Bell housing assembly on ZFDS25 for RCR GT40

[Jean-Marc]

The ZF gear box is assembled on the bell housing with 7 bolts 3/8. 5 bolts are accessible from outside on the gearbox, but the problem is the 2 top ones (green circle) they are coming from the inside of the bell housing.
When you remove the gera box from the engine, it is require to remove the bell housing in the same time. And in this case, to access to the bell housing it is necessary to deassemble all the exhaust pipes that bloc the top of the bell housing.
Alos it is nessary to remove the starter motor, and to liftup the back of the engine to clear the starter bump on the seide of the belle housing.
If I considere that the bell housing is hold in place by the 2 bolts (red circle) assembled on the rail plus the 5 other bolts assembled on the engine, also there is no bolt at the bottom of the engine to keep the bell housing in place versus the engine. All those bolts are enough to keep in place the bell housing and the gear box, without to keep the 2 bolts coming from the inside of the belle housing.
For this reason but to still use the guiding function of the 2 bolts, I am thinking to replace the 2 bolts (green circle) by studs with a head that will fit the diamter of the hole to hold in place the bellhousing at least in rotation.
Like this,,the beal housing remains on the engine bloc when it is necessary to remove the gaerbox. No more need to deassemble all the exhaust pipes from the engine and no need to lift up the back of the engine because of the starter bump on the side of the bell housing.
Does anybody made this change allready, do you think it si stupid or risky ?

 

[Michael]

Jean-Marc, that is a common mod for the ZF application. I recently did the mod on my car. I replaced the bolts with studs and made some covers to prevent dropping anything into the bellhousing.

 

[Jean-Marc]

Michael, very clever, from what I see, you have threaded studs and you put a screw that you can acces from the openings, is it right ?
I was thinking in another way, in my mind, I wanted to use a stud with one end threaded that a put inside the gearbox and the other end unthreaded use only to guide the bell housing. In this case I have no positive assembly.

 

[Michael]

That’s correct J-M, you can attach nuts to the studs through the openings and securely fasten the ZF to the top of the bell housing.

 

[bryanf]

The Quaife bellhousing includes the access ports.

 

[Bill Kearley]

I wanted to make that mod as well Jean. I was a little uneasy with it. For me I'd have a hell of a time removing the bell with the trans because of the cross member under the bell ........ I cut and modified it in order to have the install as low as possible. In a a CAV.

 

[Jean-Marc]

Bryanf, the opening on the Quaife bell housing are rounded with stifeners, I think this is more secure than the cut that Michael did, but it is purely a view of my mind, the behavior is probably not impacted by the 2 openings anyway.
Compare to the bell housing of the Ford big bloc the design of this ones are fare to be optimized for strength because the bottom of it is completely open, but it is probably compensated by the short distance between the gear box and the engine, and also by the top rail where the gear box is screw in, that take the bell housing in sandwich