Standard vs HD Clutch Disc

Mulletwagon

Mulletwagon

Well-known member
Does either disc perform any different ? The previous owner put in a new V-8 pressure plate and HD disc and that is when the clutch started chattering. Took it apart today. Will check the run out on housing and flywheel tomorrow but plan on putting in a standard disc. The HD disc clearly shows shinny spots and low areas that are not making contact with the flywheel and pressure plate. Also noted some minor contact between the stud end of the adjusting bolts on the release fingers and the edge of the flanges that retain the shock springs. Release finger heights were within about .005 inch. Watcha think ?
 
Saga continues. Checked the run out on the housing and flywheel and they dialed out to .004 and .003. The pilot and throw out bearings look new. The HD and standard Discs look very different. The HD has very large springs and many rivets hold the friction material to the backing. The friction band on the standard is also about .125 inch wider. Waiting on trans parts. Still cannot explain the chatter.
 
.004 is still within spec. Who makes the HD disc? The finger heights are supposed to be within .002. A finger adjustment solved my chattering clutch.
 
My suggestion:

What ever clutch disc you use, make sure it has retainers around each of the six springs on both sides

If you have the flywheel clutch surface machined, have the machinist restore the factory dimension between the clutch surface and the ridge the pressure plate bolts to; 1.123" is the factory dimension.

Make sure the flywheel has not been machined too many times such that the springs in the disc will contact the four flywheel mounting bolts. Before installing the clutch coat the heads of the bolts with chalk. Place the disk on the clutch surface of the flywheel and rotate it to see if any chalk transfers to the springs. It helps to grind a little metal off the heads of the four bolts.

Once the clutch is installed on the flywheel check, and adjust if necessary, the fingers of the pressure plate. They should be between 5\8" and 3\4", 11\16" being nominal. They all should be adjusted even.

Tom Endy
 
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The three release fingers terminate to adjustment studs secured by locknuts. Maybe not rocket science but would still welcome some insight from someone with experience adjusting a V8 pressure plate. The contact surfaces on the flywheel and pressure plate look like they were just machined. The flywheel has been cut down to accommodate the pressure plate and has been keyed (by a spot of spray paint) suggesting the pressure plate, flywheel, and crank were balanced as a unit.
 
I have the factory info and setup for the V8 clutches, I too once thought it was a black art, but if you follow the ford info its NOT.
let me know if you want a copy.
Lawrie
 
The rest of the story. Put in the standard duty clutch disc and now engagement is slicker than a crooked politician. Nothing else was done to the clutch system. The HD disc is used on truck applications but is also advertised for car application. Maybe the harder friction material and heavy springs are not completely compatible with a V-8 pressure plate in a car verses truck use. Don't know but sure like the results of the disc change. Anyone using a V-8 pressure plate with the truck disc ?
 
Now that is slick!! Interesting, I have a clutch that was chattering, I still haven't taken it apart to see if I can find the culprit.
 
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