68Thunder427

I just installed a new clutch kit and flywheel on my 68 BB and it has a noticeable vibration now. The clutch engages and disengages nice and smooth but this vibration is weird. Any ideas?

zwede

Did you get the correct flywheel? I think you said you have a 454, so it needs to be externally balanced. The original 427 was internally balanced (different flywheel).

marshal135

Thunder,
I have the same car and I have to release my clutch at 1200 or higher rpms or I get an ugly chatter.
Are you coming off the line w/ enough rpm's?
I know you may be scratching your head at this response but if the pressure plate is bolted up securely and the flywheel surface is fresh and not glazed theres not much to these things.
Do you have the 1/2 " freeplay at the pedal?
If so you need a lil more juice to start the wheels in motion.
Mine shakes like it is seizing and feels like I'm going to break something w/o enough pedal at launch time.
Marshal

Revi

Did you use a needle bearing pilot bearing or a bronze bushing pilot bearing? If you used the needle bearing type, you will need to replace it with the bronze type.

I had the same thing with my 70 last week. I pulled the clutch a second time, didn't see anything really wrong with it, re-installed, had someone push in the clutch while pushing in the M-21. It popped right in, smooth as butter now.

mysixtynine

What type of clutch? I've heard a few issues with the centerforce pressure plate with the centrifugal weights causing issues.

What flywheel? You didn't mix a externally balanced flywheel with and internally balanced motor or vice versa?

ignatz

My Centerforce combo required dowel pins to correctly index the pressure plate. With those installed, no vibration even with the weights in place.

68Thunder427

I installed a LUK clutch kit from Napa since that was what was in it originally. The throw out bearing may be a needle bearing type will have to check that to, it did have a plastic liner where it goes onto the shaft and it was metal not bronze. I will double check the flywheel type to make sure it is correct also. It does seem that flywheel / clutch is out of balance.
As far as operation of the clutch it functions fine and right now I have about 1 1/2" free play and going to adjust it up tighter if I am not pulling it all back apart based on responses and a little more checking. The clutch releases fine about an inch or two off the floorboard.

68Thunder427

Help me figure out this engine if you can here are the numbers on it:
BLOCK T0821TRT T4F500816
HEADS 3964291 HI PERF GMGT
INTAKE 3885069

Danish Shark

http://www.nastyz28.com/gm-chevy-cod...-suffix-15.php

TRT reads as 1974/1974 truck 454, so if it still has the original internals it would need a 454 flywheel.
Why don't you compare the new one with the old one?
Look here for a side by side comparison of external vs. internal balance flywheels (scroll down):
http://www.chevelles.com/forums/showthread.php?t=328871

Even if you have the correct flywheel you may have to get the new flywheel/clutch kit balanced to match the old kit.

Revi

The pilot bearing goes into the back of the crankshaft and is a press fit. The throwout bearing fits on to the clutch fork and disengages the clutch.
I used a LUK clutch as well. When I took it apart the second time I replaced the plastic/carbon fiber LUK throwout bearing with the old "all steel" throwout bearing. (No idea if that was the cause or not.)

68Thunder427

I was tired when I read that post and responded and yes the pilot bearing is brass.

68Thunder427

I believe you are right about having to get this new set balanced but either way the it is coming back out which sucks but such is life. Keep on keeping on

doorgunner

EDITED:


68Thunder......do you still have the (old) original set-up to do as he suggested?

68Thunder427

I do have the old set up and I have no clue who to take this thing to to get it balanced.

68Thunder427

May just get the old one resurfaced and put it back in. With that said is there something that needs to be done to make sure it is balanced with the new clutch assembly before putting the motor back in?

doorgunner

I'm thinking the other member is suggesting that you take the old assembly to the repairshop.....let them examine it.....then they can balance the new assembly to match the old assembly (while you are there....let them resurface the old plate after they balance the new assembly/then you have a "standy-by" clutch plate/win-win!).

68Thunder427

So I pulled the engine back out and removed the new clutch and flywheel. Come to find out after calling the parts house and by dumb luck I figured out they charged me for the right flywheel but pulled the wrong part, should have been a 1041 but was given a 1014. So I get the correct flywheel and start back in with the install. I get down to the last bolt of the clutch pressure plate and snap the bolt breaks. I am so dam frustrated and tired of working on this car right now I can't even think straight. If it were easy then I guess anyone could do it but seems like trying to go 12 rounds in the ring with a heavyweight boxer sometimes.

doorgunner

THAT SUCKS! but I guess you already know to drill all the way to the bottom of the broken bolt with a slightly smaller drill--taking your time----and using a bolt extractor to tap into the drilled hole and unscrew the broken piece.

Take a break....you're almost done.....you can DO IT!

68Thunder427

It does suck and yep already getting drill bit, easeout, and new bolt gathered up.

croaker

I'm planning a clutch job now and was thinking why would you have to balance a brand new clutch in a fairly stock car. I searched and found a Hays guide and they do suggest a balance job done. Never done it in the past 2 I've done on other cars. I'm already losing sleep over product quality issues.