Clutch won't stay adjusted

[Lynn]

I have a CNC slave cylinder on my Solo Vee. It will not stay adjusted. I can get it adjusted with good pedal feel and it works great from the grid to the start, launch and shift to third. But by the time the run if finished, the clutch doesn't want to release. It takes some effort to get it out of third and it won't go into second until the car is stopped and the engine is shut down. Then, if I depress the pedal and try to start the engine, the car lurches forward and fires up in gear and goes its merry way. BTW, don't reach through the headers to adjust the clutch unless you are wearing mechanics gloves.

Any advice will be greatly appreciated.

[FVartist]

Read Brian's post under clutch lever. It could be a possible reason.

[FV80]

There are basically 3 possible reasons that I can think of.
1). You have a leak in the line and are loosing fluid. (should be obvious, so probably not it)
2). You have a leaking seal INSIDE the slave *AND/OR* master cylinder - rebuild both ends to be sure.
3). Your clutch line is TOO close to the exhaust header and is boiling the fluid in the line as the engine revs up. (build an aluminum shield for it or reroute it).

Good luck,
Steve

[DanRemmers]

I've always had problems where the hemispherical nut on the slave cylinder shaft interfaces with the hole in the clutch lever. Sometimes it nestles in the hole nicely, and other times it rides up on one side which changes the adjustment by about 3/8".

Check and see if you have the same issue. If so, you will have to bend the clutch lever, or relocate the slave cylinder. I've thought of running a short cable from the slave cylinder shaft to the clutch lever just to add extra flexibility, but that seems too complex.

I've adjusted my clutch so many times in between runs that I only get 1st degree burns now.

[brian]

As was mentioned, check the alignment of the ball nut and the opening of the clutch arm. Even though I will bend the arms to align them I use anti sieze in the socket to prevent sticking. The a/s is resistant to heat and won't melt.

[Lynn]

Thanks for all the replies, gentlemen. I did check out most of your suggestions, but it turns out that the only problems were the slave cylinder need to be bled and I was adjusting it the wrong way.

It worked fine at the National Tour this weekend. Now, I just have to fix the problem of spinning the inside tire accelerating out of the turns. And then that is that little problem with having no talent.

[brian]

A little less preload on the z bar might help the tire spin. Back in the day of early go karts, we used to lean way outside the cockpit to leverage the wheel a bit but I would imagine that would be frowned upon nowadays.

[Lynn]

Brian, it is a zero roll car. It did have a rear anti-roll bar but that has been removed. The solo rules allow limited slip differentials, so I'll be buying one soon.

[brian]

It could be cheaper to lock up the spider gears if you don't mind a locker. I'm surprised a zero roll car is spinning the tires. Guess it's not due to lifting a tire just all that power you guys have.

[Lynn]

In the 70's, I pushed more stock cars with welded spider gears through more pit areas than I care to remember. Even though the Vee is almost 3000 lbs lighter than some those cars, I think I'll go with the LSD.

My solo vee has 109 hp at the wheels according to the SRacing chassis dyno. And it has lower gears in the transaxle with 20" diameter tires.

[billinstuart]

Had a Datsun 510 with welded diff. It was brutal at low speeds..even it wanted to push. I'd think a vee with a welded diff would be impossible to drive at low speeds/autocross.

[brian]

That's great hp Lynn. I can understand why you spin the tires. A locker has no effect until you want the rear tires to go around a different radius. I think AUTOCROSS with it's tight turns may be an issue. A locker, or live axle set up like F500 and old DSR's really do contribute to a push.

[remmers]

i'm curious to see if the inside tire spinning could be resolved with chassis setup, as i have the same problem with my completely stock MGB, and i don't care to move up a class over a $5000 LSD.

[Lynn]

I asked some of the people at our last autocross if they saw the tires spinning. They all said no. I started using a muffler this year and now I think what I am hearing is just the normal sound of racing tires. I'll ask them to take a closer look this weekend. A properly driven solo vee with zero roll suspension on 9.75" wide R25B's probably should not be able to spin the tires.

BTW, the clutch problem is the slave cylinder needs to be rebuilt.

[vreihen]

A properly driven solo vee with zero roll suspension on 9.75" wide R25B's probably should not be able to spin the tires.

FWIW, my non-zero-roll Vee with no Z-bar was easily spinning 13' *wide* R25A's the day I was playing with a set of borrowed monster wheels. The camber shift when the rear squatted down under acceleration caused only about 4" of tread width to be in contact with pavement from the pictures that I have, which obviously isn't good for forward traction.....