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Discussion Starter · #1 ·
My brother has a 69 Camaro with a 454 external balance basically stock motor. It is the mid-80's motor.

It came with a Saginaw 4sp and my my brother switched it to a Muncie. He got a new Jegs flywheel, Centerforce clutch (Centerforce KCF524816 ). After re-assembly it had a bad vibration that increases with rpm. Remove the pressure plate, re-install trans and the motor runs out smooth with the new flywheel.

The pressure plate appears to have too much run out as the flywheel turns. Not much but it does have some run out. Centerforce tech told my brother that 3 of the mounting bolts have a bigger shoulder and fit more precise in the pressure plate thereby mounting it properly centered.

I called the same tech and he told me all the bolts were the same and that we needed to re-orient the pressure plate to the next set of holes and try it again. What...I have never heard of having to trial and error a pressure plate until you find the orientation in which it doesn't have vibration. I call BS on that.
It could be the Jegs flywheel is drilled a little off, that would surprise me. Could be the Pressure plate is drilled off or actually not balanced correctly. The car is on the lift in a local shop now and we figure Monday morn to check the mounting bolts closely to see about this "difference". Next step would be to go to NAPA and just get a new flywheel and clutch and send all this expensive stuff back to Jegs.

Anybody got any ideas or have run into this before? Are we overlooking something simple??

thanks guys
 

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My brother has a 69 Camaro with a 454 external balance basically stock motor. It is the mid-80's motor.

It came with a Saginaw 4sp and my my brother switched it to a Muncie. He got a new Jegs flywheel, Centerforce clutch (Centerforce KCF524816 ). After re-assembly it had a bad vibration that increases with rpm. Remove the pressure plate, re-install trans and the motor runs out smooth with the new flywheel.

The pressure plate appears to have too much run out as the flywheel turns. Not much but it does have some run out. Centerforce tech told my brother that 3 of the mounting bolts have a bigger shoulder and fit more precise in the pressure plate thereby mounting it properly centered.

I called the same tech and he told me all the bolts were the same and that we needed to re-orient the pressure plate to the next set of holes and try it again. What...I have never heard of having to trial and error a pressure plate until you find the orientation in which it doesn't have vibration. I call BS on that.
It could be the Jegs flywheel is drilled a little off, that would surprise me. Could be the Pressure plate is drilled off or actually not balanced correctly. The car is on the lift in a local shop now and we figure Monday morn to check the mounting bolts closely to see about this "difference". Next step would be to go to NAPA and just get a new flywheel and clutch and send all this expensive stuff back to Jegs.

Anybody got any ideas or have run into this before? Are we overlooking something simple??

thanks guys


I once had a similar issue with my 454 back in the 70s. It was determined that the clutch/pressure plate assembly was out of balance. The clutch pressure plate balance was corrected by adding some small welded mass corrections tot he clutch - problem resolved. We had the luxury of having the entire engine rotating assembly being balanced due to new pistons and was in the balance machine when the issue was discovered as the clutch was added to the assembly. My shop always balanced engines less clutch, then added an rechecked as standard practice since clutch could be changed at some point. And... all bolts are identical. I would get my money back and buy another clutch.
 

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which flywheel is the big question; it is what needs to be correct for ext.bal.454...
the pressure plate and clutch are neutral balance for use with any 6, v8 eng. basically...
 

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Discussion Starter · #5 · (Edited)
New Jegs flywheel. JEGS Performance Products Flywheel for 1970-1990 Big Block Chevy 454 JEGS Performance Products 601270

Motor runs smooth with this flywheel and no pressure plate bolted up, no vibration. Vibration starts when pressure plate is bolted up and it seems to not run true, but have very minor run out from running true. Slightly off center, perhaps.

Nobody here ever heard of having a couple flywheel bolts that have a bigger shoulder and precisely center the pressure plate? I have never heard of that, but it is what the CF tech said. He also told me in a later call all the bolts were the same. Then he said the pressure plate may need to be relocated 60 degrees to the next holes and that it might smooth then. I think that is all BS. I've never had a pressure plat that didn't just bolt up, period, no special bolts or changing holes till it is balanced properly.

This combo ran smooth before the clutch and flywheel was changed. It had no vibration, now with the flywheel replaced it is still smooth, but the pressure plate throws it off and the vibration starts. Any of you guys ever had to do anything special aligning a pressure plate to an externally balanced 454?

thanks
 

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ok,
I have had several customers over the years that had vibration issues with Centerforce clutches. Replaced clutch and vibration was gone. The centerforce clutches are virtually impossible to balance due to the crazy weights they have on them They have to be right from the factory.

Basically you need to replace the pressure plate. Personally I would go with a different brand.
 

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Discussion Starter · #7 ·
Bill, you were one of the guys I was hoping to hear from. I knew you had a lot of experience with all of this. Sounds like the best first step is to just get a new clutch assembly from another manufacturer and see what happens.

thanks
 

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Bill, you were one of the guys I was hoping to hear from. I knew you had a lot of experience with all of this. Sounds like the best first step is to just get a new clutch assembly from another manufacturer and see what happens.

thanks

Yup,
If it is fine without the pressure plate bolted on then there is really not much else it can be.
 

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Discussion Starter · #9 ·
Center Force clutch is replaced with a NAPA unit and vibration is gone. Bad enough that the CF pressure plate is not balanced correctly, their tech guy was full of BS and wouldn't own up to the fact that the pressure plate could be out of balance.

He first offered my brother some info about a couple of the bolts holding the PP on were bigger and went in specific holes to make the PP centered properly. That was BS and I called later in the day and he said we probably had the PP bolted into a wrong set of holes and we should take it apart and turn the PP to the next set of holes and keep doing that until it would be in balance. That was even more BS. Since the tech didn't know **** about clutches or how they install we decided to just get a new clutch and see if that solved the vibration which it did. Thanks Bill for confirming what we suspected.

Lots of mixed reviews about CF on the internet and there is no reason to buy something that you know you might have problems with and the tech people BS about the problems with their product. I am only describing what our experience with CF was.
 
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