3.6 Engines

The 3.6 litre engines really have excellent power improvement potential with a few caveats which are discussed below.

RS Mid-weight Flywheel & Clutch kits

We are offering a mid-weight version of the RS lightweight flywheel & clutch kit for people who want better throttle response and engine acceleration. The regular RS flywheel weighs 12 lbs (against the OEM Dual-Mass 38 lb one), but can lead to engine stalling problems with the 964 and ’95 993’s. Later 993’s, ’96-’98, aren’t as prone to stall with the RS flywheel provided everything on the engine is in good condition and functioning correctly.

Our mid-weight RS flywheel adds 7 lbs which adds sufficient inertia to keep it from stalling when the RPM’s drop too quickly for the Motronic system to catch it.

We providing this as a complete kit containing everything needed to do a proper clutch replacement.

These kits include:

RS mid-weight flywheel, RS ring gear, RS pressure plate, RS clutch disc, RS guide tube, pilot bearing, release bearing, pressure plate bolts, flywheel bolts, rear main seal, and slave cylinder (which they always need) for $ 2751/complete.  The regular RS flywheel & clutch kit runs $2300, same as above.

Pictures coming soon.

 

Known Issues

Distributor belt breakage

The 3.6 was the first production 911 engine that came equipped with twin-ignition. Porsche used a unique dual-distributor that was inexpensive to produce, compared to the RSR unit, that was generally reliable. The only problem was a premature failure of the rubber belt that drives the second unit caused by ozone gas buildup inside the distributor. When the belt broke, the second rotor quit turning, resulting in erroneous timing in the cylinder that the rotor was pointing at the time of breakage. This usually resulted in serious damage to that piston and cylinder. Installing the factory vent kit fixed this problem by forcing pressurized air from the cooling shroud through the distributors to evacuate the ozone gas that attacked the rubber. We do offer a distributor rebuilding service to replace the belt and bearings, if needed.

These engines were also equipped with a knock sensor on each bank of cylinders so that the Motronic unit could selectively retard a cylinder that was detonating.

Although Porsche claims a compression ratio of 11.1:1, we have measured many of these engines and they range from 10.6 to 10.8:1. The only pistons that truly had the 11.3:1 compression ratio were the 102mm pistons from the 3.8 RSR engines.

Cylinder Leakage

The first generation of 3.6 litre engines from 1990 to early 1992 didn’t use a head gasket which caused some leakage to be observed from between the heads and the top of the cylinders. In most cases, this was simply a small seepage of oil which looked far worse than it really was. Porsche solved the problem by installing sealing rings in early 1992 to prevent serious leaks and the rest of the 964 and 993 engines all had gaskets.

For owners of these early 964’s without gaskets who have some leaking issues, we can fix this problem by machining the heads for sealing rings and modifying the top of these early cylinders to fit and seal better.