MetallicaMatt

iTrader: (19)

I'm using a Spec 5 clutch I've had for awhile. When I very first got it years ago, I used their shim, it didn't work right, so they said take it out. I'm also using a Quicktime bellhousing now, and I measured 1.940-1.960" from the bellhousing to the fingers. (Actually I forgot to subtract the thickness of my square, I'll measure that tomorrow).

I didn't measure the throwout to trans yet. Do I have to remove the spring? I would think I can just bottom out the slave and measure that? But since it's a factory trans and slave now, they all should measure about the same.

-What are others getting for this measurement? Need to know if I need to use Tick's shim.

-What happens if I add the shim but really dont need it? (Even though I saw the thread said "every" spec clutch will need the shim).


Thanks guys,


p.s. - shim is from Tick, 0.115" I think

DAVESS02

iTrader: (30)

Make sure you open the bleeder on the slave so you get an accurate measurement. It wont bottom out otherwise. I have someone else take the measurement while I depress the slave. After I'm done, I bench bleed the slave to get as much air out as possible. When all is said and done, if you have less then .220, I wouldnt use the shim you have. I like at least .100 gap, preferably a little more, considering the fingers move out during wear of the clutch.

For reference, my last one went like this:

2.152
TO bearing to mating surface of the trans:
extended- 2.887
fully compressed-2.021
air gap-.131

MetallicaMatt

iTrader: (19)

Thanks Dave!
I'll have some stack up error in how I measured the slave to transmission distance. I measured it without the slave mounted to the trans, but the numbers should be good, other than stack up error and trying to measure a casted surface. I'm used to measuring 0.0001" at work...so this made me grind my teeth a little bit lol.

So, bellhousing to clutch fingers 1.873-1.893"

Throw out to transmission face ~2.088 (throw out fully compressed)

Assuming my numbers are correct, according to Tick's write up, "If there is no difference between the two measurements, or if "B" is greater than "A", there could be a problem with clutch engagement which could result in premature clutch slip and eventually a total failure.
"

So since my "B" is greater than "A"...I have a clutch engagement issue?

If I'm thinking correctly, this would mean that my clutch will always be slightly engaged?

On the slave I just took out, I could shift into gears on my lift, with ZERO grinding of the trans. It would make a noise, when I had the clutch pedal in, in neutral and just rev'ed the car to about 3k. It sounded like a bad pilot bearing, but I changed the slave also just incase.

Thoughts before I stab this all back together?

MetallicaMatt

iTrader: (19)

Which, this all doesn't make much sense, since everyone said you "must" use a shim with a spec clutch.

I can't imagine this clutch has worn that much in the short period of time I've used it.

MetallicaMatt

iTrader: (19)

Light bulb came on. Quicktime gave me an aluminum plate to go between the housing and the block. It didn't fit right, it was cut wrong from the factory, I tossed it aside. By adding the plate back, that would increase the distance from the bellhousing to clutch fingers. But I don't think it was more than 0.125" thick

So far, I'm in the negative...?

I used calipers, maybe I should dumb it down and use a scale and eye ball it.....

MetallicaMatt

iTrader: (19)

Bump!

MetallicaMatt

iTrader: (19)

So, I measured the quicktime bellhousing/engine block plate, it's 0.125" like I thought. So, now my new numbers are

Clutch to bellhousing: 1.998 - 2.018
Throw out bearing to trans: 2.088

So, still "negative". But, I know I have measurement error in the throwout bearing measurement, but I don't think it's that much. Is this OK since it's a clutch I've used?

It appears I DONT need a shim with my SPEC then....

Opinions and suggestions? I'd like to throw it back together tomorrow....

DAVESS02

iTrader: (30)

Personally, I've never seen a PP to bellhousing measurement that low. I've always had a higher PP to bellhousing measurement then slave bearing surface to transmission mating surface.

"If I'm thinking correctly, this would mean that my clutch will always be slightly engaged? "

Actually your clutch will always be slightly DIS-engaged and more prone to slipping. I bet engagement is real high up on the pedal.

