Odd Clutch Behavior (Ke30-7K-K40)

[Chairs with Flares]

So I just put a new Exedy HD/SportTuff clutch kit into my KE30, which is running a 7K on twin Solex's backed by the standard K40 4-speed trans.

 

I got everything together without issue and managed make an additional firewall spacer for the clutch cable and the car drives fine and the new clutch does all the clutchy things a clutch should do.

 

Except for one thing... If I hold the pedal all the way down for a while; say 40 secs; (I know, I know, just put it in neutral), a little smoke starts coming out of the bell housing. Not a lot of smoke, and it doesn't smell like anything really, not burning clutch plates, not burning oil or plastic or resin... Perhaps a similar amount of smoke as a match after you blow it out?

 

At first I thought the pressure plate might not be fully disengaging, but I adjusted the pedal to hit the limit of clutch fork movement juuuuust before the pedal hits the floor, so it's not like I'm 'losing' any pedal travel. Another test for clutches not fully disengaging is clunking into reverse as there is still rotational motion in the gearbox, which it doesn't do. The trans gears are definately stopped when the clutch pedal is down, shown by the [straight cut] reverse gears either meshing when the teeth line up or just not when the teeth don't line up.

 

I'm just kind of stumped now. I'm not one to hold the clutch down for extended periods of time , but little things like this bug me. Thrust bearing cooking? (Shouldn't be, the kit came with a new NSK unit)

 

Anyone with thoughts or inputs?

Edited February 16, 2013 by Chairs with Flares

[CorollaFan]

Souns like a bit of oil burning, did u clean pressure plate properly before installation?

[Chairs with Flares]

Souns like a bit of oil burning, did u clean pressure plate properly before installation?

 

I thought it may have been left over cosmoline or whatever is it they use after manufacture, butI did give all the plates a good clean. The only thing left may be a little residue from the part # sticker on the pressure plate. If it is, time will tell as it would slowly burn off with use.

 

The thing that gets me is the lack of smell the smoke has. Oil and clutch are pretty distinct smells, this just kinda smells like hot...

 

-Jeff

[NinjaMekanik]

. The only thing left may be a little residue from the part # sticker on the pressure plate.

 

Does that mean you left the sticker on or you didnt clean it after you removed the sticker?

[Chairs with Flares]

 

 

Does that mean you left the sticker on or you didnt clean it after you removed the sticker?

 

I took off the sticker and cleaned up the gummy residue with acetone. There was a slight discoloration where the sticker was on thr pressure plate face though.

 

[NinjaMekanik]

ok good. How many k's do you think you've done so far with the new clutch??

[philbey]

Given that it's when you put a foot on the clutch, about the only part doing any actual work is the thurst bearing. The thrust bearing is probably packed with a grease from the factory, and it might just burning off/vapourising any excess in it. Often new industrial bearings can run hot when you first run them and they "bed down" etc,

 

I wouldn't worry about it. If it's not noisy, it will be fine.

[Chairs with Flares]

Kinda long, but I've had somewhat of a revelation.

 

I've done about 300km driving to and from work on the new clutch setup now, and it seems the smoke is getting less everytine I check. I've narrowed the smoke down to my own mistake of over greasing the clutch splines (old habit from wrenching on old BMW motorbikes). I stuck my anal probe/boroscope and some fingers into the bell housing and found a film of grease on the pressure plate fingers, which could only be the included tube of grease in the clutch kit. Further testing of heating up some of that Exedy grease and comparing the similar smells (faintly rubbery) of smoke would suggest that it's the excess grease burning off. Being an HD clutch, I'm guessing that even if some got onto the friction materials, the additional clamping force of the pressure plate is still holding under torque.

 

I don't really abuse the car too much as it still has the stock K40 and diff. No hard launches and I make sure everything is loaded up before the berries are given, so to speak.

 

The thrust bearing is now making an occasional 'sshhh' noise on contact. Having a feel through the clutch arm hole (conveniently easy on a Corolla), the bearing feels fine with no play or crunchiness and my anal probe camera showed no discoloration from heat or anything irregular. I'll keep an eye/feel on it and see if anything develops.

 

Thanks all for the input and happy travels.

Edited February 20, 2013 by Chairs with Flares