Additionally, I am excited to announce a whole new series of technical articles based on the 911. We are starting two project cars, a 1982 911SC, and a 1973 1/2 911 Targa. Both are similar, yet from different 911 vintages (early targa / later coupe) that they make excellent subjects for our series. This series will correspond with a new book that I am writing for MotorBooks International! We'll leave it at that for now, except to say that there will be a tremendous amount of tech articles appearing on the site for the 911 very soon.
That aside, our first article in the series is this 911 engine removal (engine drop) article. Unfortunately, performing engine work on the 911 requires that you remove it from the car. The tight spaces within the engine compartment don't lend themselves to easily repairing oil leaks or other significant problems on the car. Basically, there are a few things that you can do with the engine in the car (valve adjust, fuel injection work, carrera chain tensioner update), but most operations require that you pull the engine.
In this article, we used a 911SC as the model. The procedures for most other cars are going to be similar except for a few modifications. I will try to be as clear as possible in describing the potential pitfalls with other models of 911s. If I do leave anything out, don't hesitate to email me with some more suggestions. Our tech articles improve with age as people continuously write in and give additional hints and tips learned from their own experience.
For your reference, I have summarized the steps required to remove the engine into a handy table. I would suggest that you print this out and check off each item when you complete it. It is very easy to damage a hose, wire or linkage if left connected to the engine when you are trying to drop it down. Here's Master Checklist for Lowering your 911 Engine (911SC):
- Disconnect Battery
- Remove Fuel Pump Relay
- Empty Oil from Engine Sump
- Empty Oil from Oil Tank
- Raise Car on Jack Stands
- Disconnect Hard Oil Line
- Disconnect & Remove Rubber Oil Line
- Disconnect Clutch Cable, Arm, and Helper Spring Assembly
- Disconnect Starter Solenoid Electrical Connections
- Disconnect Reverse Backup Switch from Transmission
- Disconnect Heater Hoses From Heat Exchangers
- Disconnect and Remove Shift Coupler
- Disconnect A/C Compressor and Tie to Side of Car
- Disconnect all Fuel Lines
- Disconnect Main Engine Wire Harness
- Disconnect Breather Hoses
- Disconnect Accelerator Linkage Bar
- Disconnect Cruise Control Cable
- Disconnect Oxygen Sensor
- Remove Four Nuts that Hold Engine to Tranny
- Remove Engine Motor Mount Bolts
- Lower Engine Down
- Pull Engine Away from Transmission
- Lower Down onto Cart and Remove
The first step in removing your engine from the car is to disconnect the battery. You do this for quite a number of reasons. Firstly, the cable that connects to the starter is always live, and you will have to disconnect it to remove the engine. Secondly, you don't want to accidentally turn on the ignition and the fuel pump when there is nothing attached to the lines. Disconnecting the battery is important; don't forget it. Additionally, you might want to remove the fuel pump relay in the front trunk as an added precaution. Sometime later on, when the engine is still out of the car, you may have an opportunity to test some part of the car that needs electricity, and you may forget that the fuel pump might go on.
Once the battery is disconnected, it's time to empty the oil out of both the engine and the oil tank. The 911 motor is designed around what is called a dry sump oil delivery system. This name is somewhat deceiving, however, because there is a rather large oil reservoir at the bottom of the engine case. If at all possible, make sure that the engine is warmed up when you remove your oil. The hotter the oil, the more smoothly it will flow out of the engine. This results in more particles and debris being removed from the engine.
The first step in changing your oil is to remove the oil filter. You want to do this first, because there is often oil left in the filter, and when you remove it by twisting it, this oil has a tendency to flow back into the tank. 911 oil filters can be notoriously difficult to remove. The oil filter is located in the engine compartment on the passenger side. Filter removal wrenches are sometimes a good idea, but I haven't been ever able to find a wrench that I was able to easily fit around the filter in any of my cars. I recommend first trying to remove it using your hands. Ask your 240 lbs, weight-lifting, 23 year old neighbor to help if you happen to have one of those handy. You remove the filter by turning it counter-clockwise. Make sure that you place paper towels under the filter, as it will leak some oil onto the wire harnesses that are located directly below, as shown in (Figure 1). If you cannot get the oil filter off, then you need to use other means.
For pesky oil filters, I usually drive a long screwdriver through the filter and out the other side. This then gives me a long torque-arm to remove the filter. The disadvantages to this method is that you can no longer drive the car once you poke a hole in the filter, and you can create a large mess as oil leaks from this hole. You can also tear the oil filter, and be stuck with a worse situation than before. This, fortunately, has not happened to me yet.
Once you get the oil filter off, make sure that you clean up the oil that spilled. If you don't , Murphy's law says that you will drop a tool into it, or accidentally stick your hair in it when you are trying to remove something else on the engine.
