Engine / gearbox sandwich plate.

pjbs · Jun 23, 2020

Help please, what is the set up on the Mk1 race cars ? The Parts catalogue shows a lower plate. (part No 1)
Is there an upper part to this, I cannot find one, so does the bellhousing bolt direct to the engine ?

Thanks, Peter.

jac mac · Jun 23, 2020

pjbs said:
Help please, what is the set up on the Mk1 race cars ? The Parts catalogue shows a lower plate. (part No 1)
Is there an upper part to this, I cannot find one, so does the bellhousing bolt direct to the engine ?
View attachment 107711
Thanks, Peter.

Going by that drawing it would appear that a sandwich plate is not used. I hope the #1 plate is doweled to the bell housing as it index's the starter to ring gear engagement dimension which is fairly critical.

brianstewart · Jun 23, 2020

There is no upper part to plate 1. It is essentially a cover plate to close off the bottom of the bellhousing.

brianstewart · Jun 23, 2020

Bare plate.

pjbs · Jun 24, 2020

brianstewart said:
Bare plate.View attachment 107713

Hi Brian, Thanks for confirming my thoughts, and providing useful photos, regards, Peter.

Doc Watson · Jun 25, 2020

I have just assembled a 'dry fit' of my engine so I can check the fit of the lower bell housing to my chassis..... my cover plate covers the whole bell housing..... there is even a vid.....

17 mins 19 secs it makes an appearance......

It still needs a vent hole in the bottom to pick up air when running and it will be ss mesh same as the top and bottom cover plates. It does mean that the gearbox is 2mm further back due to the plate being between the engine and bell housing.

spud · Jun 25, 2020

what's the accepted wisdom with regards to venting on the bottom? I just made a solid block-off cover and fitted it, I want to make sure any random oil drips from the bottom of the engine don't their way into the friction surfaces of the clutch and flywheel. The Porsche bell housing has an opening on the side to vent, though it probably won't feed fresh air to the clutch.

pjbs · Jun 25, 2020

Doc Watson said:
I have just assembled a 'dry fit' of my engine so I can check the fit of the lower bell housing to my chassis..... my cover plate covers the whole bell housing..... there is even a vid.....

17 mins 19 secs it makes an appearance......

It still needs a vent hole in the bottom to pick up air when running and it will be ss mesh same as the top and bottom cover plates. It does mean that the gearbox is 2mm further back due to the plate being between the engine and bell housing.

Hi Andy, I have "liked" your video, It did make me check what the original set up was, hence the question above.
I have seen the cover plate on the Cushman site. but I think it is easy to make.

Thanks Peter

Doc Watson · Jun 25, 2020

I think some form of venting is desirable, if you have a vent on the cover plate and also one on the top of the bell housing then it will allow the air to flow freely even if the bottom bell housing plate is 'solid'.

I think Safir make a bell housing with a cast in duct to 'scoop' air into the clutch area... trying to find a photo if it.

pjbs · Jun 25, 2020

spud said:
what's the accepted wisdom with regards to venting on the bottom? I just made a solid block-off cover and fitted it, I want to make sure any random oil drips from the bottom of the engine don't their way into the friction surfaces of the clutch and flywheel. The Porsche bell housing has an opening on the side to vent, though it probably won't feed fresh air to the clutch.

Hi Tom. Just additional cooling I guess,

regards, peter.

Doc Watson · Jun 25, 2020

here it is....

the scoop is at the top of the bell housing.

Bellhousing Assembly

Plate J Items 10,11,& 12 Part # GT40/P/7/5307/ASSY The Safir GT40 Spares, Limited bellhousing assembly includes the fully machined, T-356 aluminum bellhousing that mates a small block Ford engine block to a ZF 5DS25/1&2 gearbox. It is also available machined to mate to the ZF 5DS25/0...

store.gt40.com

pjbs · Jun 25, 2020

Doc Watson said:
I think some form of venting is desirable, if you have a vent on the cover plate and also one on the top of the bell housing then it will allow the air to flow freely even if the bottom bell housing plate is 'solid'.

I think Safir make a bell housing with a cast in duct to 'scoop' air into the clutch area... trying to find a photo if it.

Andy, I have the Safire Bell housing, Thanks, Peter.

pjbs · Jun 25, 2020

Doc Watson said:
here it is....

the scoop is at the top of the bell housing.

Bellhousing Assembly

Plate J Items 10,11,& 12 Part # GT40/P/7/5307/ASSY The Safir GT40 Spares, Limited bellhousing assembly includes the fully machined, T-356 aluminum bellhousing that mates a small block Ford engine block to a ZF 5DS25/1&2 gearbox. It is also available machined to mate to the ZF 5DS25/0...

store.gt40.com

View attachment 107733

Hi Andy, Yes that is the one, I cut off the casting at the top to put in a similar vent to the bottom. Thanks, Peter

Doc Watson · Jun 25, 2020

Mine was from Paul Flemming, also notice its 4 bolt to the gearbox as I have a ZF-0

pjbs · Jun 25, 2020

Doc Watson said:
here it is....

the scoop is at the top of the bell housing.

Bellhousing Assembly

Plate J Items 10,11,& 12 Part # GT40/P/7/5307/ASSY The Safir GT40 Spares, Limited bellhousing assembly includes the fully machined, T-356 aluminum bellhousing that mates a small block Ford engine block to a ZF 5DS25/1&2 gearbox. It is also available machined to mate to the ZF 5DS25/0...

store.gt40.com

View attachment 107733

PS , Andy, It is not a scoop at the top, just a casting with GT40 on it. It was cut off by the Gentleman who sold me the casting, I worked on it to put the top vent in. Regards, Peter.

Doc Watson · Jun 25, 2020

Sorry my mistake I assumed it was a scoop. I stand corrected (said the man in orthopaedic shoes).

pjbs · Jun 25, 2020

Hi, This is another shot of my Safir Bell housing, note arrows pointing to 2 small threaded holes. To hold the cover plate I guess.

Also 2 large 1/2" holes at the bottom. No sure what these are for . Brian's cover plate photos above shows the right hole. The other seems to be redundant.
Jac Mac's post suggests indexing, and Brian's photo show the right hand bolt but it is not clear what the detail is.

Comments ?

Regards Peter

manta22 · Jun 25, 2020

Dowel pins?

JIMMYMAC · Jun 26, 2020

Dry sump 260 / 289 ?
I have always thought that those holes in these newer castings were redundant detailing off the original ZF 4-bolt bell housing 7/5351 which was used in the days of the DOHC 255 engine and this had a full length and width alloy dry sump. The casting has two screw holes at the bottom of the rear end.
The Hewland bell housing for the 255 engine has a similar two holes.

Then again I am assuming the other bolts holes on both engines had the same geometry !

wolodymyr · Jun 26, 2020

Hi Andy, I just enjoyed your videos and it was good to see the man behind the story. Regarding your comments on steel versus alloy timing cover, you might like to see the weights that I measured when I changed mine. Look forward to the next video.

	Iron	Al	Saving
Heads	2 x 26.4	2 x 13.5	25.8
Manifold	18.6	8.3	10.3
Timing Case	6.4	1.5	4.9
Total	77.8	36.8	41

Dave

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