Clutch chatter

[Dick Deegan]

I have had some degree or another of clutch chatter most of the years that I have owned this car. I am currently trying to eliminate it. Here's what I have done.
- had the engine out last fall and checked crank to flywheel housing runout and shimmed to get it close to spec (0.006" I believe).
- checked flywheel runout and seemed OK (don't remember the number)
- replaced throwout bearing
- pressure plate and clutch disc replaced about 4 years ago
- recently checked pressure plate finger adjustment and got them as close as I can with the engine in the car
- adjusted clutch free play to about 1 1/2 " etc. etc. etc.

Here's some other facts:
- I have FAM's. I have adjusted the front motor mount so that the nut is only tight enough to get the cotter in. I have adjusted the FAM's so that they are just slightly tight and then I tried them very tight - no difference except for engine vibration with the very tight adjustment
- tranny mount is there
- While adjusting the clutch free play there is a LOT of slop between the hole in the clutch pedal and the trunion nut (1/8" approx.)
- a couple of years ago I went back to the original motor mounts - chatter still there.

Where do I go from here?

Frustrated Dick

[BRENT in 10-uh-C]

Generally I find that clutch chatter is caused by a worn input shaft or pilot bearing. If those are out of centerline buy just a few thousandths or more, the clutch plates creates a vibration until it can seek center.

You mentioned you have shimmed the flywheel housing (which can also cause this if not properly aligned) but I also find many cast iron flywheel housings are warped and need to be machined flat again.

[Purdy Swoft]

Besides the other suggestions, You might try more retard at the spark lever when taking off to cushion out the chatter.

[columbiA]

If the trunion is badly warn on underside,just turn it around & you will have a new surface.Looseness above trunion doesnt matter grease trunion when putting together & oil it when serviceing the car & pedal will be easier to push & prevent wear.A clutch release arm about 3/4" shorter willmake it feel like a 35-46 V8 clutch without the cost of converting to the V8 clutch as it still uses the 9" disc.The std A PP should always use the later style spring dampened disc for smoother engagement.

[James Rogers]

You will find the V8 pressure plate will provide a more positive clamp when engaging. The clamping force of a Model A plate is 1800PSI where a V8 is 2400PSI making the engagment more positive and most times eliminating chatter if the plate is the problem.

[Patrick L.]

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The causes of chatter have been well covered. I have a question about the finger height adjustment. When setting them in the car, I use a long feeler strip in the .0015-.002" range. I mark the finger[s] that touch the bearing and set the others with the feeler strip for an equal drag on all. It takes a couple laps around the pressure plate to get them even.
When you installed the clutch, did you replace the release bearing and check the shaft as Brent mentioned ?
I think some folks have mentioned having chatter trouble with Floater mounts, but, I can't speak to that.

[columbiA]

The V8 PP withnthe centrifugal weights is of no nhelp in a model A as the weights only come into effect at higher RPM s,which the low rev A engine does not have,therefor of no advantage in an A,regardless what anybody says. Thats my story,and I am sticking to it!

[Dick Deegan]

I did in fact check the pilot bearing, which seemed to be OK, but I didn't actually mount it on the input shaft to see if there was any play. I did change the throw out bearing and put in a top quality one (so the supplier said). Please see my post below.

Dick

[Dick Deegan]

First of all I would like to thank everyone who responded to my question on clutch chatter. Before I initiated the thread I did do a search, but couldn't find anything that corresponded to my situation.

I did check the PP fingers again and made some minor adjustments. Thank you Cape Codder for the heads up on the Permatex Penetrating Grade Threadlocker Green. I contacted NAPA and they had some for me this morning.

Thanks for the idea on spark retard Purdy. I tried it and it seems to work, greatly reducing the chatter.

I did do something that had an immediate impact. I sprayed the clutch plate liberally with brake cleaner while the engine was at a slow idle. The excess ran out of the bottom of the bell housing. While I was spraying my wife moved the clutch in and out. I took the car for a spin immediately after and - no chatter. That would indicate to me that I am getting oil on the clutch plate - perhaps from the transmission??

Any further thoughts?

Dick

[1931 flamingo]

I would think if you were getting oil on the disc/flywheel you would get slippage and not chatter.?
Paul in CT

[Mitch//pa]

look in the inspection cover if its getting on the clutch it should also be slung all inside the clutch housing

[James Rogers]

Originally Posted by 1931 flamingo

I would think if you were getting oil on the disc/flywheel you would get slippage and not chatter.?
Paul in CT

The clutch is liike the brake linings. If you get oil on either, they will grab, not slip.

[columbiA]

On my #9 post on 07-05-13,I made a boo-boo by stateing that the release arm should be shorter.I didnt proof read it but Tom wesenburg spotted it.thanks Tom!It should have said LENGTHEN it by 3/4".Hope no one shortened theirs already!

[James Rogers]

Originally Posted by columbiA

On my #9 post on 07-05-13,I made a boo-boo by stateing that the release arm should be shorter.I didnt proof read it but Tom wesenburg spotted it.thanks Tom!It should have said LENGTHEN it by 3/4".Hope no one shortened theirs already!

Post #4