Propshaft clearance

[lomondbob]

Just installed engine/box - never been so stressed out in my life with all that weight hanging around in the air! Anyway, a small question. The gearbox mount sits on the Dax supplied spreader plate which means that the front UJ has a clearance of no more than 2mm above the small chassis cross member. If I add a 2mm shim between the box mount and the plate to raise the box I can gain a clearance of just over 6mm. This still leaves enough thread on the mounting to thread nylocs with 2 threads showing. Is a 6mm clearance OK? I think so but just need confirmation. Thanks chaps.


Bob

[craggle]

Silly question, But have you bolted the spreader plate to the top or the bottom of the plates welded on the chassis?

Craig.

[lomondbob]

Craig. I took Pete Walker's advice and located the plate on top of the chassis plates. I have yet to bolt down although drilled two holes on each side of the plate in readiness. It all looks fine but I'd like to ensure the clearance is OK. Thanks.


Bob

[craggle]

OK. I was wondering if you had the plate on the bottom which would lower it considerably.

It still sounds very close though. What gearbox and mount are you using. Does it look as if the propshaft will have to go uphill to mate with the diff?

Craig.

[craggle]

Just another thought but you don't have to add spacers under the mount itself. You could make a couple of spacer plates to put in between the spreader plate and the chassis plates and use slightly longer bolts.

Craig.

[lomondbob]

Craig. It's a Tremec TKO500 supplied by Brian Nichols. Dax supplied the mount. DAX also supplied the propshaft. There is the usual prop offset both vertically and horizontally and I accept all this. Good idea of yours to raise the plate instead of shimming it. I suppose I could do either but just need to be sure that the minimum clearance between UJ and chassis is OK. I reckon 6mm will do as I am sure the greabox will move very little in any direction once all is bolted down and the rubber mount will not give much. So 6mm should be more than adequate. I'm just a bit wary of SVA man and what he might think! What is your clearance?


Bob

[craggle]

Same gearbox as me and supplied by the same company. My mount came from Re-Power as well though.

I have taken some pictures of the underside of my car for you to look at. Hard to tell what the clearance is but it looks a bit more than 6mm.

Are you building the standard or De-Dion chassis car? Mine is the standard XJS based car. The De-Dion chassis may be different in this area?

Here is the mount I used. Mount

Craig.

[Clarkson]

Originally Posted by craggle

Same gearbox as me and supplied by the same company. My mount came from Re-Power as well though.

I have taken some pictures of the underside of my car for you to look at. Hard to tell what the clearance is but it looks a bit more than 6mm.

Are you building the standard or De-Dion chassis car? Mine is the standard XJS based car. The De-Dion chassis may be different in this area?

Here is the mount I used. Mount

Craig.

You wanna start driving that car M8! Looks to clean under there!

[dave]

Tip for the day.
If you mount the cross member plate on the top of the chassis mounting plates the only way you will ever be able to remove the gearbox will be to remove the transmission tunnel.
Having a removable transmission tunnel is not a great deal of use either as the backbone bracing on the chassis means the gearbox cannot be removed through the inside of the car, so the only way out would be to pull the engine out first.
So, to sumarise.
Plate on top:-
Box won't be able to drop down.
Box wont be able to slide forward.
Tunnel will have to be removed (Eventhough the box won't be able to come out through the cockpit).

Plate on the bottom:-
Box can drop down and be withdrawn with or without the engine through the engine bay. (No need to remove seats, seatbelt fixing, dashboard and lump about a big heavy oily item through the interior of the car)

The problem with option 2:- you will have to fabricate an 8-10 mm spacer to go between the box and the mount to make up the loss of height due to mounting the crossmember on the under side of the chassis mounting plates.



Feet for dancing boys.