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

[sixaddict]

Jim:
I am not an expert but to me using a Patrick style mount is better that stock six….
It spreads the mounting wider which is probably good with the additional torque generated by 3.6. The car I had and my son now has, has been using this for years…..to me it’s also easiest to install engine IMO.
Have seen a 3.6 that was autocrossed tear up a smaller set up although can’t vouch for welding.
Just my 2 cents

[SirAndy]

This might give you some ideas ...
http://www.914world.com/bbs2/index.php?showtopic=44700

(IMG:style_emoticons/default/bye1.gif)

[sixaddict]

A P S…..add stiffening before you need it due to fatigue.

[targa72e]

Engine choice and mounting is one thing. I think there are plenty of mounting options that would work fine with higher HP engine. Bigger question is do you have the appropriate transmission to back up your engine choice. The minimum I would think as appropriate for 3.6 engine would be a 915 transmission. Cost to fit to a 914 is fairly larger. All my current Porsche projects are transmission limited. The cost to go to the next level upgrade is quite large in all my cases.

john

[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

[mepstein]

If you want a transmission that will hold up to a strong 3.6, I have a Peter Dawe built Carrera trans with the WEVO side shift adapter. It was behind a Dawe built 3.6 that’s in my friends SC. Set up for a remote oil cooler. Includes Carrera axles and shifter. $14,914.

[ClayPerrine]

I found the link on the Pelican parts site for backdating the oil cooler on a 3.6.

https://forums.pelicanparts.com/porsche-911...here-s-how.html


It requires removing the cam and machining off the power steering pump drive and putting in a cam plug. So it is not a simple task.

And with the Cayman trans I had, I couldn't do it. The cooler hits the adapter plate for the transmission.

[jim dorociak]

WOW you guys are so quick to shed light on the task at hand. Clay - SirAndy, mepstain, Sixaddict, targa72e - thank you. Clay I am starting to realize either a 3.2 or a short stroke 3.2 is the best way to go. It seems you can not count on the strength of the front engine mount point on the six being strong enough. YES I am planning on a 915 transmission as that has been my dream for years. Jim

[ClayPerrine]

WOW you guys are so quick to shed light on the task at hand. Clay - SirAndy, mepstain, Sixaddict, targa72e - thank you. Clay I am starting to realize either a 3.2 or a short stroke 3.2 is the best way to go. It seems you can not count on the strength of the front engine mount point on the six being strong enough. YES I am planning on a 915 transmission as that has been my dream for years. Jim

Honestly, I don't particularly like the 915 transmission. I think they shift terribly.

I wish someone made a mid engine version of the G-50 or a Boxter/Cayman transmission with a bell housing for an air cooled motor.

Glad I could help.

Clay

[Steve]

I'm running the Martin Bott kit 916 with a rennshift on my 3.2. I agree, the shifting is more balkier than a 901/914 trans, but its no big deal, just takes a little more muscle to get it into gear, but you quickly get used to it. For me it was worth every penny. I see people are working on a kit for a boxster/cayman trans. That would be the way to go if they can mass produce it.
Otherwise, I also bought a 1995 3.6 motor and plan on using the 915 with it. I will start the install after Rennsport.

[SirAndy]

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.

I've been running the same stock 901 behind my 3.6 for over 15 years now. The only thing i'm careful with is first gear. I don't put any torque through it, no first gear burnouts. If i want to get off the line quick, i take off in 2nd gear. I can lay down 30 feet of rubber, no problem.

I also find the gearing quite nice (again, excluding first gear here). I can do 0-60 without ever shifting out of 2nd. 2-3-4 is perfect for driving around town as well as backroads and AX/DE. And cruising on the freeway in 5th is just right. And then you put your foot down and it will smoothly pull all the way up to 135.
(IMG:style_emoticons/default/popcorn[1].gif)

[Steve]

On another note... I had Dr. Evil build me a 914 trans for my SBC. Stock 2nd, O for 3rd, X for fourth and HA for 5th. This trans is awesome and feels stock, but much lower rpms in each gear. For 1/4 of the price of a 916 trans, it would be a nice option for a 3.6, but you only have 4 gears and I would not beat it. You will also need heavy duty CV's. Sir Andy has been running a 914 trans for years with no problems.

[mepstein]

WOW you guys are so quick to shed light on the task at hand. Clay - SirAndy, mepstain, Sixaddict, targa72e - thank you. Clay I am starting to realize either a 3.2 or a short stroke 3.2 is the best way to go. It seems you can not count on the strength of the front engine mount point on the six being strong enough. YES I am planning on a 915 transmission as that has been my dream for years. Jim

Honestly, I don't particularly like the 915 transmission. I think they shift terribly.

I wish someone made a mid engine version of the G-50 or a Boxter/Cayman transmission with a bell housing for an air cooled motor.

Glad I could help.

Clay

You haven’t tried one that was properly built. (IMG:style_emoticons/default/biggrin.gif)
Eric has the same trans in his big kahuna PMS built 3.6 as what I’m selling and here’s what he says:

[Lucky9146]

Great Thread here, and I'm all ears with my current 3.0 /901 setup.

Was going to go 3.0/-915 Martin Bott I have, but now considering the 3.6 I have instead.

The 3.6 was destined for a different project.

I've seen Eric's car and It's a beast!!!!

A lot of good info on this thread.
(IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/white914.jpg)

[ClayPerrine]

You haven’t tried one that was properly built. (IMG:style_emoticons/default/biggrin.gif)

I have driven and built lots of 915 transmissions, and even ones that were rebuilt by Porsche. None of them really shifted well. That's why Porsche designed the G-50.

The 915 was the end of the line for the Porsche in house designed syncromesh. The G-50 used the Borg-Warner syncromesh. That's why the G-50 is so much better than the 915.

[Dr Evil]

Yup, always comes down to the transmission. What good is a nearly motor when you inhibit it with inadequate transfer of power to the wheels?
If you go 915, PMB is selling the conversion kit in the states, or contact Martin in Germany, but you will need to send in some parts to be modified, so domestic is nice from a trusted source. I’m not a fan of the WEVO/Velios tail shift design. It takes a lot of refining to get it to work and adds linkages and slop points to the set up. It works, but I think the side shift conversion is superior. Bring $$$. The labor to install, or rebuild and install isn’t bad through me, the parts are the main cost driver.
If you can source a 930 box, that would be a neat one to convert as the gears are beefy (but it’s a 4 speed). Currently rebuilding one now. 901 first next to 930 first.


930 slider next to 901 slider. The 4,5 gears in 915 are the same dimensions as the ones in a 901, same with the sliders. In a 930, everything is thicker.

I like the idea of a boxter/Cayman tranz being used. I don’t like having to be mindful of power utilization.
Another option would be Mendeola $$$$.

[mepstein]

We have a Ruf 5 speed 930 but I doubt my buddy will let me convert it to run backwards
Peter Dawe worked his magic on my WEVO trans so that must be why it works so well.

[JmuRiz]

We have a Ruf 5 speed 930 but I doubt my buddy will let me convert it to run backwards

(IMG:style_emoticons/default/wub.gif)

[Steve]

We have a Ruf 5 speed 930 but I doubt my buddy will let me convert it to run backwards
Peter Dawe worked his magic on my WEVO trans so that must be why it works so well.

The 930 gear boxes I have seen in a 914 required you to run it upside down, cut the trunk up and use a cable shifter. Plus the 930 trans is very costly. For me it was more trouble than it was worth.