Clutch Failing

[Valkyrie14]

Stock clutch, squeaky tick master cylinder, tick external reservoir, 100,000 miles. Not saying anything negative about tick, my master cylinder is squeaky which may be related to the issue I describe here, or maybe not.

Going 65 on highway and kids pass me wanting me show them something. I downshift into 4th and gas it. Pedal mash revs up to 80, starts to redline, I shift into 5th and mash continues. I let off everything and the smell of burnt fluid is strong.

I am used to pedal mash when launching. But this was new.

I have been wanting a dual disc clutch for awhile, so it is easy for me to decide this summer is finally the time. BUT, is there something else going on here? I will be super pissed if I put in a $2,000 clutch kit and go out to let we rip and have pedal mash.

[gtstorey]

Not sure what "pedal mash" is but typical a failed master cylinder would fail by not applying pressure to the fluid, not holding pressure but I have seen old rusty master cylinders hold pressure the plunger was stuck. I doubt that is your problem though.

By stock clutch do you mean original with 100k miles? I don't see much reason the expect anything other than a worn clutch if that is the case. If 5000 miles maybe need to look further. But even then you are well beyond stock power.

[Valkyrie14]

Peda mash means that the clutch pedal pulls itself to the floor and the rpm’s shoot up to 7000-7500, without the desired acceleration.
Yes, 100,000 on original clutch. The clutch has always been stiff and has always done the pedal mash when I try to launch. My launch technique is only letting rpm’s up to 3,000 before disengaging the clutch. So I followed some threads on here about that and switched to an external reservoir. When that didn’t work I went to a tick master cylinder, that also has an insulated line. That didn’t work, plus it squeaks super loud.
For normal driving the clutch works, it is just stiff and squeaky. No slipping that I notice. But what is the point of have a supercharged LS3 if every time you want to get on it the clutch mashes to the floor.

[gtstorey]

I would guess your clutch is on borrowed time at 100k and increased power, but I don't have a clue about the pedal problem.

[CamaroCracka]

Lingenfelter used to sell a return spring for the pedal. The only time I had the pedal stick down was when the fluid got hot racing. That disappeared when I installed the external reservoir with the new clutch. 100k is a lot of miles on a clutch, especially if you are running it hard. Personally, I would look at it as the clutch needs replacing soon anyway so you can either run it until it fails or go ahead and do it on your schedule. Hell, it would probably be a good time to put carbon blockers and synchros in the trans along with bronze fork pads and Liberty bearing kit while it's out, then you have a fresh build going back in that is stronger than new.

[fz4k98]

I have not had a problem with pedal mash but have had two twin disk clutches and am now on a spec 3+. I really love the spec 3+ on my 13 camaro and have 610rwhp.

I spent a lot of time trying to resolve clutches that would not disengage. It appears to me that based on the way the system works the likely driver for the pedal mash issue would be the presssure plate being to weak to handle high rpm centrifigul forces.

The slave is under compression when the clutch is engaged and moves toward extension when the clutch pedal is pressed. If the pressure plate fingers flattened during high rpm, the slave would extend and the fluid draw would pull the pedal down.

[Valkyrie14]

Originally Posted by CamaroCracka

Lingenfelter used to sell a return spring for the pedal. The only time I had the pedal stick down was when the fluid got hot racing. That disappeared when I installed the external reservoir with the new clutch. 100k is a lot of miles on a clutch, especially if you are running it hard. Personally, I would look at it as the clutch needs replacing soon anyway so you can either run it until it fails or go ahead and do it on your schedule. Hell, it would probably be a good time to put carbon blockers and synchros in the trans along with bronze fork pads and Liberty bearing kit while it's out, then you have a fresh build going back in that is stronger than new.

This is a good idea. I am planning on doing the clutch myself. I’m thinking rebuilding the trans may be above my ability. Is it difficult?

[Valkyrie14]

Originally Posted by fz4k98

I have not had a problem with pedal mash but have had two twin disk clutches and am now on a spec 3+. I really love the spec 3+ on my 13 camaro and have 610rwhp.

I spent a lot of time trying to resolve clutches that would not disengage. It appears to me that based on the way the system works the likely driver for the pedal mash issue would be the presssure plate being to weak to handle high rpm centrifigul forces.

The slave is under compression when the clutch is engaged and moves toward extension when the clutch pedal is pressed. If the pressure plate fingers flattened during high rpm, the slave would extend and the fluid draw would pull the pedal down.

I’m not up as high as 610, not sure of my rwhp for sure. I am looking at Monster dual with all of the upgrades. Your explanation of what is happening makes sense.

I am going to quote you when I explain to my wife why I am spending another $2K on my car.

[CamaroCracka]

Originally Posted by Valkyrie14

This is a good idea. I am planning on doing the clutch myself. I’m thinking rebuilding the trans may be above my ability. Is it difficult?

I felt rebuilding the trans was more than I wanted to take on. A guy on the CorvetteForum did have a good writeup, but pulling all those gears off the output shaft did not seem like something I wanted to take on. I sent it to a local shop and gave them parts I wanted used. I even got a 9310 output shaft from RPM before they stopped selling them unless they did your rebuild.

IIRC I got the parts from here https://www.thegearbox.org/tr6060.html

[Valkyrie14]

Originally Posted by CamaroCracka

I felt rebuilding the trans was more than I wanted to take on. A guy on the CorvetteForum did have a good writeup, but pulling all those gears off the output shaft did not seem like something I wanted to take on. I sent it to a local shop and gave them parts I wanted used. I even got a 9310 output shaft from RPM before they stopped selling them unless they did your rebuild.

IIRC I got the parts from here https://www.thegearbox.org/tr6060.html

Nice site, thanks for the link. Considering I have no idea where any of that stuff would go I don’t think I will tackle rebuilding the trans myself either.

[fz4k98]

Originally Posted by Valkyrie14

I’m not up as high as 610, not sure of my rwhp for sure. I am looking at Monster dual with all of the upgrades. Your explanation of what is happening makes sense.

I am going to quote you when I explain to my wife why I am spending another $2K on my car.

Does this mean I can quote you to my wife so she sees someone actually thinks I know what I am talking about?

[Valkyrie14]

Originally Posted by fz4k98

Does this mean I can quote you to my wife so she sees someone actually thinks I know what I am talking about?

Seems fair.

[The_bald_eagle_machine]

I do not personally have experience with this part. But Lingenfelter has a solution for the pedal mash issue that you described and they still have them in stock.

https://www.lingenfelter.com/product/L360091410.html

[Eastbaycamaro]

I will be removing my McLeod RXT twin disks next week and put it up for sale. Got about 15 passes at the drag strip. It is a solid hub design pn# 6932-07