squarehead

I was having some fun with my car this afternoon and ripping through the gears, going some what near redline (i don't race this car) and suddenly it would not go into gear. I was able to nurse it home, really pushing to get it to go into gear, but the clutch felt really jumpy (not sure if thats a good word, shaky might be better). It seemed to not want to go into gears that were significant rpms different from the speed I was traveling if that makes any sense.

The clutch has never really impressed me since I have owned this car so if it is shot I would not be surprised.

However I have learned not to trust my own diagnostic skills when it comes to this car and wanted to post this before I decide to buy a new clutch and grub around under the car.

Thanks for any feedback!

JakeRobb

In addition to the clutch itself, check your master and slave cylinder, and the hydraulics in general, for leaks. What you're describing sounds like the clutch isn't fully disengaging when you press the pedal.

squarehead

Thanks JakeRobb, I will do that later today and report back.

Injuneer

Is it any particular gear that it won't go into, or all gears? Going into a gear that changes the RPM significantly requires healthy synchros and blocker rings. You can overcome that problem with "double clutching" it, if you are familiar with that technique.

squarehead

Thanks for the post injuneer. I just had a second chance to investigate and here is what I found out:

No visible leaks from the hydraulic system, fluid level is just where I filled it a month or two ago (I regularly change the clutch and brake hydraulic fluid to reduce the chance of water contamination), and it feels about right with free play and pressure .

I drove the car to try double clutching and just looking for better information to pass on. It started out almost normal but difficult to move from first to second at low speed. I took the revs up in second and had a hard time getting it to come out of second when I tried to move it to third. It felt like when I let off the gas it decelerated the car as I fought to push the stick forward. I tried raising the rpms and it moved out of second better. I had to hunt around for the better rpm match for it to go into third.

I tried double clutching and it may have been a little easier to move into gears.

I stopped and turned around to head back home after a mile or so and I could not get it into reverse (it had gone in normally when I first backed out of the garage). I had to roll backwards on a slight slope and then go to first which was not easy at all to get to engage. The ride home was pretty much as I had described.

When I was going slowly down the driveway to the garage the clutch made a growling sound when I was pressing the pedal and engagement was very jerky.

Thanks for any insights you might have.

squarehead

JakeRobb, On the chance that I do need a clutch I have been looking around and thinking of getting a lightened flywheel. I noticed in another thread you mentioned buying a ACT unit from Amazon. When I search there I can not find one without Amazon telling me it won't fit my 95 Z28. Do you remember the part number of the one you got that fit your LT-1?

Amazon does offer a Fidanza aluminum flywheel that is supposed to fit the LT-1, any thoughts on one?

Chimera96

OP

lighter FW's can benefit auto x racing if that is your main thing as they allow quicker revving. With that said a lighter FW means you need to keep the revs up slightly on starting in 1st as the "inertia" that a standard FW/clutch have (weight) helps absorb the initial engagement of clutch. If drag racing or just daily driving are you dominant car uses, get a steel or standard weight FW IMHO

on your clutch issue...you need to pull it to see condition. Generally failing hydraulics cause the disengagement issues you have but "use & abuse" can also

for stock motor cars a good "replacement" type clutch is fine. NAPA clutches are LUK.

Any LT1 clutch kit has the clone LT4 PP. Just disc construction varies more so when you get into "level" 2-5. More aggressive clutch disc material (non organic) do provide more holding power but the trade off for street driving often is "chatter" (car shakes on clutch engagement from a stop) so chose a clutch suited for your power level but understand the more aggressive clutch materials, especially "puc" type discs have drivability trade offs

squarehead

Thanks for the feedback Chimera96. It sounds like I will need to take the trans out and check the condition of the clutch to know what is causing the problem.

JakeRobb

Hi, sorry for taking a while to get back to you. Work stuff has kept me away from the forums for a few days.

My car has an LS1, which uses a different flywheel/clutch than the LT1. I don't think my ACT flywheel is available for the LT1.

The Fidanza aluminum flywheel is even lighter than my ACT, and I have heard good things from a variety of people. Note that lightweight flywheels make it more difficult to get a car moving from a stop. If your favorite kind of racing is drag racing, you might not want to get a lightweight flywheel at all.

squarehead

Thanks for the reply JakeRobb. I should have checked your signature more carefully!

I have been dithering between a regular stock set up and a lightened set up. The Hour of Decision is quickly approaching and I will probably just get the stock set up. The car is just a daily driver and in my sober moments of reflection I realize that is how it should stay.

I did take the trans out yesterday and have the clutch and flywheel out. The friction disk is cracked in a couple places and the flywheel and pressure plate are discolored and worn. Otherwise I have a hard time convincing my self that I have found an attributable cause for the failure to shift.

My plan is to install a new clutch kit and flywheel then reassemble the car. I'll post again after I have driven it and let everyone know how it is working out.

Chimera96

the disc should not be cracked. If so it likely distorts causing it to not disengage, thus your shifting problems

on install torque the PP bolts to 22 ft lbs, any more will cause disengagement problems

FW bolts TQ to 76 ft lbs

squarehead

Chimera96, thanks for the torques specs. I had the flywheel right but had to redo the pressure plate.

I just got back from a successful test drive, the car runs sweet again!

I ended up using the Napa standard clutch kit (Luk $240) with a new Napa flywheel ($140); with dexron trans oil and a slide hammer type pilot bearing puller I spent about $475 for the repair.

Thanks and blessings to Chimera96, Injuneer, JakeRobb and all the folks at camaroz28.com for helping me get back on the road!

Chimera96

good you are back on the road.

drive "normal" for the first 500 miles on the clutch so the disc can bed into the FW & PP.

avoid "slipping" the clutch if you can

squarehead

Will do, thanks again!