Balancing flywheel and clutch assembly together?

[JGraft]

Has anyone heard of this? I recently purchased a Hays clutch kit along with a new flywheel and in the "Dos & Dont's Problems" paperwork from Hays
states "Hays recommends balancing clutch/flywheel as assembly before installation." The paperwork also states "Balance with crank if possible." Paperwork identifies this next to a problem of "Vibration at high RPM."

Just wondering if this balancing is really necessary or not and what other CRG experts might suggest. I do not intend to race the car, or rev the engine to extreme RPMs, it will only be an occasional street driver. I also don't want to put everything together to find out it needs to be disassembled to correct a clutch vibration problem.

[MO]

It would be good to do, but should be okay for a street car if you don't. You'd definitely want to for a high performance build.

[GMAD_Van Nuys]

I read the instructions from Hayes and their suggestion about balancing the flywheel & assembly was listed if you had a vibration problem at high rpm:

https://documents.holley.com/199r11791.pdf

These instructions also are not specific to the type of vehicle, so you may want to call the manufacturer if you have questions.

[NAPA68]

I'm a bid advocate of it, as I HATE doing things twice. You'd be surprised how far off a pressure plate can be.

Tim

[rszmjt]

I'm a bid advocate of it, as I HATE doing things twice. You'd be surprised how far off a pressure plate can be.

Tim

Totally agree, I had a well known brand name pressure plate that was off 23 grams, they all seem to be off a bit but not usually that much. We all ways zero balance the flywheel, then bolt on pressure plate and make any changes just to the pressure plate, that way everything is zero neutral balance.

[Brew14u]

As a data point, I didn’t balance the clutch/flywheel assembly before installation and have not had vibration issues.  I recently put a Luk RepSet 04-021 and a resurfaced donor GM 3791021 flywheel in my unmodified 1969 Z28.  I installed the clutch kit straight from the box and only had the donor flywheel resurfaced.  I have been restrained so far during break in and have only driven it about 4 times, 10 miles each, maximum of about 4,500 rpms.  No vibrations so far and much improved over the worn out clutch that ultimately suffered a catastrophic failure.

[jeff68]

We all ways zero balance the flywheel, then bolt on pressure plate and make any changes just to the pressure plate, that way everything is zero neutral balance.

This is exactly what was done to my flywheel / pressure plate at the recommendation of my engine builder.

[lynnbilodeau]

"We all ways zero balance the flywheel, then bolt on pressure plate and make any changes just to the pressure plate, that way everything is zero neutral balance."

Perzactly!

This is the ONLY way that makes any sense.