8BA to 39 trans - clutch disk, pressure plate issues.

[Kevin Lee]

I have an 8BA that I'm trying to bolt up to a '39 toploader. As a bonus I happen to have a complete (non running) 59 Z to borrow some parts from to get the job done. Between the two motors I should have enough parts to make it work using nothing but a wrench, right? Well...I figured it would be as simple as swapping the early clutch and pressure plate to get the big spline pattern for the early transmission. It didn't take long to figure out the difference in the bolt pattern. I tried to swap the clutch disk only but the early disk measures a full 10 inches compared to the late disk at 9 1/2 so it won't fit without interference.

Is there a 9 1/2 inch disk with the big spline pattern available? Am I going to have to swap flywheels and will that cause issues with the starter? Is there a fix that is so completely obvious that I should be slapping my forehead right now?

[Bruce Lancaster]

"different bolt pattern"--first, is the bolt pattern on your wheel 3 pairs of holes with wide gaps between pairs or are the holes evenly spaced?? If evenly spaced, you have a Merc wheel for Borg&Beck clutch, and need a Merc throwout bearing. A '49-50 Mrc disc should then tie all together.
If the bolt holes are 3 pairs, your wheeel is Ford and wants a Long style pressure plate. Since it's a late model, it would be either 10" passenger or 11" truck. Early Ford wheels alsa came in 9".
Another thing: You MIGHT be able to swap the complete flywheel over from the 59. There is a small difference longitudinally in starter ring gear placement, compensated for in the location of the starter mount. I have never mixed these particular parts (dumb luck there, since I didn't useta know the difference), but understand that sometimes starter drive travel accepts the swap and sometimes it doesn't. Test it out by first just operating the Bendix gear by hand, then if it looks OK hookitup to a battery and see if it will crank properly.
The actual starters are the same except for1951--? automatic trans ones.

[Kevin Lee]

Three sets of two holes - not a Borg&Beck. The LATE clutch disk itself measures 9 1/2 inches. Would that be a 10 inch or 9 inch then? The EARLY one is the bigger one at 10 inches exactly.

Maybe I can just swap the flywheels - shouldn't be too hard? But I'm scratching my head as to how I could do anything to the starter by hand to check the interface with everything bolted up.

[Bruce Lancaster]

Hmmm...I think but am not sure that old Ford 10" discs are about an actual 10"--not that I check up on such things, but I have measured the swept part of flywheels to determine what I had, and I must have gotten even measurements since I don't remember having been confused, as I certainly would have been with 9 1/2".
I believe that 9 1/2 is probably a modern replacement part. What diameter is the actual plate in the pressure plate you've got? Is there a wear pattern on the flywheel outside that made by the 9 1/2? On the starter, it's been a long time since I've actually worked on a latemodel bell housing, but the starter drive does go behind the flywheel--can you get at it with bellhousing and wheel on/pressure plate and trans off?
Or just boltiitalltogether and apply a battery and see if it engages and cranks--you could do that pretty easily even with engine just sitting on the floor.
I don't have any literature here to check, but I believe 10 and 11 are the only normal sizes for late flathead discs.

[Kevin Lee]

Well, clutch fits the plate and there was no strange wear on the wheel that I remember. In the meantime I found this at the Ford techno site under "Retro 4 speed to 8BA". Not what I'm doing but at least it confirms the measurement.
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5: If you are going to make anykind of power be sure to locate and install the larger clutch/pressure plate hook up from a taxi or police car...stock was 9 1/2 tax/police 10 inch....pressure plate mearly has to fit flywheel and clutch must fit pressure plate and inputshaft of trans...any half decent parts place can match you up.
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Looks like I need a "half decent parts place" http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif I'll do some measuring around the bellhousing/flywheel area and just swap the flywheels if it looks workable. Sure would be a lot easier if I could just find a 9 1/2" clutch with the large spline pattern.

[Bruce Lancaster]

Maybe 1949-50 Merc?

[Kevin Lee]

My brain hurts.

[flatoz]

Grimlock ,

check out places like reds headers macs etc, they should have a clutch plate for you they were available as I have a couple ( no good for you as rusted to the shit) but they are there.

unless you just change the complete flywheel/clutch/pressure plate set up but I guess thats $$ you dont want to spend if you dont have to.

