[Fot] Opinion Tyme Update

[Phil Gott]

Nick;
With an aluminum flywheel the problem could be with the steel friction surface. Are all the machine screws tight? Does the disc interfere with the aluminum around the periphery? Check for cracks. Take it off and use the magma flux penetrant crack test or even better have a shop do it on the steel surface. 
Even though the surface of the insert looks ok, it could have a glaze on it that grabs the disc. I’ve seen the on disc brakes.  The brakes will begin to judder  - alternating slip grip - yet the discs would look fine. Taking sandpaper to the discs will remove any material build up and the judder goes away. Best way to do this on the flywheel is to have a machine shop take a fine cut - or replace the insert.  If it is a very old Tilton like mine, the insert is available from AASCO Motorsports in Anaheim CA. 714 758 8500.
Hope this helps!
Phil

Sent from my iPhone

> On Apr 22, 2020, at 10:27 AM, Nick Black via Fot <fot at autox.team.net> wrote:
> 
> 
> Thanks  for all the ideas about this...
> 
> Mleccese - the car has a rubber seal on the crank and double seals on the trans...nice and dry in there, no oil leaks.
> 
> Tony - the car has a Tilton 7.25" setup with the "copper" colored full circumference disc (not individual "pucks") with a Tilton aluminum flywheel.
> 
> Marcel - the metal clutch line was not changed, but it wasn't kinked anywhere and I could blow thru it ok. The clutch feels as it always has just has this "instant" on/off that the driver cannot modulate.
> 
> David - the slave rod was in the center hole, but it worked the same when in the lower hole.
> The flywheel looks perfect and there is no measureable "bell" to it, no heat cracks or burrs.
> 
> Phil - the first "repair" was the disc, throwout sleeve. trans input shaft and diff change. The "full Monte" of changes have not been on track yet, but nothing that was replaced has been out of spec anywhere. The car has the steel throwout bearing flange and was pinned as it just doesn't seem rite to let steel on steel rotate. The pin was moved 90 degrees from where it was in case there was any unseeable wear from the fork on the sleeve.
> 
> Mike - Doubtful that anything "downstream" of the clutch is the problem. The trans was disassembled and the input shaft was changed after the first tyme. The driveshaft was inspected and rebalanced and the diff was changed to one that has been faultless for years, still had the problem.
> 
> The only other thing that has been changed is the clutch master diameter...went one size smaller as I thought that might give the driver a bit better chance to "modulate" the pedal. The interface twixt the throwout bearing and the throwout bearing flange has been relieved in case it may have gotten hung up somehow on the sleeve. The clearance twixt sleeve and throwout bearing flange is also within specs and moves easily by hand.
> 
> I'm about out of ideas here at this point and I have no confidence that any of these changes will affect the issue. It sure seems like I'm missing something here!
> 
> lack-o-slip here in NorCal
> Nick
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