I've got a LS7 clutch and Tick/Tilton adjustable master that are both about 10 years old. I also have the Fidanza flywheel and the friction plate has been replaced once in that time frame. When my motor was rebuilt a few months ago, the shop looked at the clutch and said it still looked in great shape so we re-used it. I wanted to buy a replacement flywheel insert but they were back ordered at least a few weeks and I couldn't get them anywhere. Based upon my conversation with Fidanza, the flywheel insert only needed minor cleanup and we also put in a new GM (not Luk although I think they are the same) slave cylinder. Clutch has seemed completely normal (i.e., the same way it felt prior to pulling the motor) since I got the car back maybe 6-8 weeks ago. I previously used Castrol SRF for both brake and clutch fluid, and that's what I provided the shop for any necessary brake/clutch bleeding.

Driving back from a company event yesterday afternoon, on the interstate in heavy stop and go traffic, I noticed that the clutch pedal engagement point was moving around. Sometimes it was engaging right off the floor, and over time it would gradually fluctuate between it's normal position near the top and the bottom. Once I was back in city traffic, the clutch seemed back to normal. I drove it to the store later last night and it again felt normal. I haven't had a reason to drive it since last night, and upon checking the clutch fluid today it is clear and full.

We did expect to need a replacement clutch sooner rather than later because of the now larger displacement engine. I've got another clutch on my to-buy list, but life keeps interrupting. It's strange that it's taken so long to show up after I got the car back, I don't think I can place this issue on the shop as a result, I figured it was hydraulic, but the fluid is full...?

Edit: I drove the car again for the first time tonight, pedal still feels normal.

 

is your hydraulic line near header/exhaust?

if so sounds like your fluid is getting hot

 

Bingo! That appears to be the case

The rubber exterior of the clutch hydraulic line was resting against the #7 primary.The area of the line where it was touching has a a rough spot, unsure whether the line needs to be replaced, or add some sort of heat shield, or just tie it away as-is. I've been looking for some sort of heat shield that I can install without removing the line, but anything with Velcro that you have to trim to length seems to fall apart.

 

I use this split loom heat wrap. Got it at Summit. Tie it back away also

https://vibrantperformance.com/catal...47b1bdcb442a46

 

Do you still have your clutch pedal return spring on? What you’re describing is what I have right now and have the same MC. I had to pull mine out since it pretty hard to press the pedal and actually broke it off. I think it even says on tick’s instructions that you have to remove it.

 

Not sure, it currently behaves as it had for years, and it's not hard to press the pedal. If someone has a photo of how to check the return spring under the panel, I'll check this weekend.