901 trans on 911SC 204hp engine

[jon sigurdsen]

Hi

1. Will a 901/902 (4speed) transmission bolt on to a 911sc (1982 Euro) engine, or do I have to change the clutch etc?
2. Will the 901 handle the torque from the 3.0L with normal street use (not track)?

thanks

Jon S

[soren.911]

At least put on a reinforced side cover.

California Motorsports Porsche 901 911 914 transmission section

[Matt Monson]

You will have to change the flywheel and clutch.

4spd will be a better option than 5spd because it doesn't have the cantilevered 1st gear. Just remember if you shop for replacement ratios that 2nd in a 4spd is really a 901 3rd gear and 3&4 are what are normally 4/5 gears.

[jon sigurdsen]

Hi

Thanks for the replys.

which flywheel and clutch do I need?
The 1982 engine has the bigger 9bolt crankshaft, so I don't see how a different flywheel will fit the engine.

Thanks

Jon

[Grady Clay]

Jon,

You will need the clutch disc, pressure plate and release (TO) bearing from the ’70-’71 2.2 liter. You will also need to replace the transmission TO bearing guide tube with the longer one from the type 911 (’70-’71) transmission. Make sure the two fingers on the clutch release fork mate properly and are lightly preloaded with the indent in the TO bearing so they can’t come out.

Using a 901 transmission with a 3-liter is a temporary solution – at best. The 901 (type 911 actually) was highly stressed even with 2.2 liters.

I recommend you find several core 915s and build yourself a ‘like-new’ example.

BTW, what year chassis?

Best,
Grady

[jon sigurdsen]

Hi!

Thanks For Your Answer!

I have a 915 aswell (1973). Thing is that the Chassi is 1966 but it has been converted to a LWB. Therefore the 915 will not fit correctly in the tunnel, So I thought I might use a 902 trans that was originally for the car, and has been i this car with this setup, only then with a 2.4 engine.

I have decided to go with the 915 for this car and modify the tunnel.

Thanks alot

Jon S
Norway

[Walt Fricke]

John - you are correct, you can't bolt a 6 bolt flywheel to your 9 bolt crankshaft. But I am pretty sure you can use your existing flywheel and bolt an early pressure plate to it - the later clutch plates, and hence the PPs, are larger in diameter, are they not? But I think the 9 bolts which hold the PP to the flywheel are the same pattern/dimensions? Maybe not. You should be able to drill and tap new mounting holes. Might also be a problem attaching the ring gear, but you could fabricate a spacer (or turn one using a junk later PP, preferably an aluminum housing one to do this).

You will need an early clutch disk, as the spline count on the mainshaft of the 901 is different from what was used with the 915s.

Because the 901 is set up for a push clutch, and the 915 for a pull, you can't just use the 915 pressure plate with an early clutch disk.

Though there are other options. One would be to machine the 901 box to use the 911 clutch release mechanism. The 911 PP bolts right up to the flywheel you have, so no issues there. The 911 uses a pull pressure plate, just like the 915. The 911 release mechanism is a kind of a factory kludge (how do you pull on a cable and use it to push something? Well, Porsche figured that out!).

In the US, a guy would contact one of the aftermarket clutch/flywheel shops. I'm pretty sure they make a flywheel with 9 bolts but otherwise machined like the 901. Or something else to convert.

And I don't know about the pilot bearings - obviously something to make match.

[retro356]

I have been running a 901 with my dyno 280hp 3.0 in my 914. With occasional track days. Jeff Gamroth built the engine. He is more concerned with the clutch. He tried several applications to get enough clamping power. So far so good.