What kind of gearbox to use on high power F6 ? Options

[speedsterms]

Hi all,
I leave in France.
I use to have some 911 (3.2l, 993RS Club Sport, 993 RSR, 993 c2)
today I am on another project : 917K Replica.
with a mid mounted engine - the reason why i am asking my question here-

My engine will be a high rev/high power aircooled 3.6l.

I have planned to mate the engine to a 915 gearbox with flipped R/P. but I was told by my mechanic that the 915 will not handle the torque. even if I improve oiling and cooling and add a wevo bearing retainer.

I had a G50 (which I swap to the 915) as it was not usable. impossible to flip R/P. and flipping the gearbox is not acceptable to the CV joint (too much angle) .

I wonder if any one of you have tryed to install a cayman 987.2 gearbox (G8740 to be precise, not the fisrt gen) on an aircooled flat6 ?

Is there any kit available ? (adapter plate)

[ClayPerrine]

Hi all,
I leave in France.
I use to have some 911 (3.2l, 993RS Club Sport, 993 RSR, 993 c2)
today I am on another project : 917K Replica.
with a mid mounted engine - the reason why i am asking my question here-

My engine will be a high rev/high power aircooled 3.6l.

I have planned to mate the engine to a 915 gearbox with flipped R/P. but I was told by my mechanic that the 915 will not handle the torque. even if I improve oiling and cooling and add a wevo bearing retainer.

I had a G50 (which I swap to the 915) as it was not usable. impossible to flip R/P. and flipping the gearbox is not acceptable to the CV joint (too much angle) .

I wonder if any one of you have tryed to install a cayman 987.2 gearbox (G8740 to be precise, not the fisrt gen) on an aircooled flat6 ?

Is there any kit available ? (adapter plate)

I put a G86-21 behind my 4.0L engine (3.6 with an overbore). It is definitely a challenge to get the transmission hooked to the engine. But it can be done.
You can read about it in my build thread here: http://www.914world.com/bbs2/index.php?sho...79084&st=80

Making an adapter plate is easy.

The biggest problem is the clutch. The 964/993 engine uses a pull clutch, that is the clutch pulls on the throwout bearing and pressure plate to disengage the clutch. The Boxster/Cayman transmission uses a push clutch, the throwout bearing pushes in on the pressure plate to disengage the clutch. Adapting it is the biggest problem.

The second biggest problem is the starter. The air cooled engines all had the starter mounted to the transmission bell housing. The water cooled engines have the starter mounted to the engine. So when you hook an air cooled engine to a water cooled transmission, you end up with no place to put a starter. My solution is to cut a notch in the bell housing of the transmission and build a removable starter mount that attaches to the adapter plate.


You are welcome to copy anything I did.

Good luck and post pictures of your car when it is finished.