New 383 and bad clutch hop/ jumping at take off. Please help

[steveo3318]

Ok. Got my new 383 installed and everything it great. Brand new 12 inch heavy duty clutch. Just a stock replacement 180 dollar clutch. It does have a ram Sfi steel flywheel.

Here's the problem. Anytime I take of in first or reverse and try to slip the clutch it grabs/jumps/ hops the truck bad until I am completely out on the clutch. If I just quickly dump the clutch it is not as bad but i don't want to be spinning and chirping the tires every take off

Motor put out a little over 450 hp on dyno, full roller motor. Cam is 294/308 510/510. 226/234 lift at .50. Has 373 gears. Saginaw 3 speed. I am thinking it's the cam doing it. Can anyone please drop some knowledge on me about what's going on. Clutch pulls hard. Does not slip a drop and is perfect other than jumping

[geezer#99]

It's your pressure plate fingers!
They aren't all equal height. Common problem with a stock pressure plate. Diaphram style is like that. Solution is spend more money (double) and get a higher quality or change to a borg&beck 3 finger style.

[Lee H]

What is the condition of the flywheel? New, old, resurfaced? Any oil dripping from the inspection cover?

[steveo3318]

Flywheel is brand spanking new. No oil on anything. Everything has less than 500 miles on it. I have been told to give it at least 500 miles to break in correctly. Just seems to be chattering to bad for it to clear up after 500 miles to me.

I thought I was doing good by getting the most expensive clutch from auto zone lol. Anyone have any good suggestion on a decent clutch. It's not a race truck and I can't handle this chattering while taking off. Makes me look like I have never driven a clutch.

Also when I installed tge clutch all the fingers pulled in equally. But that does not mean something has not happened.

Lastly I must mention there is a rotational noise slight knock with the clutch depressed in. Any ideas

[Lattimer]

I know if you don't torque it in a star pattern you can get the pressure plate uneven and cause chatter like that.

I have a Street Slayer kevlar clutch (came with the transmission) and it took about 3000 miles to get it so it doesn't chatter all the time, just sometimes now if I let it out too slow.

I have a knock when my clutch is pressed in also, and it took me a long time to find it, but my z-bar touches the header tube when the clutch is all the way to the floor. If I let it up a half inch the noise stops. I found it when I noticed a mark on the header tube and figured out what was making the mark.

[steveo3318]

I am going to run it a while and see what happens. Any thoughts on proper clutch break in???? I have not been hard on it but it does pull hard and the hd model clutch I got feels like a one ton log truck petal it's so heavy to push lol

[70blackfish]

I would say your motor has nothing to do with it, but it will find the weak link. like if you floor it in gear the clutch might not hold...why build a motor and not the rest of the drivetrain ???

[steveo3318]

The rest of the drivetrain is coming. I don't want to change the shifter from the column. I am going to do a m22 4 on the tree conversion eventually. Another thing is I was under the original impression my build would be a 10 to 1 compression about 325 to 350 hp. When it turned out 11.1 and 470 hp on the dyno all clutch parts were already sitting in the shop. The clutch holds perfectly under all throttle. It will break loose with ease while in second and just rolling into the throttle

[airdale94]

A easy to seat your clutch is from a 20mph roll with your trans. in 3rd gear push your clutch in and rev your engine to 4k RPM and dump your clutch sharply. This is a factory service procedure from GM.

[steveo3318]

Originally Posted by airdale94

A easy to seat your clutch is from a 20mph roll with your trans. in 3rd gear push your clutch in and rev your engine to 4k RPM and dump your clutch sharply. This is a factory service procedure from GM.

DDDAAAAAAMMMNNNN. on the third gear 4k drop lol

[airdale94]

Originally Posted by steveo3318

I was under the original impression my build would be a 10 to 1 compression about 325 to 350 hp. When it turned out 11.1 and 470 hp on the dyno.

What heads are you running?

[steveo3318]

World product 2.02 exhaust 1.6 intake. 1.5 roller rockers torqures 67 cc

[Oldtruckfanatic]

Did you check the pilot bearing or bushing when you had it apart? I Know the clutch kit comes with a new one but I usually check it by sliding it on the input shaft of the transmission before I install it. If the transmission is well worn it doesn't take much slop at the pilot bushing to cause a pretty bad clutch chatter. My experience with uneven fingers has normally been fairly smooth operation cold and chattering hot. I'm not saying a warped release plate wont cause the problem I'm just saying the ones I have repaired usually worked OK cold and got worse as the friction surfaces heated up. After a few trips they got hard to drive hot or cold. Once it overheats a couple of times no matter what the cause is you'll be doing it again. Also just a note. I have had bad and broken springs and bad release plates from several parts store clutch kits over the years so its not a bad idea to address it while they will still warranty the parts.

[steveo3318]

Yes I checked the bushing on the shaft and it was a nice snug fit bit still spin with ease. The kit came with a bearing and a bushing. Should I of used the bearing instead?

[steveo3318]

It definately horrible in reverse.

[Oldtruckfanatic]

If it were mine I'd probably pull it back apart and warranty the.clutch set, inspect everything and try again.

[steveo3318]

Originally Posted by Oldtruckfanatic

If it were mine I'd probably pull it back apart and warranty the.clutch set, inspect everything and try again.

Prob what's about to happen. And suggestions on a good clutch setup to go with?

[BLT gmc]

Did you install the engine and trans a a unit? Or did you install the engine with the trans in the truck. I have accidently bent a clutch when installing an engine that did not line up well. Tried lowering and raising the engine and trans, unfortunately the input shaft was just started enough in the clutch disk that I bent it just slightly. Needless to say I had to by more parts and redo that job.

[steveo3318]

Trans was in the truck. I install the engine by my self and it did give me hell lining everything up to say the least. I will pull it down.

[geezer#99]

Originally Posted by steveo3318

Prob what's about to happen. And suggestions on a good clutch setup to go with?

Do it once, do it right!
Centerforce is the way to go.
http://www.summitracing.com/int/part...del/c10-pickup