Pressure Plate Swap...

[athawk11]

Gentlemen,

Take a look at this flywheel...



It appears to me that it has been drilled and tapped to accept the larger pressure plate found on a CJ5, and the smaller pressure plate found on a CJ3A.� Can someone confirm this?� �

I have the larger pressure plate and clutch installed now.

Tim�

[garage gnome]

I didn't even know that the CJ5s had larger clutches. Does anyone know when they changed the size?

[Ryan_M]

Very interesting. I wonder if that was some sort of aftermarket "one-size-fits-all" flywheel? It definitely looks like you could use your choice of 3A or CJ5 clutches.

[oldtime]

That's an original flywheel.
See: http://cj3b.info/Tech/ServiceBulletins2.html

[athawk11]

Very good info Oldtime.  The reason I ask...

I may be having some 'interference' issues.  They make reference to this at the bottom of the listed bulletin.

Tim

[Tumbleweed]

Tim,

My 3A does not have the 6 outer bolt holes as yours indicates. My flywheel only has the 6 inner bolts holes and it is the original flywheel. I can see where a larger pressure plate would cause some fit issues since the call out is for 8 1/2". If you look at the pressure plate with the larger diameter this may rub a little on the bell hsg.

I have not assembled my clutch yet but I did get my flywheel installed a couple of weeks ago. It would be interesting to see the dimensional changes from 8 1/2" to your larger pressure plate. My parts guy in Texas asked me if I wanted a larger clutch and pressure plate but I told him I didi not know if this was an option. I'm taking my old parts to him and I will see what he has in mind. I will probably just go with the standard clutch though.

Regards,

George

[athawk11]

Hi George,

Based on the bulletin posted by Oldtime, it looks like there was a change to the flywheel in later CJ production that would allow the 8.5� clutch with matching plate, or the 9.25� clutch with matching plate.� The latter offering improved torque and pressure.� This is likely why my flywheel is drilled for both options.� My flywheel and bell housing are from a CJ3B or CJ5.�

Speculation:� The PO may have made this upgrade when his original 6 volt starter crapped out, or he was ready to do a 12volt conversion.� 12volt starters for CJ5s were probably readily available at the time. Only way to get this type of starter would be to swap out the whole back side of the engine.� Again, just one possible answer.

I�m going to have to take this thing apart�again.� I�ll do some side by side comparisons to see what�s up.� Hopefully there will be something interesting to share�other than � That Tim is a real dumb-*rear end.�

Tim� �

[oldtime]

On my F-heads that's the only flywheel that I ever use.
It was drilled that way original from the factory.
In 1961 it gave one the option to bolt up the larger optional clutch.
The 9-1/4" clutch later became standard in 1965.

I never thought about it before but I suppose there could feasibly be some bellhousing clearance issues if using a larger clutch with the pre 1953 bellhousings.
For post 1953 bellhousings there are 2 versions.
Both post 1953 bellhousings work perfectly well with the 9-1/4" Auburn clutches.
The 1953 bellhousing change was done to improve starter drive engagement.
The post 1953 bellhousings effects ones choice of starter and also mandates the 126 tooth ring gear.

For Willys the change over to the 12 volt standard occurs in 1958.
The 6 volt starters for use with 126 tooth ring gear remained as an option through 1962.

There is no disadvantage to the late type flywheel.
If desired it will accept the pre 1953 ring gear (97 tooth).
One also needs to be aware that the larger clutch size will effect your choice for clutch control linkage.

[Mark W.]

OK guys I know all about this as I am in the middle of upgrading to a 9.25" Clutch.

You will need:

The Flywheel Drilled as shown above with the 6 evenly spaced pressure plate bolt mounting holes. This flywheel requires the two tapered cones be in your crankshaft (so if you do not have this already it will require you to drop your crank and all the fun stuff that involves) This is a 129 Tooth flywheel

The Bell Housing has to be the enclosed nose style that has all the mounting bolt holes in about a 2" long boss. This is to allow clearance for the larger pressure plate.

The matching Rear Plate that goes with the above listed Bell Housing. Its the only one the starter hole will match up to.

A 9.25" Disc and Pressure Plate

The Starter must be the enclosed nose style designed to be used with a 129 tooth Ring gear. (the big plus here is that it also allows a '64-'83 Toyota 4.2L, Nippondenso PN 02800-2362/4 starter to be used at a cost of $60.00 instead of what a rebuilt Willys Starter can run.)

The Clutch Cross Shaft should also be the one designed to work with the 9.25" clutch (walcks carries them)

All other parts are the same as the 8.5" clutch.

[athawk11]

Thanks for the feedback Mark.� To catch you up, I have what you're upgrading to.� I'm at rolling chassis stage and have a strange rattling sound coming from the bell housing.� It comes, then goes at about 1000 RPMs.� Almost like an interference issue, or something has come lose.� It makes this noise whether I'm in gear or in neutral.� It does it with the clutch engaged or disengaged.

I must say, I don't think you need the different style cross shaft. I have the standard style for the L134.� Besides this odd rumbling sound, the clutch system performs as it should.

Tim

[Mark W.]

DUDE I love the paint on the Bell Housing. Mine is currently New Ford Gray which we chose because it will pop against the Orange Red that my inner fenders and firewall will be. And contrast nicely with the Semi Gloss Black I am using for various parts in the engine compartment.

I'm hoping to be very close to your progress by late Spring. If I run out of funds for the drive train I'm going to switch to body work.

[Carls_jeep]

I don't know why you would need a bigger stronger clutch for these Jeeps. I still use the original size clutch and have put my Jeep through some very hard stress and have never had the clutch slip. One thing I don't do is slip the clutch when trying to do hard things. I engage the clutch and remove my foot from the pedal and let the engine, clutch and drive line do the work. I don't think the L head or F head engine has enough power to slip the stock clutch.

[athawk11]

Thanks Mark.  I decided to have a little fun with this one.  I am following your build at the 2A. 

I agree with you Carl.� This set up isn't really necessary, but as many of us have discovered, POs made some odd choices. :-/

Tim

[1955CJ-5]

Almost like an interference issue, or something has come lose.

Bretto had a noise also...I think it was one of the springs that provide tension on the pressure plate "fingers" that had broken or come loose...I'll see if I can find the thread...


It was over at the 2a forum..

http://www.thecj2apage.com/forums/clutch-noise_topic33237.html

[Mark W.]

Not to start an argument but if the larger clutch was not advantageous why would Willys and then Kaiser both offer it as an option?

I plan on doing some towing with my Jeep and just as I would upgrade my brakes to stop I am upgrading my clutch to get going. While there are lots of ways to use a Willys Jeep that the 8.5" clutch is perfectly adequate there are other it is not. Try pulling a stump with your 8.5" clutch and see if you couldn't use a bigger clutch, Pulling your buddies Toyota or Ford out of the ditch, mud hole or snow bank. Heck try pulling a 2 bottom plow 8" deep in Sandy Loam soil all day long and see if a larger clutch wouldn't reduce the wear and tear.

If I had a running driving survivor Willys I would most likely never go to the cost and effort to upgrade the clutch. But almost every piece I am buying to do this needed to be replaced to get my Jeep back on the road and to the condition I want it.

SO I AM.