Have you talked to Spec? Maybe the disk is worn too thin? If so that would let the fingers extend too far out. The only other thing I can think of is a problem with the flywheel?

MetallicaMatt

iTrader: (19)

Typeo on my part, we're on the same page, it would be dis-engaged slightly.

I have not talked to Spec. The disc looked pretty healthy and the flywheel looked fine, I couldn't even catch my fingernail on where the clutch touches and where it doesn't

scratching my head on this one! I measured from the flat spot on the clutch "fingers" to the surface of the bellhousing.

The only thing I can think of, is that the Quicktime housing is to short?

DAVESS02

iTrader: (30)

Too bad you dont have a factory bellhousing to compare. At any rate, I'd call Spec first.

MetallicaMatt

iTrader: (19)

I still have my factory one around here. Im going to dig it out tonight and measure.

I emailed spec this morning, but no response yet. Didn't look like a good phone number on their site for tech help either

MetallicaMatt

iTrader: (19)

If the bellhousing is to short I could shim it between the block. That wouldn't be ideal but it would work. No idea why the measurement would be short, clutch looked ok.

Worse comes to worse, I have to get a new clutch I guess....ugh

MetallicaMatt

iTrader: (19)

I called spec and they are closed for a holiday??? What the heck!

What distance were you getting, clutch to bellhousing?

I wanted to put it together tonight...not sure what to do from here...

MetallicaMatt

iTrader: (19)

I called spec and they are closed for a holiday??? What the heck!

What distance were you getting, clutch to bellhousing?

I wanted to put it together tonight...not sure what to do from here...

25thhawk

iTrader: (3)

I would definitely try mounting the slave to the trans and remeasuring. I did mine a while ago, but I think my measurement was around 2.000, maybe a little less. And my pressure plate to bellhousing was closer to 2.480, also using a quicktime bellhousing, with the engine plate. There is definitely alot of difference in slave cylinders. So before I bought a new clutch, I might see if I could find a shorter slave cylinder. Good luck

Ryan

MetallicaMatt

iTrader: (19)

Im using the stock GM slave from Tick. Should be perfect?

HP52TA

iTrader: (6)

I just went through this as well. I had purchased a used RAM Powergrip HD that came out of a functioning 4th Gen for my LS swap. (due to budget constraints) When I went to install it, I was measuring about 0.200" of dis-engagement at the pressure plate, with the QT bell.

Replaced it with a new ACT GM9-HDSS clutch with everything else being the same and ended up having to install my 0.125" shim behind the slave cylinder to decrease the clearance down to 0.185". Disc and PP wear greatly effect these measurments. (I used Ticks measurement process as well for these checks)

If your pressure plate is not worn too bad (check for wear using a straight edge across the clutch mating surface) you might be able to get away with just a new disc. If the PP is worn badly, I would go with a completly new clutch all together. If going new, resurface your flywheel too for best results. (Cheaply done at your machine shop)

Mcleod does make adjustable slave cylinders, but that would only be a band aid until the clutch was completely worn out.

If you install it as is (not recommending this) it will likely work fine for a while, but a new clutch will be in your near future, especially if you run it hard.

MetallicaMatt

iTrader: (19)

Qt bellhousing and stock measure the same. Must be the newish spec clutch! Crap!

MetallicaMatt

iTrader: (19)

Results from tonight....

Quicktime Bellhousing and Factory Bellhousing measured the same Overall Length.

Friction plate on the clutch was evenly worn, and measured a thickness of 0.309" on every pad. Hopefully SPEC will chime in here.

I'm guessing this clutch must be shot, which is EXTREMELY disappointing since it has very little miles on it, and maybe 5 passes over it's life. I didn't even drive the car last year!

25thhawk

iTrader: (3)

There is alot a variation between slave cylinders. Doesn't matter if they are new or gm parts. Just the way they are made. The few I have measured were up to .100" different. Also I saw one that had a black metal spacer glued to the back of it that was .100" thick. Compared to the ones I have done, your slave to trans measurement is about .05-.08" larger and your pp to bell is about .250-.400 less. I think Jason from Texas Drivetrain also sells bellhousing spacers. But I think this is a band-aid for your situation.