2.7/901 trans. incompatable??
 

Hello all, I am a first time 911 owner and pelican member. I have recently picked up a incomplete 67 911 project car on the cheap. The topside and interior were done by p.o. but they never finished the engine installation and repaired the floorpan with fiberglass!! I have just finished the floorpan replacement and misc. other rust areas and am starting on the engine. I have the original 2.0 (out, looks rough but turns over) and a 74 2.7 w/webbers (in, does not start, going to rebuild/refresh). The P.O. never drove the car with the 2.7 because of a clutch problem.
My question is if the 2.7 is compatable with the original 901 trans.? Do i need a diff. flywheel or clutch kit? Any input or replys appreciated.

thank you.


i know i will hear that i should just put the 2.0 back in... but the car has RS flares, tea tray and aftermarket wheels. i might have some clean 15" fuchs for sale soon.

I am putting in a 75 2.7s in my 67 912 with a 901 5 speed. I'm using a clutch and flywheel from a 68-69 911.

I have a 2.7/901 mix - Butch Stokes Automotive of Ft. Lauderdale Florida did the conversion- they may be able to give you details?
rgds Ben

the 901 is useable with a 2.7, but it suffers eventually. the bearings holding the shafts in position are small, the bearing retainer in the intermediate plate is inadequate where it holds the mainshaft bearing, the ring and pinion is small, and the differential carrier is weak. it will work for a while if you don't pound it.

2.7 to 901; popular!
 

I'm going to do just the same very soon! I am buying a nice 2.7 from a friend, and put it in my '69 'T' 911 car.
I have already researched it, and know at least 2 guys who are using this combo, and they like it a lot.

I drove a 912 with 2.7 engine for two years. It had the original 901 tranny from the 912, and there were no problems. I honestly don't think that this set-up is so bad for the 901, since long before the tranny takes serious strain, the rear tyres loose grip. Assuming you keep the original (narrow) wheels of the earlier car.

I respectfully disagree with John Walker. The 901 is more than handy for HP up to about 250+. John (Otto) regularly runs 901s in his 914-6 with about 300HP...

-Wayne

Yes he does, but I bet he wouldn't take $5000 for the tranny out of his race car. I wonder what he has done in there besides gear set changes. On another note: Many 914 guys have the 901's that their cars came with coupled to all different kinds of six cyl motors.

As far as I understand it tranny's should be rated by torque -- not HP. A hypothetical 2.0 making 300 HP at 10000 RPM should be fine with a 901. A 3.8 making 284 lb-ft in a 3000 pound car will most likely destroy it in a few thousand miles without getting close peak HP. It sounds like a 901 won't grenade with a 2.7 or larger on it, but will it last for 150k-200k miles under all sorts of conditions? I doubt it. This is why Porsche went to the 915.

I have a carbed 3.0SC backed up by a 911 (late style 901 with pull clutch) and it works great BUT, my car is light with fiberglass bumpers and fenders and minimal interior it's roughly 2000lbs. I'm running SC flares and 8" Fuchs with 245's in back and since I have a newly rebuilt 911 trans ready to go in I was pretty hard on the one in the car this past summer trying to find the weak points but never broke it. I did however wear the stock 911 clutch out right before I put the car away for the winter. I'm a former drag racer so I am hard on clutches and trannies, I'd have to think a 901 would last just fine behind a 2.7 if the car was light enough and clutch-dropping wheelspining launches where avoided, drive it smooth and I see no reason it won't survive. It is also possible to upgrade the 901 with a steel intermediate plate and external oil cooling, two things which I'll probably do the my rebuilt tranny before installing it. With the increased torque it's critical that you have the score washers on the halfshaft bolts, I even went so far as to drill and lock wire them in place. While a 915 is probably a better candidate it's not the easiest install into an early 912 since you'll need adapters for the halfshafts, 915 shifter and 915 clutch/flywheel. I believe some minor cutting of the tunnel is also necessary but I'm not sure. Good luck with your project, did you get the short geared 7:32 R&P?

Good point about the torque - you're right, the total HP is a poor measurement to use for a tranny...

-Wayne

actually i was more in question of the correct parts needed..i have 2 complete clutch assemblys, a 67 and a 74, but i dont know which one to use or what the difference is between them.

Kennedy Eng. Products and Ptrick Motorsports make clutch kits to adapt later engines to the 901 tranny. Check w/them to see if you need their kits.

Go easy in 1st gear and the 901 should last a long time.

You need a 215mm clutch and flywheel from a 68-69 911 . But to give you a complete answer just check out my posts on this thread .

http://forums.pelicanparts.com/porsche-911-technical-forum/93097-move-901-915-tranny-my-69-t.html?highlight=2.7+901

Kurt Williams

Hmmmmm......
 

Which weighs more, the flywheel off a stock 2.0 liter engine, or one from a '74 CIS 2.7 liter?

Does anyone know?

The 2.0 liter probably weighs more but its got to be close. BTW I have a flywheel,clutch,and pressure plate from a 69 2.0 if your still in need.

Kurt Williams