8BA Pressure Plate Swap
 

Good day.
I just finished overhauling my 8BA with C1BA block which bolts onto what I suspect is the original 3 speed column shift transmission that the '40 deluxe ford came with possibly 78 type. When I nip the bell housing bolts I get a solid metal to metal interference. I suspect its from the new diaphragm type pressure plate that I fitted. It used to have the old 3 finger type pressure plate. The new pressure plate is from a F250 and covers the whole flywheel so I think its a 11 or even 12'' unit. Does anyone have experience with this arrangement? The block flange bolts directly to the bell housing. I've seen other arrangements where they have a cover plate that goes in between the two mating faces which is probably all I would need to get rid of the interference.

Re: 8BA Pressure Plate Swap
 

Any reason to be using such a large pressure plate? What is it in? Flatheads do not use a plate between the engine and the bellhousing like modern engines.

Re: 8BA Pressure Plate Swap
 

This is what my local clutch specialist could find locally. Finding Flathead parts in SA is nearly impossible. I saw the same plate arrangement on this conversions (See photo attached).

Re: 8BA Pressure Plate Swap
 

That does not look like a flathead block. I'm sure you can build a special spacer plate, but this sure looks like doing things the hard way. Unless you are putting this engine into a large truck or pulling/carrying heavy loads that is to large a clutch and pressure plate. In a fairly lightweight car you would want a 9 inch setup. The larger the diameter of the clutch/pressure plate the slower the acceleration, so it depends on the application. For performance you would want a smaller diameter, for a slower moving heavy load vehicle, a larger diameter.

Re: 8BA Pressure Plate Swap
 

What do you mean " when you nip the pressure plate bolts ".

Re: 8BA Pressure Plate Swap
 

Literally the last turn before the bolts are tight is all it took for the interference to occur. I found the problem last night. I removed the starter and half circle plate and managed to see just enough to realise that the interference was caused by one of the bolts connecting the tranny to the bell housing. They were a bit long and touched the new fatter pressure plate. I put a shorter bolt in and voila...sorted. I only removed the bolts between the bell housing and engine block. Never thought about the other bolts.

Re: 8BA Pressure Plate Swap
 

There you go. I am glad you found the problem. Some time we have to look at the simple first. But the word NIP took me for a loop. LMAO. Jim.t.