Try putting an ad in fordbarn, might turn up a usable clutch disc for a few $.

good luck, glad to see another flathead coming to life!

[Bruce Lancaster]

OK, I've done some research in this strange late model stuff. The '49 up Fords did use the 9 1/2 as standard, something new to me. Merc won't work, as it retained the earlier 10" setup. This quite likely means that there isn't a standard disc around with 9 1/2" diameter and early splines. So...
1. Call up the high performance hotrod oriented clutch manufacturers that make stuff for camaros and mustangs. According to article I have read, they routinely rivet together odd hub/disc combos for rodders.
2. Use an early Ford 9" disc, standard 1928-about '42, also 9N type tractors--should be available through both modern and restoration channels. This should have plenty of capacity for a tiny car like yours--yours is probably half the weight of a '41 Ford, and if you were shopping for parts I would recommend a 9" setup for its lighter weight anyhow.
3.put on the whole assembly from the early engine, put in the starter, and jumper cable it to a battery--if it engages smoothly and cranks, go with it.
4. Excellent suggestion above--call Red's. He also has lots of used parts, and might even turn up a cutdown '49 wheel with redrill for 9" clutch for you.
5.scrapitandbuyahonda.
I've just sent off more parts for the earlification kit, by the way. Bruce

[Kevin Lee]

Alright. Good news and bad news.

Bad news is the flywheel swap was a complete flop. Who would have thought that 3/16" or so would be such a big deal? The idler gear cover as well as the block casting itself were not happy. This wasn't the wierd dished flywheel by the way. Just the big flat piece that apparently has dimentions just close enough to make you think it might work...it doesn't

GOOD NEWS - Called Casper Brake and Clutch this morning. This is the outfit in Downtown KC that relined my brake shoes for eleven dollars a wheel. I'm really starting to love that area of town. Small shops that seem to love the old stuff (even if it is a "late model" flathead) when they see or hear of it. I was told that their clutch guy was recovering from surgery. How is that good news? He'll be back next week and I was assured that he would be able to tell me off the top of his head what aplication used a 9 1/2" disk and "large spline" (1 3/8") in the middle. If there's not one available they'll most likely be able to swap the centers and add new friction material. I'll compare this to the cost and availability issues of getting a 9" pressure plate and disk and do what makes more sense. So starter should be a non-issue if I can keep this wheel.

I couldn't make sense of your fifth option. Those last few letters have me scratching my head. I'll be eagerly watching the mailbox.

[DetroitDraggin]

The most economical way to circumvent this issue is to do exactly what you figured out. Have the clutch disc center changed at a reputable clutch shop. End of problem. Cheap fix and perfect. No changes to anything else. Good luck!

Bill
Brothers Custom Auto LLC
Clawson, MI

[TERPU]

I used a 9" early clutch 'cause that's what the old timers told me to do. It works fine with all the 8BA stuff.


Thanks,
Tim

[Fortyfordguy]

You found out the common problem using the flywheels between the 1942-48 motors (which includes all 59 series engines) and the late style motors (1949-53).

The passenger car clutches from 42-48 were all 10" diameter except the large trucks which had the big old 11" clutch....not exactly user friendly on your leg. You can tell a 42-48 flywheel by measuring the thickness of the flywheel in this manner: from the rear edge of the ring gear to the friction (clutch side) edge. These will measure about 3/4"

The Ford car and pickup truck flywheels from 49-53 were thinner in this area. You would measure these at about 5/8" thick. This thickness is the same for the 49-53 Merc flywheels.

The 42-48 flywheels and the 49-53 flywheels do not interchange. Aside from the following clutch issues, the flywheels position the ring gear differently, causing starter engagement problems.

Remember this about the clutches though: The Ford cars clutches were 9-1/2" diameter...UNLESS it had the police or other special order clutch which was 10". In either case, the input shaft clutch spline was ten spline with 1" OD. The pressure plates were a matching 9-1/2" (or 10" on special order jobs) with the three pairs of bolt holes.

