Terrible judder from new ACT clutch but only when engine has warm-up
 

OK, I took my 1994 Miata out today to fill her up. The ACT sport street clutch which was installed by a reputable Seattle area shop less than 500 miles ago was operating as smooth as could be.....no problems. On the way back I reached 60mph on a quiet road, arrived home, hesitated before pulling up the gentle slope of my driveway and the horrible judder was back. So i reversed back down onto the street and it juddered, I tried to gently "feather" the clutch as i took off down the street and again a bad judder, tried increasing the revs….bad judder! So i put her back in the garage and slammed the garage door. What the **** is causing it?
If I wait several hours for the engine to cool down it will be fine again until it warms back up. Absolutely no sign of slippage. The origin shop invoice says that they resurfaced the original flywheel before installing the ACT. I took it easy for the first 500 miles although since the shop is 160 miles from my home I kept the speed below 65 and tried to vary it as much as possible on a freeway on the trip home. Has anyone got an answer? Surely if it was fluid leaking on the pressure plate or high spots on it the problem would be immediately apparent while the engine was still cold.

Have you any idea given the symptoms what might be causing the problem. I retire in less than 8 weeks now and won’t have a lot of spare cash to throw at the car it it gets any worse. This was supposed to be my “fun” car in retirement.

Since no one answered me on this forum I might as well tell you how the problem was solved. Apparently the "reputable" original clutch installer did NOT resurface the flywheel as he claimed according to my new installer. It was quite evident when inspected, I switched out the new ACT clutch for a new Mazdaspeed clutch assembly and had the flywheel machined correctly and all is well with the world. If anyone want a nearly new ACT road sport clutch assembly really cheap I have one for you.