8BA and 39 trans mating questions

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nb141fd

Senior Member
I'm trying to mate a 39 box to my 1950 8BA and find that the 1 3/8" input shaft is not going to work with my 9 1/2" clutch. The 9 1/2" takes a 1" OD input shaft. From researching it looks like I will have to get a 9" or 10" early clutch and pressure plate to make this marriage work. Does that sound about right?

If I go with a new 9" or 10" clutch and PP will either work with my 8BA flywheel without having to drill new holes?

TIA

Tony
 
The correct combination of parts to match an 8BA flywheel to an earlier transmission is:


10” Pressure Plate PN# 19a-7563 ’46 -’48 car or ’46 -’52 pickup
10” Clutch Disk PN# 51a-7550 ’46 -’48 car or ’46 -’52 pickup
Throw-out Bearing PN# 78-7580




Lonnie
 
Lonnie, thank you very much. Not only the answers to my questions, but part numbers to boot! I love this forum.

Tony
 
Lonnie gave you good part numbers. However, the 10" pressure plate will not bolt right up to your flywheel (which is drilled for the 9.5" pressure plate). You will either have to have your flywheel redrilled or find a good used flywheel from a 48-52 pickup truck that had the 10" clutch and pressure plate in it.
 
A 49-51 Merc flywheel , pressure plate and clutch will also work. The clutch and pressure plate are both 10 inch.
 
I had the same problem with my 53 Merc. 9 1/2 " set up. I called Fort Worth Clutch and for little money he sent every thing I needed for my 39 trans. and 9 1/2 clutch. He did say I needed a wide throwout bearing with this setup. FYI
 
If you have a light body car, a 9 inch Long type clutch will work just fine. Heavy cars or trucks might like a 10-inch Long type better. Most any machine shop can index and drill for whatever clutch you decide on. The Mercury Borg & Beck clutch works too but is an even spacing of 6 bolts that are 3/8" instead of 5/16" shank. The Long type clutches are easier to source these days for cores and such. Ft Wayne clutch is a good outfit to get your clutches overhauled by when in the need.
 
I had problems with the FW 9 1/2" clutch and the 1 3/8" 39 trans. shaft. The TO bearing carrier intefeard with the inside circumference of the pressure plate when depressed and the clutch fingers would also rub on the TO bearing carrier. No problems with 10"
 
The operning on the 9.5" PP is smaller than the big spline types. They would have to change the fingers in a 9.5" PP to work too. The disk hub swap is no big deal but the T/O bearing change might be. I'd make sure they had stuff to work right before I ordered concerning the problem with the info from the last post #9.
 
nb141fd, Stick with the recipe of parts I stated in post #2. You'll have to find an 8BA flywheel drilled for 10" or have yours drilled at a machine shop. If you shop around for a flywheel on craigslist or whatever, [FONT=&quot]An 8BA 10” flywheel measures 3 1/8” C/C between the paired holes and 7 7/8” apart between the pairs.

Lonnie
[/FONT]
 
What is your flywheel between the 2 holes 3" OR 3 1/8"
If you have 3 1/8" you can use 10 or 11 cutch and then use a truck disk for a 10" ford and throw-out bearing.
If you have 3" spacing use fort Wayne kit use get all the parts you need with 9 1/2 PP and 9 1/2 disk 1 3/8 spline.
I just went thru that with 53 8rt and that trans uses 1 3/8 clutch and the trans was 39 case. Macs clutch 48-13431-1
PP 48-12199-2 and throw-out bearing 48-29469-1
 
To some extent the way you want to go depends on what you are putting it in and what you are wanting to end up with. Is this a light weight somewhat performance type vehicle or a heavy car just putting around or a even heavier truck pulling stumps? Do you care about acceleration? Do you care how heavy the clutch feel is to shift?
 
George/Main thanks for the advice. The cc distance on my flywheel is 3" so I think I'll go with the Fort Wayne package. Of course I will talk to them about the concerns Jim Haskins raises before purchase.

Tony
 
If you have a pressure plate you may only need a disk ft Wayne has 9 1/2 clutches or you maybe just use a 9" They sell that kit and it works. Use a throwout bearing from a 41 to 48 car
 
George, I have an 8BA pressure plate (9 1/2") but I thought that was part of the problem. Someone had mentioned something about the fingers on the 9 1/2" pp being too long and not allowing the throwout carrier to pass without interference. I figured that in the kit Fort Wayne might have adjusted the fingers on their pp to overcome this interference.

Tony
 
Slightly expanded list:
'49-53 wheels

11" truck...disc and pressure plate fit right up to '39...common wheel, rather heavy assembly
10"...pickup, heavy duty Ford passenger...just use '48 Ford disc and PP, bolt together
9 1/2...most cars...requires custom fingers as interference is a real possibility or redrilling for different plate
'49-53 Merc...must use '49-very early '51 pressure plate, which is becoming rare, this combination bolts right into early Ford. '51-3 has long fingers for small throwout. I have seen some wheels drilled for both Merc and Ford 9 1/2. There is allegedly a modern replacement for the rare PP, but I do not have clear information.
Aftermarket flywheel is always an (expensive) option, as is redrilling whatever you have to take early Ford plate and disc.
 
nb141fd said:
George, I have an 8BA pressure plate (9 1/2") but I thought that was part of the problem. Someone had mentioned something about the fingers on the 9 1/2" pp being too long and not allowing the throwout carrier to pass without interference. I figured that in the kit Fort Wayne might have adjusted the fingers on their pp to overcome this interference.

Tony
Click to expand...

The kit FT Wayne sells works as a kit 201388464074 ebay
The throw out bearing on a 48 measure 3 1/2 od and the smallest about 1/2" each side would be 2 1/2" the fingers must be about 2 1/2 or less.
Fully disengaged must be no more then 3 1/2"
 
Bruce Lancaster said:
Slightly expanded list:
'49-53 wheels

11" truck...disc and pressure plate fit right up to '39...common wheel, rather heavy assembly
10"...pickup, heavy duty Ford passenger...just use '48 Ford disc and PP, bolt together
9 1/2...most cars...requires custom fingers as interference is a real possibility or redrilling for different plate
'49-53 Merc...must use '49-very early '51 pressure plate, which is becoming rare, this combination bolts right into early Ford. '51-3 has long fingers for small throwout. I have seen some wheels drilled for both Merc and Ford 9 1/2. There is allegedly a modern replacement for the rare PP, but I do not have clear information.
Aftermarket flywheel is always an (expensive) option, as is redrilling whatever you have to take early Ford plate and disc.
Click to expand...

Bruce,

Can I use an 11" flywheel and pressure plate on my 8BA???
 
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