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Upgrading to 911 Turbo Valve Covers (and stopping those leaks!)

Pelican Technical Article:

Upgrading to 911 Turbo Valve Covers (and stopping those leaks!)


1-2 hours






Torque wrench, degreaser, rags, metric socket and metric wrench set

Applicable Models:

Porsche 911 (1965-89)
Porsche 912 (1965-69)

Parts Required:

911 Turbo valve covers, valve cover gaskets kit

Performance Gain:

Eliminate the oil leak from your magnesium valve covers

Complementary Modification:

Replace the oil and filter
     One of the most common problems with the older 911s is the occurrence of major oil leaks.  While some oil leaks are harder to fix than others, the oil leaks that originate from the 911 valve covers are very easy to fix.   From 1968-77 the upper valve covers were magnesium.  While very lightweight, there is a coefficient of thermal expansion mismatch between the cam tower and the valve covers.  In other words, when the engine heats up, the valve covers expand at a different rate than the cam towers.  This causes the magnesium covers to warp, and subsequently leak.  It is this leak from the valve covers that is very common on the older cars.  If your SC or Carrera is leaking from the bottom covers, the Turbo valve covers that are reinforced, will help prevent this leak.   Since this is a very common upgrade, it may have already been performed on your car.  Check to see if your covers have been upgraded before you order a new set.   The newer ones are all aluminum, and the lower covers have fins that criss-cross the outer surface.

     To see if your car is suffering from valve cover leaks, take a look under the car and check the bottom of both the left and right valve covers.  If there are oil drips there, as well as oil on your heat exchangers, there is a good chance that your covers are leaking.   Check the ones on top too, from within the engine compartment.  These are also very prone to leaking.  A good way to check for leaks is to clean the entire engine.   You can clean the bottom of the engine by taking it to a self-serve car wash that has a degreaser setting on the nozzle.  Don't spray any water inside the engine compartment, as there are many things in there that you just don't want to get wet.   Instead, use some degreaser on a rag to wipe out the inside of your engine compartment.  Please don't dump any degreaser on your driveway, as this pollutes the environment.

     If you suspect that your valve covers are leaking, then simply remove them off of the engine and check to see if they are warped.  Figure 1and Figure 2show both the front and backside of the standard, early magnesium valve covers.   If you place these on a flat surface, you can check to see if they are warped or not.  Even if they don't appear to be warped, remember that they will deform when they are heated by the motor.  If the valve covers are warped, then you should definitely replace them.

     The standard upgrade is to replace the valve covers with late 911 Turbo valve covers.  This is a bolt-on replacement for 911 owners.  Make sure that you empty the motor of oil before you remove the valve covers, as there is a good chance that you will have a major oil spill if you don't.  The Turbo valve covers are made of aluminum, and will expand at the same rate as the cam towers, decreasing the amount of warpage.  The upper valve cover, shown installed in Figure 3, looks very similar to the original magnesium one, except for the fact that it is unpainted.  The lower valve cover, shown both in Figure 4and Figure 5has fins to improve cooling and also increase stiffness.

     If you own a 914-6 or are performing a 914-6 conversion, you need to machine down a section of the valve covers in order to have them clear the rear trailing arms.  If you don't do this, then you will not be able to remove the covers without either removing the studs from the cam towers, or dropping the engine.   Figure 6and Figure 7show the area of the lower covers that must be machined off in order to make the valve covers fit.  This needs to be done to both sides.  The fins must be machined down about a quarter of an inch in order to accommodate the rear trailing arms of the 914.  Machining the covers will not hurt them, and they will still function very well.

     When you install the Turbo valve covers, make sure that you use a new set of valve cover gaskets, screws and washers.  Figure 8shows the valve cover gaskets, and Figure 9shows the complete kit with all the nuts, washers and gaskets.  It is important not to overtorque the nuts on the valve covers.   I was not able to locate a torque specification in the factory manuals, but I would not torque them greater than 8 ft-lbs.  Make sure that you torque them down in a diagonal pattern, and it is advised to start at 4 ft-lbs, and then after all of them are tight, re-torque to 8 ft-lbs.

     Well, that's about it.  It's a really easy upgrade that should stop one of the most annoying leaks on 911s.  No more smoke coming out of the rear of the car as the heat exchangers burn off excess oil!  Pelican Parts carries the 911 Turbo valve covers, and the valve gasket kits at competitive prices, as seen in our 911 on-line catalog.   Please remember that your continued support and purchases directly impact the development and expansion of this site.  Please help to keep the site growing by letting us earn your business.

Figure 1

Magnesium Valve Covers

Figure 2

Magnesium Valve Covers (underside)

Figure 3

Upper Turbo Aluminum Valve Covers

Figure 4

Lower Turbo Valve Cover

Figure 5

Lower Turbo Valve Cover

Figure 6

Machined Edge of Lower Turbo Valve Cover

Figure 7

Machined Lower Turbo Valve Cover

Figure 8

Valve Cover Gaskets

Figure 9

Valve Cover Gasket Kit

Comments and Suggestions:
Volney Comments: I want to upgrade my 1979 SC to Turbo lower valve covers. I understand the correct part number is 930.105.116.00. But, I also see different part numbers for the Turbo valve cover, e.g. 930.105.116.0R or 930.105.116.02? What is/are the correct numbers I can use for the SC? Thank you! Volney
September 23, 2013
  Followup from the Pelican Staff: Give our parts specialists a call at 1-888-280-7799. They can help you find the right parts. Or try this link: #item22- Nick at Pelican Parts  
Willie Comments: I'm in the middle of a reseal job on my 1990 911 C4. I've just got the heads back from the machine shop and was told that there is a technical bulletin out regarding replacement of the cylinder head studs. Do I need to do this? The original ones appear to be in excellent shape. There was, however, some evidence of leaks at the head/cylinder mating surface. Also, I was told that there was a fix to the head leak problem involving machining a groove into the head at the cylinder mating surface and then placing a seal in the groove. The machine shop did not, however, machine this groove into the head. What is proper fix on this situation? The oil leak problem seems to have come primarily from cylinder base to case seal.
January 3, 2012
  Followup from the Pelican Staff: If there is a bulletin on the studs, I would replace them if it applies to your vehicle. I have not heard of the groove being cut, I was under the impression only early engines had this groove.- Nick at Pelican Parts  
BOB Comments: Thanks for the info on the valve. I have a leak only air but may change soon. What is the pattern and toque for tigthen the covers . Tahanks again BOB
June 17, 2011
  Followup from the Pelican Staff: Could you specify the year and model of the car? - Nick at Pelican Parts  
Gary Comments: I have an 85' carrera 3.2L that idles rough. But about every 20 seconds the idle drops off like the engines going to die and then comes back. Is this the idle control valve? Fuel pump?
December 28, 2010
  Followup from the Pelican Staff: These 1984-89 Carreras are really difficult to diagnose because they don't output any trouble codes that can direct you to what component is failing. The most common problem is with vacuum leaks - be sure to check the whole system to make sure that your car has none. Then, start looking at the idle control valve - it may be dirty. Also, the hunting problem may be related to a mixture issue - you should have the mixture of the car tested and perhaps adjusted - that may help as well. - Wayne at Pelican Parts  

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Page last updated: Fri 2/23/2018 02:23:39 AM