The Merc clutch for 49-51 was the Borg & Beck type with 10" diameter. The pressure plate bolt holes were equi-distant from one another. Because of the bolt pattern, you cannot simply bolt a 1942-48 ten inch pressure plate to the 49-51 Merc flywheel. The input shaft spline of the trans was the ten spline of 1-3/8" OD....just like all the early V8 clutches from 1932-48. For those wondering, the 52-53 Merc clutches went with the smaller 1" OD ten spline hub.

Now, to repeat your earlier conclusion about a simple swapping of flywheels. Cannot be done between the 1942-48 variety and the 49-53 variety, whether Ford or Merc. However, you can use any late style (49-53) flywheel and have it redrilled for the proper pressure plate bolt holes that you want. Another solution, as someone pointed out, it to keep the Ford late style flywheel that was set up for 9-1/2" dia clutch, and have a new clutch mfr'd of the same diameter, but with the hub/spline needed for your trans. THIS however is the next conumdrum. If you are using any early Ford trans with the 1-3/8" input shaft, the matching throw-out bearing will not fit up to the fingers of the 9-1/2" pressure plate properly, causing a new set of problems. So, in my humble opinion, it is best to have a 49-53 flywheel redrilled to match the 10" dia pressure plate that would have come with the earlier style trannies.

Now, last notes on the flywheel modifications. Check your machine shop.....not all have the capacity to re-drill the flywheels. Make sure they get the correct bolt pattern by giving them a new or used pressure plate to position the holes correctly. They need to be drilled and tapped correctly for the special shoulder bolts used to hold the pressure plate. And finally, if possible, have your redrilled flywheel surfaced. Replace the ring gear now if the teeth are chewed up. Give the shop your new or rebuilt pressure plate and have them balance the assembly. It should come back marked with paint or something to let you remount the plate when you are ready to install the clutch disc.

Hope this makes sense to everyone............. Mac VP

www.flatheadv8.com

[54BOMB]

5 years guys?

[392_hemi]

That's funny. Sure hope he's got it sorted out by now!

[MrModelT]

I too am working on mating a '53 8BA to a '39 "78-7006" transmission and am now very confused. I was always under the impression that setting up a late model Flatie and an early box was never this much work. Yes, given that over 20 some odd years of production there are bound to be part differences, but I always remember there being WAY more compatibility between early boxes and later engines. Am I wrong here? I always thought you could bolt a older 9" clutch with 1.3/8" splines to the 59A and 8BA flywheels and that the trannies would interchange with just about any year engine like TERPU states. I personally would like to understand this better for my own knowlage before I start my project.

[Rocky]

5 years guys?
Yeah, he got it.....here's proof. The clutch worked ok but needed a little adjustment after the first 'test beat'....

[GARY?]

Now I can sleep a little easier.;)

[Southfork]

Yea, that 5-yr-old thread threw me for a minute. I wondered if Kevin decided to go by the "Grimlock" handle again. Now I also want to know whether that uber-rare 59Z flatty that kevin referred to ever got put together and run.

[Bruce Lancaster]

For the record...stock combos that will actuall fit to early trans with no hassle:
Late truck with 11"...all fits, but stupid choice of heavy clutch for most rods
'49-50 and SOME 1951 Merc, B&B clutch that used early spline and early throwout.
10" clutches existed, but only on HD applications. I've never seen one.
Did pickups ever come with 10" clutch?? I don't know this late model stuff. If they did, that would be a sensible bolt together, and a 10" passenger wheel (if you can find one) would allow use of '42-48 pressure plate and disc.
Redrilling for 9 or 10 would be best solution as it would allow future repair with normal parts...I would think having multiple patterns drilled would likel;y be nearly as cheap as single, too.

[19Fordy]

When I installed a 1953 Merc V-8 in my 40 Ford (30 years ago) with the stock 40 transmission I used (as best I can remember) the 49-51 Merc steel bellhousing and starter plate , the stock Merc pressure plate and a 46-48 Ford truck clutch plate. I recall that the truck clutch was 10 in. It's been so long ago so please check and see if that make's sense.

[Bruce Lancaster]

The '49-early 1951 Mercs with basically early Ford trans have a B&B PP that fits the early Ford throwout. The '51-53 Mercs also used a B&B I think, but had the late Ford trans with small input and a smaller throwout that won't fit the early stuff...you probably swapped to earlier