F-Head Clutch Sizes

I'm reassembling my 3b's engine and just realized the clutch kit I got is an 8 1/2" diameter, and the one that was on it was 9 1/4". The different pressure plates use two seperate sets of holes in the flywheel. I didn't even think to measure before I ordered, and rock auto only offered one size for my application.

What application was the larger diameter for? Trucks and wagons?

I wish I would have looked into this deeper beforehand; I definitely would have opted for the larger diameter for how hard I abuse this thing.

I swear I've forgotten more about these things than I still know.

 

Hang on ...it doesn't get any better.

 

My buddy… "If only I knew then what I know now."

Me…. "If only I knew now what I knew then!"

 

I "used to could" is pretty much my life these days.

 

The Kaiser-era CJ's came with the larger clutch on the F134, including the last year ('64) of the 3B. Most of these also had a dual bolt pattern on the flywheel for either clutch size. I always preferred the 9 1/4", but have never seen the larger pressure plate in Howard's photo in post#2.
-Donny

 

I have no idea what this engine came out of originally. I can't even remember buying it. It went in after I made a hot-rod out of the last F-head and cooked that one.

Come to think of it, I swapped a V-6 in a '65 CJ5 back in the day around that time; maybe this is the 134 that came out of that.

I just searched Rockauto for a '65 CJ5, and there it is: an optional 9 1/4" clutch kit.

 

9-1/4" Auburn clutch became an option for all 134's in March of 1961.
This same clutch became the CJ standard just a couple years later.
This implies that all post 1962 Willys 134 flywheels are drilled to accept both clutch diameters.
Early flywheels can easily be machined to accept the 9-1/4" clutches.

 

Oldtime is correct. I have done extensive research on this as I am changing my drive train to the larger 9.25" clutch

 

There were also different size flywheels. My FC-150 that was passed down from my Grandfather had an issue where the starter wouldn't engage the flywheel. Once we dug back into it (long after Grandpa had passed) we found a smaller diameter flywheel that was a good 1/2-3/4 inch away from the starter. Grabbed a flywheel from an F-head that came out of a late 3B and voila! she cranked and fired.

 

I've run across a smaller diameter flywheel (by about 1") on an F134 that came out of a military forklift. Maybe this is what your grandfather's FC had?
-Donny

 

Only 3 versions of flywheels were ever used on 134 CJ's.
The Earliest was same as MB GPW #A-1443.
That one has the timing marks upon it.
The next version # 804314 came out with 1953 3B and no longer has any timing marks.
The latest version came out in 1961 and is identical to previous excepting it has 6 extra holes to accept the 9-1/4" clutch cover pattern.

 

For what its worth, I think I remember the starter on the military forklift extended behind the engine (top/center) instead of along side, similar to some marine applications. I'm not stating it was a Jeep flywheel, but that it was a smaller diameter flywheel on a Jeep-based engine. That engine also had close to 1/4" endplay on the crankshaft; the thrust (main) bearing was completely worn out, and the crank was way out of spec on the thrust surface.
-Donny

 

The 97 tooth compared to the 129 tooth ring gear might make the flywheel appear different diameters.

 

We surmised that it came from an industrial application of some sort. I've got a photo somewhere of the two.

 

I found the photo I have of the two. It does actually look like it could be the ring gear that's the difference. Been so long ago now, that I'm not completely sure what made us decide the entire flywheel was different, rather than just the ring gear.