
September 8, 2014
  Followup from the Pelican Staff: Well, if you installed it, you just know when it would fail. Enabling you to catch it in advance. - Nick at Pelican Parts  
Perry Comments: I am having shop install LIN kit in my 2003 911 C2, it has 88k. Only had car 2 months, seems great so far. How long til I replace again? With regular oil changes , what kind of realistic service can I expect from car as daily driver? Thanks
August 19, 2014
  Followup from the Pelican Staff: This is a big topic of debate. I have heard around every 60k. Some say longer. Check with LN to see what they say about their bearing. - Nick at Pelican Parts  
bruce Comments: I goofed up and need some advise. I installed the older style ims bearing upgrade correctly but the holding Allen screws were to loose and the ims shaft shifted up so I can not re install the ims cover plate. Is there any other option than to remove the engine.
August 18, 2014
  Followup from the Pelican Staff: Take the end plate off and take some screwdrivers covered with duct tape (to soften the ends), and then guide the intermediate shaft into place. You may have to remove the tensioners completely in order to do this, including the one in the front by the AC bracket. Once you release almost all of the tension on the shaft, you should be able to move it into place. You will have to recheck the timing to make sure that the chain didn't skip a tooth or two. - Wayne at Pelican Parts  
FL911 Comments: DOF Direct Oil Feed kit
Sorry
August 14, 2014
  Followup from the Pelican Staff: No problem. Looks like Wayne has your question covered.- Nick at Pelican Parts  
FL911 Comments: I have a 2002 Carrera. From what I have read it will have the 5 chain timing chain setup correct?
Next question: If I decide to go with the Direct Oil Feed option from Tune RS Motorsports, will the installation tools that Pelican sells still work?
Why does Pelican not sell the DOR kit????
August 14, 2014
  Followup from the Pelican Staff: Your car should have the early, five-chain setup unless the engine has been replaced at one time. You never quite know until you take a closer look. As for the DOF kit, we have not had the opportunity to adequately test and evaluate this kit for proper operation and longevity. As of this writing, it's relatively new and there aren't a lot of installations out there. I'm also not sure if the tools that we sell will fit this kit - I suspect you'd have to ask them or check out the installation instructions. - Wayne at Pelican Parts  
Russ Comments: My 2002 carrera 4 engine was replaced in 05/2006 with engine #M96/03AT66566034. Based on the engine serial number what IMS was installed???

Thanks RJC
June 22, 2014
  Followup from the Pelican Staff: I think your vehicle will have a single row IMS. Give our parts specialists a call at 1-888-280-7799. They may be able to answer the question for sure.- Nick at Pelican Parts  
Rkakar15 Comments: How much would this cost from a non dealer porsche mechanic?
June 19, 2014
  Followup from the Pelican Staff: Not sure, you'll have to call around and get some quotes. - Nick at Pelican Parts  
Rkakar15 Comments: How do you know if it's already been done to a car your buying from wholesaler?
June 19, 2014
  Followup from the Pelican Staff: The only way to know for sure is if there were service records. - Nick at Pelican Parts  
Dave Comments: The article notes that the IMS bearing is suppose to stay dry. I'm a little confused on how proper and frequent oil changes would reduce the risk of failure.
June 10, 2014
  Followup from the Pelican Staff: I believe the issue is stagnant oil sitting in the IMS tube, causing the seal on the bearing to dry out, then oil washes the grease out of the bearing. Keeping up with oil changes will keep the engine cleaner overall. - Nick at Pelican Parts  
scottjk Comments: Just finishing LN Engineering IMS install purchased from Pelican. According to LN the center bolt torque specification is 7.5 ft/lb not 24 ft/lb as listed in your guide.
May 21, 2014
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
KrustyEggroll Comments: My 2002 996 C4S just had a new intermediate shaft complete shaft from Porsche replaced during an engine rebuild; the new shaft is supposed to be ok and not like the original shaft I'm told, is that correct? i.e. they did not install the LN Engineering IMS bearing kit...
May 6, 2014
  Followup from the Pelican Staff: If Porsche repaired it, they used factory parts. They will be high quality parts. - Nick at Pelican Parts  
TMan Comments: I'm considering purchase of 2002 911 Targa with low mileage 20,300. Obviously low mileage would indicate it hasn't been driven alot. I'm concerned about IMS bearing failure. Should I go ahead and change the IMS just to be safe? Are the diagnositic tests to determine if there are any problems which you mention a good indicator that the IMS could wait until the first clutch job at 30-40 thousand miles? Thanks Tom
April 26, 2014
  Followup from the Pelican Staff: You can check for oil leaks at the bell housing or have the oil tested to see what metals are present. Other than that, replacing it as routine maintenance is best.- Nick at Pelican Parts  
CB Comments: I'm considering buying a 2006 911 with 40,000 miles. Does that year and those built afterward have a problem with the IMS bearing? Is this a model year to avoid? Are there some model years that don't have the IMS problem?
April 22, 2014
  Followup from the Pelican Staff: They do have the issue. But with proper maintenance and service, it should be easy to deal with. This issue wouldn't prevent me from buying one. - Nick at Pelican Parts  
Bob Comments: I just installed an L/N IMS bearing. I used their installation kit and locked everything down as instructed.
However, when I started the car it is not idling very well at 800 rpm. I scanned the car and got a P-1531 error code. The description reads Camshaft Adjustment....Bank 1...short to short. When installing the motor I noticed the passenger side Vero Cam sending pluges two wires were cut.
I re-spliced them and am wondering if I did not get them spliced correctly?? Anyone have any ideas?
February 10, 2014
  Followup from the Pelican Staff: This code can be set by a bad actuator, solenoid or timing issue. I would double check your timing first. - Nick at Pelican Parts  
Joseph Comments: Dear Pelican Staff,

I am interested in purchasing a use 2002 911 Porsche but this problem with the IMS is very disturbing for it to completely wipe out the engine. If a newer model like the 2006 still has the same problem, what year did Porsche rectify this problem? I would like to buy a used 911 Porsche but if this is a continuous problem then the 911 may not be a car to invest in. Can anyone at the Pelican Staff inform me about a better year for the 911 Porsche?

Thank you
February 2, 2014
  Followup from the Pelican Staff: The IMS really isn't a reason not to buy a 911 or a certain year. Just keep up with repairs and replace the IMS before it become s a problem. - Nick at Pelican Parts  
Jim Comments: Does the IMS bearing issue occur in the 2006 3.8 liter engine?
September 1, 2013
  Followup from the Pelican Staff: On 2006 models, the IMS bearing is captured int he crankcase. Some mechanics note that this bearing is problematic also, however complet engine disassembly is required for replacement. Maybe best left to the Porsche pros. - Nick at Pelican Parts  

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