Clutch issues

[SLOroadster]

My clutch has gone south. I have bled it at least a dozen times today and still can't get a firm pedal, nor will it completly disengauge enough to shift into or out of gear. Yesterday it suddenly started slipping, and so I bled it and then it wouldn't disengauge enough to shift. I bled it more tonight with the same issue. I'm stumped, any ideas? What is the full throw of the slave piston? The clutch has about 3000 miles on it, as does the flywheel, throwout bearing and pressure plate its self.
Thanks,

Will

[S Allen]

Could be the pilot bushing. Did you replace it when you last had the motor out? Another often overlooked issue is too much play at the peddle. Peddle play is an important part of a clutch adjustment. Any one or several of the following components could be worn. Look at the clevis pin that connects the pedal to the rod yoke coming out of the clutch master. Also look at the hole in the rod yoke. Next check the hole in the clutch pedal for wear. These parts tend to oval out over time providing quite a bit of slop to the whole setup. If any of the above parts are worn, weld or braze them up and re-drill them. Good luck.

Steve

[kt]

curious, when you step on the pedal,
does the slave cylinder piston actually travel?
Is there resistance??

Mine travels about 2-3 inches(from memory).

If it does travel, then bleeding will do you no good
as these are in good shape.

When you do have it running in gear,
is there a rumbling sound from the clutch?
all quiet?

[SLOroadster]

Some times it does make a little noise but not always. I replaced the flywheel, the clutch plate and disk, pilot bushing and throwout bearing all at the same time. I started getting a squeek but it went away. The throw-out bearing started making nose that went away when I pushed the clutch in. I think I have a larger problem than something simple.

Will

[Sloloco]

Now you might have a bigger problem than that darn tapping coming from my pile! Sorry to hear it.

[TR]

Hey Will,

If you want to rule out the hydraulics before you yank the engine out, here is a simple check;

Place a long pull tie around the throwout arm and secure it to the back of the slave. If you don't have a long one, you can put multiple ones together. What you want to do is restrain the arm motion with the ties. Try pushing the pedal lightly, if it is firm on the first stroke (without pumping) you have all of the air out. You should be able to break the pull tie by mid stroke. I have found that it is much easier to bleed the clutch line when the piston is restrained...

Good luck and hopefully you won't have to pull the engine out! TR

[SLOroadster]

I think I somehow managed to break the diaphram spring on the pressure plate. This would explain why the pedal feels like mush even though the system is bled. I even bought a return spring that is about 3X the spring tension, and it still feels soft. Now I need to find a place where I can work (a large garage or warehouse would be sweet.) I think I am going to drop a second engine in while I redo the rings, fix the oil leaks and add some really cool internal parts that are balanced and lightened . I will probably put the SUs back on and get one of my solexs rebuilt. It won't be a hotrod for a few months but when it comes back, watch out!

Will

[Russell Roach]

Will,

I think you are on the right track when I had my engine out this week end doing a cam swap Got everything buttoned up and bled the clutch no ability to get the clutch to work lots of action on the slave cyl but none on the pressure plate. Ok so I pulled the engine back out and the springs on the new pressure plate were much more compressed Yikes! So off to a clutch shop. Shame we found this out after the engine swap good news is new cam has really made the engine come alive good luck I'll keep ya posted on exactly what happens

Russell

[S Allen]

Will,

What kind of clutch and how many miles on it? I heard you drive the snot out of your car. Russ, so tell us about the cam. What kind of a duration and lift did you end up with? How was your experience with American Cam Grinding? Did he grind a stock cam? Thanks.

Steve

[Russell Roach]

Steve,

110% thumbs up for Joe Bray and Americams. I went with Joe's recommendation of his M-36 cam .450 lift and .290 duration. Christ Almighty!!! will this thing run! With the clutch trouble I had to start the car in gear and then grab second Here came 5 grand ...six grand....7 grand I finally got out of the gas at 7500 and the end of the street that my buddy and mechanic lives on. I swear I couldn't get the grin off my face.

Steve I looked up the cam specs and Joes came is even better that what Isky calls their super comp cam(my Ass!) Now here is where I have to be honest my valve train is not stock I have corvair valves(long story) and Chevy valve springs it my understanding that springs with 100/200 pressure can be used with the cam not a problem.

