Asking for a favor
 

A little odd request. I would like the members here to help me comprise a list of all the possible causes of clutch chatter. I have had a high compression head on my bench that I was planning to install, when I had the engine out to chase down the chatter issue. Recently my daughter planned for the car to be in the wedding, and I was planning to drive the car to the venue. With all the hills around here I went ahead and put the 6-1 Snyder head on the car to make the drive to the venue a better trip. Wow, I am so pleased with the performance gain. But the chatter is alive and terribly annoying. So after the wedding I plan to go all out and get the problem solved by pulling the engine out and starting with checking the flywheel housing alignment. Please help with your experiences and I will try everything.

Looking for cause and resolution. Thank you kindly guys and gals.

P.S. the car has a '39 tranny Clings modification with a lightened A flywheel and Long style clutch. Clutch and flywheel were professionally balanced by a very reputable shop.

Re: Asking for a favor
 

My experience is the biggest single cause of Clutch Chatter is from a worn input shaft or pilot bearing, -or both. Even the front case bearing can be worn and can cause a light chatter but it is typically found on the opposite end of the shaft. Typically speaking the flywheel housing alignment is not the sole cause of chatter. Again, if the clutch disc is not aligned to the crankshaft centerline, the disc spins much like an orbital DA sander when first engaged until centrifugal force self aligns the disc to the crankshaft centerline.


In your circumstance, it is always possible the rebuilder that did the modification on the flywheel missed the centerline when the bolts were drilled for the new pressure plate bolts. The pressure plate can be balanced to the flywheel however if the pressure plate is not running concentric to the flywheel, it will cause a problem.

Re: Asking for a favor
 

my clutch chattered because a former helper of my grandpa thought he could fix a stuck clutch by playing with the adjusters through the hole with no plan on how to do that. The fix for that was to properly adjust the fingers when the motor came out for a bore. I think there are some threads about methods of adjustment in car.


my chatter was when releasing the clutch on take off a wop wop wop wop and then gone once fully engaged and not noticed when shifting between gears or cruising.


here is a video I used as a clutch adjustment guide. the video suggests 3/4in it worked for me. I have seen differing opinion from 5/8 to 7/8 https://www.youtube.com/watch?v=3CHUZTgyf0g

Re: Asking for a favor
 

Check your private messages.
Marshall

Re: Asking for a favor
 

My clutch chattered bad, like a paint shaker when I first bought my car. Now it's smooth as an automatic after I installed a new clutch disc from a swap meet, good used pressure plate from a swap meet, lightly sanded the flywheel using my electric 1/4 sheet palm sander, and dialed in the flywheel cover.

Re: Asking for a favor
 

Many times a person will notice chatter after installing floating rear motor mounts. If the motor mounts are too tight or too loose it will cause chatter . Sometimes it can be trial and error to find the happy medium for tightening the motor mounts , front and rear . An out of balance flywheel can be a cause of chatter .

Re: Asking for a favor
 

To add to what Purdy said, it was suggested to me to ensure the FAM rear transmission mount is installed correctly. After checking mine I found the rubber insert was missing.

Thanks to those that are willing share their experiences with all so we can learn.

Re: Asking for a favor
 

I removed the Float 0 Motors and went back to stock, this helped, but installing a diaphragm clutch is what totally cured it.

Re: Asking for a favor
 

Clutch friction disks "in the day" were solid - no springs. Most today available have springs between the center hub and the friction disk. We've had discussion here about the clutching differences between a "sprung disk" and an "un-sprung" disk.

I might opine that a solid disk are more prone to chattering. But others have held the opinion the sprung are more prone.

IIRC, you can still buy both.

Joe K

Re: Asking for a favor
 

When I installed the floating motor mount on the coupe , back in 79 . I figured that I didn't need the rear transmission mount and rubber insert . It was smooth it first but after a short time it developed a shimmy when taking off . I drove the coupe for years with the shimmy . One day it dawned on me that leaving off the rear transmission mount could be the problem . Using the donut rear motor mount and the distance between the rear of the engine and the center crossmember will give more up and down movement of the engine . The rear of the transmission needs the rear transmission mount to stabilize the engine and transmission so as to avoid chatter . The rubber insert fits between the front lower edge of the center cross member and the metal rear transmission mount that comes with the kit. The rubber insert raises and cushions the transmission mount for good stabilization and removal of chatter .

Re: Asking for a favor
 

Sent U a message!

Re: Asking for a favor
 

Thanks people for the input! Keep it coming if you can. One interesting thought brought to mind that could be productive is to add a rear transmission mount, similar to the float a motor rear mount. As things are with the 39 tranny Clings kit there is no rear tranny support. In the V8 setup that area is well supported. Comments?

Re: Asking for a favor
 

Bump for comment?

Re: Asking for a favor
 

Often a sagging frame at the rear motor mounts causes chatter even if floating mounts are not used . Over the years a lot of people have left off the rear transmission mount . These rear mounts often show up at swap meets . The rear transmission mount ALONE will usually remove chatter . A sagging frame will cause the torque tube to drag on the service brake cross shaft . A rear transmission mount from a float A motor kit alone will remove the drag on the brake shaft , I've done it .

Re: Asking for a favor
 

The chatter on my newly, professionally restored engine seemed innocuous to begin with but got progressively worse. I chased all kinds of theories and opinions, mainly dealing with my float a motor mounts. Around 5,000 miles I pulled the engine and discovered that the builder or machinist had "balanced" my clutch by adding weld to the pressure plate in several locations. Opposite each weld on the mating surface was a very clear "hot spot" where the disc had been chattering. Pressure plates must be drilled, not welded as welding distorts the metal and causes the surface to have high and low spots. New pressure plate and all has been well!

Re: Asking for a favor
 

Lightened flywheel + V8 clutch with springs + repro springs in front engine support.

Re: Asking for a favor
 

Bob, are you saying that's a formula for clutch chatter?

When I finished my truck, it was 100% A correct. It chattered.

Re: Asking for a favor
 

I would love to know what information was communicated In the various PM's announced in this thread! Maybe the real secret to fixing chatter?

Re: Asking for a favor
 

I wondered about that too:)

Re: Asking for a favor
 

Yes it is unfortunate, a lot of us are here to learn and PMs don't do anything towards that.