The next step is to empty the oil tank. The oil tank is located on the passenger side of the car (the oil filter actually screws directly into a console that is attached to the tank, as shown in (Figure 2). The tank is located just inside the fender of the car. The drain plug for emptying the tank is located on the bottom of the tank, and can be see if you look under the rear bumper. (Figure 3) clearly shows the drain plug that you need to remove in order to empty the tank. Use a socket wrench to remove this plug, and just as it is ready to come out of the tank, be sure to be careful, as hot oil will come out at a rapid pace. Make sure that you have a large pan underneath the oil tank. The maximum size that you would need is about nine quarts, but the oil that comes out of the tank is usually never that much. Make sure that you have plenty of paper towels too, and that your drain pan is large. This is because no matter how many times you do this, the oil stream will flow in a different direction, usually away from your drip pan, as shown in (Figure 4).
After the oil tank is empty, re-install the drain plug into the oil tank. Chances are that the plug fell into the oil drip pan when you were removing it, so careful dish it out when the oil cools down. Make sure that you use a paper towel to clean off the plug well, as shown in (Figure 5). These plugs are often magnetic, and trap bits of metal that wear off of the engine. Clean it very well using a paper, not cloth, towel. Any stray paper fibers will dissolve in the engine oil later on; the cloth fibers have a tendency to clog tiny oil passages. Tighten the drain plug - don't leave it loose - as you could forget to tighten it when you are adding oil later on. The anxiety to start up an engine that has been out of the car is so great, that you will have to resist the temptation to rush things. But more on this in another article.
The emptying of the engine sump is similar to the draining of the tank. (Figure 6) shows the underside of the engine with the oil sump plate visible. Remove the drain plug on the bottom of the sump plate in the same manner that you removed the oil tank drain plug. Be careful once again of the hot engine oil. Once the oil is all drained, clean the plug and reinstall it. Don't tighten either of the drain plugs too tightly, as they don't need to be cranked down.
Now, you are ready to jack up the car. I don't usually like to jack up the car before emptying the oil because once the car is up in the air, the engine is at a severe angle, and all of the oil may not drain out. You jack up the car by placing your jack under the engine sump plate. Get a real jack for this task, as the jack that came with the car will not do, and you will also need one later on for removing the engine out of the car.
Make sure that you place a block of wood, or an old rolled up newspaper under the sump plate to avoid damaging it with the jack, as shown in (Figure 7). The newspaper acts as a nice firm cushion, and protects the bottom of the engine, as shown in (Figure 8). I recommend jacking up the car as far as it can go with your jack on the engine, as shown in (Figure 9). Unless you have a really huge jack, you will probably have to place a block of wood under the engine or jack and jack it up even more to achieve the desired ground clearance. You should place your two jack stands under the torsion bar covers, as shown in (Figure 10). The first time that I heard of using these covers to support the car, it didn't seem like an intelligent idea to me, but after talking to many, many people, it seems like these covers are more than strong enough to support the weight of the car.
I feel it necessary to say a little about jack stand safety. Every year, there are a few people who are killed by their cars falling on them. I do not wish to see you be one of them. A rule of thumb that I practice whenever I jack up the car is to check the entire support of the car after you are finished jacking it up. I always try to knock the car off the jack stands by pushing it, shoving it, jumping on it, etc. You should not be able to move the car even a sliver of an inch. If you can, it's not correctly supported. It is better to have the car fall off the jack stands when you are testing it, instead of when you are underneath it. I always use a backup set of jack stands placed underneath the floorpan too. All of these seem to be manufactured in China and other parts of Asia nowadays. Without knocking Asian products, occasionally there are quality problems. I would hate to see a large bubble in the casting of the metal used in my jack stand be the reason I became crushed by my car. My point - use a backup pair of stands just in case. These are also good if you live in earthquake zones like I do.
In order to have the engine's fuel injection system clear the rear of the car, you need to raise the car pretty far off of the ground. I found with the CIS system, you needed to elevate the car 24.5" at the torsion tube covers, which resulted in a total of 32" clearance from the bottom of the rear spoiler to the ground. Of course, these numbers vary depending upon what type of fuel injection you have on your car, and also the ground clearance of the cart or jack you are using. You can always increase the HEIGHT of the car later on, but this is a bit more difficult, because you probably won't be able to jack up the car using the engine, and you may be using your only jack to support the engine. (Figure 7) can give you an indication of how high you need to jack up the car prior to removing the engine.
