Later motor onto 901 trans? Any poblems?

[KS Carrera]

If installing a later (911SC) motor in a car with 901 trans, do you need to change anything, such as clutch, flywheel etc? Thanks.

Oops, just noticed I said 'poblems' in the title – I mean 'problems'!

[super9064]

I have a 901 (technically a type 911, 1971) matted to a 3.2. You will need a new fly wheel, and I'm pretty sure a new clutch. I would also consider reinforcing it with the aftermarket intermediate plate.

If you do a search on Pelican you will find a number of threads on the subject. In a nutshell, the prevailing wisdom is that the 901 is not strong enough and will eventually fail, that is countered by those on the other side, that all those V8 914s use a 901 and so did the factory 911STs.

My opinion is that if you drive sensibly, you should not have a problem. That said had I not just rebuilt my 901, I would have gone with a 915.

[edmayo]

What year 901 you talking about? It makes a difference.

[KS Carrera]

Ed, I apologise for my lack of useful info. The car is a 1966 912, but whether the trans is original or not, I don't know. The car is in SoCal, ready to be shipped, so I don't currently have direct access to it. All I now is that the trans has the following ratios:

1st A 11:34
2nd F 18:34
3rd M 22:29
4th S 25:26
5th X 28:24

[edmayo]

Keith, the reason I asked which 901 is that a 70-71 901 is already set for a pull type clutch which is what the SC has, any other year 901 isn't. That will be the biggest obstacle, since the SC uses a 9 bolt flywheel you can't backdate the clutch assembly to the earlier type. Maybe Kennedy clutch has a push type clutch that will bolt on a SC flywheel?

[Flieger]

In the interest of completness, the 70-71 is actually a type 911, not a type 901, though it is very closely related.

[super9064]

In the interest of completness, the 70-71 is actually a type 911, not a type 901, though it is very closely related.

Flieger, how much stronger is a type 911 than a 901?

[KS Carrera]

I believe the trans is from '66. So, from what I understand, I would need a flywheel from Kennedy or Patrick Motorsports (or whoever else) which allows the early clutch set-up to be used on a later engine. I could live with that (whether my bank balance can will be another matter!).

[Flieger]

Well, Grady or some other expert would be better able to answer that, but I believe the 911 can take the later and stronger 915 differential (and LSD) while the 901 cannot. The gears themselves are interchangable, though. It is doing fine with my 2.7 RS spec.

[Scott Clarke]

The 911 isn't really stronger than a 901. It has a mag case in lieu of aluminum. First and second gears were slightly wider with the 911, if memory serves. With the exception of output flanges of some versions, 901 and 911 diffs are interchangeable.