Dkarr

Well... I just installed my rebuilt engine and trans into my 69 and discovered a very disturbing issue. My clutch fork is hitting the firewall with only about 1 inch of travel available. I installed a Lakewood bell and measured the 4.75 inches out from the pivot ball to the block face (I took into account the Lakewood block plate).

So... either I screwed up the measurement or something else is wrong. Anyone else had an issue like this? I assume that the fork pivot ball is not adjusted correctly. I do remember there being a fairly large gap between the throwout bearing and the pressure plate fingers... but this is my first time doing a rebuild so I assumed it was in spec given the measurement I did with the pivot ball. I've included some photos below. Please help.

Hitting the firewall


The total available travel

TimAT

SOmething is off. Trans mount maybe? I've got a Lakewood in my 69 and you could throw a cat between the fork and the firewall/floor. If the rear of the trans or the motor mounts are too high I could see it driving your clearance down.

427Hotrod

You've either got too short of a stud or throwout bearing.

Years ago there were 3 stud lengths and 3 bearings available. Today you can get two of each. You can also get an adjustable stud which is often needed. There is a great throwout bearing available from Mcleod that comes with different thickness sleeves that allows you to make it one of 3 overall lengths. I've got one in my car and it helped get linkage perfect.

With the pedal at rest..you want the throwout arm as far forward as possible without the arm contacting the pressure plate. It should really come almost to the front of the hole and that clutch dust boot might become a problem and keep it from going enough. I've never used one...to me it's just one more nice place to let heat out of there.

JIM

Dkarr

I bought this throwout bearing ( http://www.summitracing.com/parts/CTF-N1716/ ) which was supposed to go with my clutch and was listed for a corvette of my year. Here is my Centerforce clutch http://www.summitracing.com/parts/CTF-DF735552/

I do have the adjustable fork stud from lakewood. I guess my first plan will be to try and adjust it forward. BUT... can I do that with the trans in place? It looks like it may be next to impossible to get at the clutch stud.

Also, since the 4.75 inch measurement is now going to go out the window how should I measure the adjustment? I've heard some say to adjust until you have a 5 to 70 degree angle on the fork with the throwout bearing touching the fingers. Is that legit or should I measure another way?

Belgian1979vette

Hi,

I have a Lakewood I'm going to mount.

Would like to hear what the final hardware was that you used to correct this problem.

BTW : what did you use to close to hole in the housing for the fork. My original one didn't fit.

427Hotrod

The Centerforce needs some room for the fingers to move a little when the weights start tugging on them..plus remember..as the clutch wears...the distance between the TB and fingers gets less. You don't want to get to a place where the fingers are pushing on the TB at rest and no adjustment for freeplay.

You're most likely going to need to pull the trans to get it all right. Not much room in there and you have to make sure the adjustable stud gets really tight and doesn't get loose. I usually tack weld the locknut when I get it right...or at least use red Loctite.

I believe the Centerforce DF uses the *short* bearing...which that appears to be. You're going to want to adjust the stud out toward the engine so that the arm is as far forward as possible without hitting the pressure plate (turn the motor a few times to make sure after it's all back together- there are places on the PP that extend outward) and where you have say 1/4-3/8" space between bearing and PP fingers at rest.

Is it a stock flywheel?

JIM

Zoix

I have the same set up and problem. I was going to cut the floor pan and glass in a relief to get the full stroke of the fork. I know its close to the accelerator pedal but I can make it work. Once the carpet is in you won't know its there. I have the interior gutted anyway.

Dkarr

It's a ram billet steel flywheel. I can get specs later this evening. I am considering taking the engine back out this weekend since nothing is bolted up yet. Seems easier than laying on my back to fix this problem...

gkull

You just have to pull the tranny back and rotate it out of the way of the pivot stud allen.

The correct fork arm/throw out/pivot ball length is when the fork arm is 90 degrees to the shaft at rest and clearing the PP fingers by the recommended amount.

Im running a DFX with the throw out maybe .060 - .080 off the fingers

The block saver/thinner billet steel fly wheel/ Lake wood bell is what I'm running

Belgian1979vette

I had a quick look at my unmounted lakewood with the arm in it and it seems my arm is more to the engine side of the bellhousing...

Dkarr

Thanks for all the input guys. Fixed the problem. The pivot ball was too far back. I'll post more info soon with pics on the resolution. Long story short, my aftermarket flywheel is thinner than stock... I didn't take that into account into my measurement.