Once the car is elevated to a good HEIGHT, you can begin working underneath to disconnect everything that you need removed in order to pull the engine. Start by disconnecting the hard metal oil line on the passenger side of the car. There should be a junction towards the right rear of the car, as shown in (Figure 11). The other line connected to this junction is connected to the bottom of the oil tank. Use two adjustable crescent wrenches to loosen this nut up. On my relatively rust-free 1982 911SC, this took a tremendous amount of force to remove, so be prepared. You may need any extra long wrench and/or breaker bar. Be careful not to bend or damage the hard line that runs underneath the engine.
Now, remove the soft rubber line that goes between the oil tank and the oil cooler. This line is usually connected with hose clamps on each end. Make sure that you have a drip pan handy, as there usually is some left over oil in this line that will drip down onto the floor. Carefully inspect the oil line when you remove it, and if it looks old, cracked or worn, then count on replacing it. Make sure that you stuff the oil cooler hole (Figure 12) and the oil tank hole (Figure 13) with a paper towel to soak up any additional left over oil that might seep out.
Now, move to the clutch cable lever arm assembly under the car, as shown in (Figure 14). Start by loosening up the nut that holds and adjusts the clutch cable, as shown in (Figure 15). You should be able to disconnect the clutch cable end and remove the clutch cable out of the way, as shown in (Figure 16). Now, remove the small return spring that helps remove the backlash from the linkage, as shown in (Figure 17). Make sure that you disconnect and remove the spring , because it will most likely get lost. Now, remove the small circlip on the small lever arm, as shown in (Figure 18). Slide this arm off its shaft using a small screwdriver. This is shown in (Figure 19). Once this arm is off, the main arm assembly should be able to be slid off. Beware of the 'U-shaped' clutch arm helper spring, as this is loaded pretty tight, and will spring back when you pull off the arm. The helper spring can only move within a small radius, so you don't have too much chance of getting hurt unless you purposely stick your fingers in there. (Figure 20) shows the entire lever arm assembly being removed. After the entire assembly is removed, the bottom of your transmission should look like (Figure 21).
Now, move to the starter and disconnect the wires that lead back to the engine. There should be a few of them that lead towards the rear of the car, and one or more big ones that go to the front of the car, and to the battery. At this time, it would be a bad idea to have your battery connected, so if you didn't disconnect it previously, go do it now. (Figure 22) and (Figure 23) show the wires that you need to disconnect from the starter. Make sure that you tuck them out of the way.
Move to the rear of the transmission, and you will find a plug for the reverse light switch. Remove the wires that are plugged into the transmission and push them off to the side. (Figure 24) is a bad picture of the area where the plug is located. You might have some trouble getting your fingers in there to remove the wires. Be aware that if you use some pliers to pull on the wires, then you might have to resolder the ends back onto the wires if they pull off.
Now it's time to disconnect the heater hoses from the heat exchangers. No need to remove the exhaust here, as it will come down with the rest of the engine. (Figure 25) shows the heater hose connected, and Figure 26shows it disconnected. Just push them out of the way for now.
An often overlooked step is the disconnection of the shift linkage in the center tunnel. If you don't disconnect the transmission from the link prior to lowering the engine, then you can bend and damage the shift lever in the transmission. You can guess how expensive that is to fix! Start by moving to the inside of the car, and removing the access panel that is located in the center of the car, just behind the two front seats. This panel is shown in (Figure 27). Remove the four screws that hold the panel on, and you should see the shift linkage coupler covered by a rubber boot, as shown in (Figure 28). Pushing the boot aside reveals the shift coupler, shown in (Figure 29) and (Figure 30). Use an 8mm hex key or socket wrench to remove the small cone screw that holds the coupler to the transmission selector shaft. Then, slide the coupler off as shown in (Figure 31). Once the coupler is removed, then your car should resemble (Figure 32).
Now, you are ready to tackle the inside of the engine compartment. Start by removing the A/C compressor from the engine. When you remove the engine, you don't want to have to disconnect the entire A/C system, so the recommended procedure is to push the compressor off to the side of the car. Start disconnecting the compressor by removing the bolts that hold it to the compressor bracket. (Figure 33) shows the mounting bolt in the lower rear corner. (Figure 34) shows the mounting bolt that is located behind the compressor, hidden from view. (Figure 35) shows another mounting bolt and the belt adjustment screw. You need to remove all of these bolts and loosen up the belt tension adjustment bolt. Once the compressor is free, and the belt is loose, you can slide it off of the compressor clutch, as shown in (Figure 36). Make sure that you disconnect the electrical connection to the compressor as shown in (Figure 37). Make sure that you grab a thick terry cloth towel and drape it over the side of the car as shown in (Figure 38). Place the compressor against the towel, and tie it up firmly with a bungee cord or tie down, as shown in (Figure 39). When the compressor is removed, the engine mounting bracket should resemble (Figure 40).