3.6 993 engine installed into factory SIX, thoughts and guidance Options

[jim dorociak]

Guys I am collecting parts for my restoration. My car came without a drivetrain so I am looking at a collection of parts and what makes the most sense. I have 90% of a 95 993 engine that I have been collecting - one side of me says high compression dual plug, hydraulic lifters, torque and turn the key it starts right up without any drama. Or a short stroke - and you know where this goes - dual plug, special distributor, P/C's (not cheap) Carbs probably new PMO 46 (also quite a bill) and then the exhaust system with heat.

Does the factory front motor mount work on a 993 engine? I know the tin has to be married from 914-6 and 993 engine tin.

jdorociak@gmail.com

Jim

[ClayPerrine]

Some things I have found, and I have been there, done that.

1. The factory motor mount in a 914-6 is fine for a small engine. Not so good for a 3.6. The engine will move too much with that style mount. Even the 3.2 Motronic engine I put in a factory six years ago was questionable and would eat motor mounts.

2. The factory front mount for a 914-6 wont' fit a 3.6 engine. It is not deep enough for the pulleys on a 3.6

3. The engine tin requires extensive modification to make it work with a 3.6. The timing covers on a 3.6 taper, and the front tin won't fit. There is no oil cooler, so something has to be fabricated to go in it's place, and you HAVE to have an external oil cooler setup. The side tins have no holes for the plug wires, and the existing holes for the heat exchangers have to be plugged for proper air flow.

There is an alternative to the oil cooler setup. A thread on Pelican outlines how to backdate the 964/993 engines to use an engine mounted oil cooler. But that won't be big enough to handle a 3.6. Yo still need an external cooler with it.

4. The stock 901 transmission will bolt to the 3.6, but it is not going to last long with that much torque unless you baby it. And the stock gearing is too low for a 3.6. Plan on at least a 915 with the martin-bott conversion for mid engine use. A G-50 out of a 911 won't fit without running it upside down, and that causes problems. The bold pattern between the engine and transmission are not symmetrical, and you have to redrill the bolt holes on the transmission. The axle angles are now too extreme for proper CV joint longevity, and you have to make some kind of linkage to shift it. A boxter/cayman trans will work but requires a custom adapter plate and clutch assembly. You can see how I overcame that, and all of the things that it affected in my build thread.

5. The stock oil tank fittings are too small for the larger scavenge lines that come on a 3.6. Yes, you can backdate the fittings, or get an adapter for the tank, but that restricts the return oil flow. I just bought one of Ben's oil tanks to fix that on my big six car.

6. The stock 914-6 heat exchangers will bolt up to a 3.6, but they are WAY too small for it. Plan on spending some bucks to buy some aftermarket headers/heat exchangers.

7. The stock DME on the 3.6 engine requires some modifications to get it to work on a 914. The wiring is not setup for it, and you have to do a lot of moving of components and custom wiring. Plus the throttle body will hit the front of the rear trunk. I know others may have different experiences, but I had to cut the center portion of the intake runners, separating the top tube from the bottom. Then I was able to angle the top one down enough to clear the front edge of the rear trunk floor. You also have to fabricate an intake tube from the throttle body to the air flow meter, and use an aftermarket air filter. There is no room for the air flow meter on the back of the engine. And you definitely have to remove the torsion bars for the rear trunk and cut the safety loop off the chassis to be able to put in the throttle body.


Frankly, If I were doing an engine replacement on a factory six, I would not choose a 3.6. While it can be made to fit, it is not going to be easy. I would suggest a euro 3.2 as the biggest motor. You will still have the challenges of the transmission strength, but the rest of the stuff will bolt on to the motor. A 3.0 CIS motor is also good, with an aftermarket EFI conversion.

My build thread: http://www.914world.com/bbs2/index.php?showtopic=279084

Hope that helps!

Clay