I can't wait my next race is Oct 2-5 I have been running with a stock car that the only mods have been to lighten it to about 1800 lbs that has changed.

1. americam racing cam
2. Aluminum Flywheel
3.Comp springs Front and Back
4. 4.38 locked rear diff with Ron Nash( BRE fame) Spider Gears
5. Competition Clutch and Pressure plate
6. Carter Big Block Gerotor Fuel Pump
7. Huge chip on my shoulder about being picked on by mg's austin's fiats and alfa(notice no caps)

Steve one last thing I think eight grand is possibly because it didn't just go to 7500 it was passing it. I'll know more about horse power when I take it to the dyno in a few weeks.

Man do I feel great!

Russell

[S Allen]

Russ,

That is great news. I may have to try one of those in the race car. Right now all I can get out of her is 6200 and she just runs out of steam. It sounds like you are having a lot of fun racing. I remember from one of your earlier posts that your 1600 runs on the warm side too. Mine runs around 215 to 225 when I run the crap out of her--but I have not had any problems. The R is one tough little motor. Good luck to you and thanks for the input on American.

Steve

[70MTroadster]

Russell,

Dunno if you have been following along my whining, but I am looking for cylinder head mods and how to's for my 70 1600. Your new cam install gets my blood up, I guarantee

Any chance you can post something here on the Corvair valves and Chevy springs you mention? or maybe off site to me?

Any help would be greatly appreciated.

Scott

[SLOroadster]

I am running the Nissan 650Kg pressure plate and the nonpucked disk. Who says that I drive my car hard? Every so often I will run it to about 6000 rpm, but not often and not for very long. Infact 5th gear at 80mph is about 5200. The clutch has about 3000 miles on it. It never slipped untill last friday night. The pedal was firm, never smelled the clutch burning, it just went from good in the morning to not good that night.
That cam sounds fun, My .48 lift 284/290 degree one allows the engine to really pull at high rpm, and the solexs help also.

Will

[Russell Roach]

Scott, Steve and Will,

Oh Lord the strange saga of my roadster and racing on a limited budget. I have a great friend named Tom Vester who is a true disciple of Smokey Yunnick(sp) Tom is a mechanics mechanic I have seen him build everything from Harleys to Air boats( keep this in mind for later) If Tom said he was going to build a Space shuttle outta bailing wire and Bubble gum I'd be the first one in line to fly it. The only thing is that it would be primer gray. He also built the 53 Studebaker that we ran in LaCarrera Pan Americana in 2000 finishing 66 out of 94 teams and Taking second in the 105 avg. Mph class in The Big Bend Open Road Race www.bborr.com


During the process of building my car on a buy as you go build up, Tom found the the valves in my engine were knife edged Oh great I thought here goes another 300 dollars of my money for valves, well after about thirty minutes I get a call from Tom saying I hope you haven't bought those valves yet because Corvair valves will work and I have a set of them...My first thought was ..how in the hell did he know this...and who in God's name would have a set of them lying around( you must according to Tom reem the valves guides out to the diameterfor the corvair valves but thats all the mods the head will need) Then I realized that my crazy mad scientist buddy who was into building air boats and needed a good air cooled engine might just happen to have them lying around.

The next thing I know is that he says we need valves springs and much to my surprise(not really at this point) he says hey don't worry about it stock small block chevy valves springs will work.

Scott I am not sure what spring retainers to use but I will see Tom and ask him for parts numbers The only bad thing about Tom is that he doesn't understand how complex engines can be to guys like me so when I ask for stock valve springs for a small block I get stumped by parts guys in hurry. So I will try to get as much detail as possible.

Steve,

I did have a overheating problem but I have a custom rad and a heater core(Chevy guess who struck again) in the trunk with a fan attached to it. Runs cool as a jewel. Next addition will be a larger water pump pulley made for a (you guessed it Chevy)

I'd also like to get a photo of my car on here but it seems all the ones I have are too big maybe Steve I could send it too ya and have you post it for me.


Russell

[S Allen]

Russ,

I am interested in the head, valve, spring thing too. It must be nice to have a "can do" mechanic for a friend. Sky is the limit hey! I would like to hear how your dyno turns out as well.

Will, I was just kidding about the driving hard. 3,000 miles is not much on a clutch. Let us know what you do find out. I think you are probably right about a diaphram spring or springs going south on the pressure plate.

Steve