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post #1 of (permalink) Old 05-21-2007, 12:28 PM Thread Starter
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Clutch Shimmying

I have a fairly new Clutch installed in my CJ7 4.2L, I also had the Flywheel resurfaced on the last install. Pretty much everytime i've changed the clutch.

What would make the clutch shimmying after the jeep has gotten good and hot, say about after 20 mile of stop and go?

any help.
it's acting as if the flywheel has burnt spots..

83 cj7, 258 .030 over, HEi dist, Howell TBI.
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post #2 of (permalink) Old 05-22-2007, 04:20 PM
 
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Something is warping when it gets hot. I guess you'll have to either live with it or tear it apart. I'd be more inclined to think its the pressure plate part of the clutch than the flywheel. Mine's a bit chattery at times pulling away from a stop.
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post #3 of (permalink) Old 05-22-2007, 04:25 PM
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I had the same problem(s).
First time it ended up being loose bolts holding the bell housing on.
Second time it was the clutch. In talking with a jeep expert (who has seen the problems many times), about the only real solution was to use a factory clutch plate.

The problem will also be worse if you have larger tires and have not changed the gears. If you have stock gears and went to 32" tires, then it's about like trying to start off in second gear. When I put in 4.10 gears, then almost all of the shimmy went away.

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84 CJ7, SOA, 5.7LTBI, 4L60E, 35"x12.5, 4.10 gears, F/Det, R/ARB, Full Roll Cage,
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post #4 of (permalink) Old 05-22-2007, 04:54 PM Thread Starter
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thanks for the feedback guys.
I guess i need to look at maybe a heavyier duty clutch.
I am running 33x12.50's.
Running a stock clutch from a local parts store..

83 cj7, 258 .030 over, HEi dist, Howell TBI.
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post #5 of (permalink) Old 05-22-2007, 05:11 PM
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Quote:
I am running 33x12.50's.
...and stock gears?

Don't waste your money on another clutch yet...time for gears. You are going to have the same problem with any clutch you get.

Rule of Thumb (Thumb sure has a lot of rules)
32-33" tires = 4.10 gears
35" tires = 4.56 gears.

This will restore your engine RPM's to basically stock levels....if it's mostly off-road then you can't really go low enough.....

AKA DDawg16
84 CJ7, SOA, 5.7LTBI, 4L60E, 35"x12.5, 4.10 gears, F/Det, R/ARB, Full Roll Cage,
D44 Flat top in progress...
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post #6 of (permalink) Old 05-22-2007, 06:41 PM
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You got the standard oil leak at the back of the valve cover?

There are 10 kinds of people in the world.
Those who understand binary and those who don't.
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post #7 of (permalink) Old 05-22-2007, 06:49 PM
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Quote:
You got the standard oil leak at the back of the valve cover?
Very unlikely the problem. It would take one hell of a leak...and the position of the flywheel makes it very unlikely that even if oil could drip in that it would be able to fall on top of the flywheel....and if it did, you would have the smell of burning oil....and it would actually reduce the likelihood that you would get a shimmy....

Come on guys....read the posts fully.....33" tires....and I'm willing to bet that he has stock gears....

AKA DDawg16
84 CJ7, SOA, 5.7LTBI, 4L60E, 35"x12.5, 4.10 gears, F/Det, R/ARB, Full Roll Cage,
D44 Flat top in progress...
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post #8 of (permalink) Old 05-22-2007, 07:08 PM
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Talking

Clutch material gets a little softer, thus more "grabby" when it's hot.

Did your last clutch have the same problem - chatter?
Did you put on the bigger tires at the same time you did the clutch?
Did you re-gear at the same time you did the clutch?
Are you sure Gremlins didn't sneak in and change things during the night?

No? Then why would it suddenly cause chatter now?

Larger tires or wrong gearing just means you have to slip it a little longer. But it still should not "grab" or chatter.

It's usually an easy fix - about 80% of the time - a problem you introduced when installing it.

The engine/tranny has to be "neutralized.
Takes maybe 20 minutes.

Support the bellhousing with a jack. Raise it up a little until you see the mounts stop being compressed so hard.
Loosen the trans/bellhousing bolts - all of them, top and bottom - BUT only loosen them about 1/8" - 3/16" -- DO NOT BACK THEM OUT OR REMOVE THEM.
Notice the space between the trans and bellhousing. The top and bottom space should be the same IF it's in the "neutral" position. It won't be.

Now lift or lower the jack slightly - notice how when lifting you get the space at the top, none at the bottom, and visa-versa.
You want to take out the "sag."

Adjust the jack till that little space is EQUAL all around - including the sides. Now the trans is properly aligned. A little at a time, draw the bolts down criss cross pattern till tight, then torque to specs.

Done.

That slight mis-alignment times the length of the input shaft puts alot of strain on the shaft and pilot bushing/bearing, and causes the disk to not sit perfectly flat. One side of the disc touches harder than the other - chatter time.
It also helps the pilot last longer as well as the trans input bearing.

We are only talking thousandths, but it's important.

The small clearance between the bolt holes and the bolts can get the alignment way off if you aren't careful.

Even when attaching a T-Case to a Trans, or a bellhousing to the block the same caution should be taken to "neutralize" it.

It's the same idea as when you install a U-joint - and you give each ear a healthy whack with a hammer to "neutralize" it.

It's our fault - When we are installing it, after fighting to get the input through everything and get the bolts lined up, we are usually so excited we just run the bolts down tight, without ever thinking of alignment.

To do it right - after it's all installed and you've run the engine and operated the clutch a few times - THEN neutralize it.
It sure makes a big difference.

The first few hundred miles are critical to NOT let it chatter. Otherwise it will develop a wear pattern that it will make it always chatter.
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post #9 of (permalink) Old 05-22-2007, 07:16 PM
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Oil on the disk lining softens it - making it "grabby" = chatter. (Like oil or brake fluid on a brake lining.)

But oil from the top is unlikely to get on the disk- it would have to be a flood.

But - oil from the trans running up the input shaft can do it if the seal is bad. An overfull trans, a bad seal etc. But that should have been obvious when it was apart.

Check the linkages too.
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post #10 of (permalink) Old 05-22-2007, 07:30 PM Thread Starter
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Thanks Rich i'll try this. The clutch does have probably about 1,000 miles on it by now..
Do you still think that this will make a difference with the milage i have?

83 cj7, 258 .030 over, HEi dist, Howell TBI.
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