flywheel replacement

[cop1270]

After hearing a rattle coming from, what I thought was in the emission system area of my 91 roadster, I took the car to a repair shop. The machanics called me about an hour later and gave me the sad news that the car had a bad fly wheel which needed to be replaced to the tune of sixteen hundred dollars ($1200.00 GM parts and $400.00 labor). I was also advised by them that I could possibly locate a shop that could install an after market fly wheel at a much lower cost but the after market parts would require expert type of balancing to make it right. Has anyone ever experiened anything like this. My Vette has only 32K miles.

 

[topless82vette]

if it's a 6 speed sounds about right, my friend had a new one put in his 1990 think his flywheel was 850 but the total clutch job was like 1500

 

[G Winter]

I purchased a dual mass flywheel and clutch setup from Carolina Clutch and Performance, Inc.: for $1050 including shipping.The clutch was just under $300 and the flywheel was just under $700
It was the same as OEM. came complete with weights for flywheel and alignment tool. This was last summer don't know about pricing since then.

Glenn

 

[So Bay Vetter]

Unless you really trust this guy, I'd get a second opinion from a Vette shop just to make sure you're not paying $1600 for $25 worth of emissions parts. If it is the flywheel, it's a good time to do the clutch as well since it will all be apart anyway.

 

[G Winter]

The rattle you heard may have been your gears clattering due to a worn dual mass flywheel.
If you replace the dual mass in your car with a replacement dual mass flywheel, balance should be no problem. The flywheel has 1/4 in holes all around. The old flywheel has weights in diff. locations to balance it. All you do is put the weights in the corresponding holes in the new flywheel.
Don't even think about replacing the flywheel without doing the clutch. The people at Carolina clutches told me the life of a clutch in a vette is tipicly worn by 60,000 miles.
They are good people there and will answer any questions you have.

Glenn

 

[cop1270]

Thankyou Glenn and the guys with the other input. After considering your advice and making other inquiries I decided to go with the original type GM flywheel. It was more expensive but it comes already balanced and ready to install. The clutch looked "new" according to the mechanics so it wasn't replaced. The car has only 32K miles but I've heard that they do go early sometime. I picked the car up today and it runs great with no more rattle. After I pay off my credit card I'll love the car again I'm sure.
Thanks again

 

[redvett]

Make sure your engine isn't misfiring it will cause the flywheel to make noise.

 

[So Bay Vetter]

Wow, throwing a flywheel at 32K ? Did the mech. have any idea what caused it?

 

[Hib Halverson]

Ok, there's some misconceptions, here, about how the dual mass works.

First, if the engine is missing, a dual mass flywheel in good condition will not rattle. But, the transmission will rattle.

Gear rattle from the ZF S6-40 six-speed, when the engine is idling, is the result of changes in engine speed caused by firing impulses. The engine fires four times per revolution. If you could very accurately measure engine speed, you'd find it fluctuates. A cylinder fires and the engine speeds up, but then slows before the next cyilnder fires. Then it speeds up and slows, until the next one fires and so forth and so on.

At idle, this fluctuation happens slow enough that it causes the main drive gear and the countershaft teeth to rattle against each other.

The dual mass flywheel damps some, but not all of that rattle. If the engine is missing, the fluctuations in engine speed are much greater and, thus, the rattle from the trans (in-spite of the dual-mass' damping) is louder.

When the dual mass flywheel fails, the damper weight may also begin to rattle and, because the dual mass is failing or has failed the gear rattle from the trans gets worse.

This problem is compounded in 89s, 90s, 91s and some 92s which have the earlier ZF unit having gears with teeth having less helix angle.

You can eliminate the expense and weight of the dual mass by going to a standard flywheel, typically an aluminum unit. This is a common performance upgrade, however, when you ditch the dual mass, you get an increase in gear rattle and also low rpm growl in first gear.

The best aluminum flywheels for replacement of dual mass flywheels are either the McLeod or the Fidanza. Those two, also, make the best clutches, IMO.

 

[cop1270]

Wow, throwing a flywheel at 32K ? Did the mech. have any idea what caused it?

No, he didn't have any idea why it went so early. He said the clutch and other components looked brand new though. Go figure.

 

[jerry rio]

dual mass flywheel

No, he didn't have any idea why it went so early. He said the clutch and other components looked brand new though. Go figure.

on a 1991 L98 6 speed
Have replaced the dual mass flywheel. with new clutch still have the same noise. sounds like rod knock.

only after it warms up.... any suggestions.
complete tune up.. no misfires....

can it be I received a bad new flywheel????

 

[G Winter]

I would check the front damper. Might be coming lose.

Glenn

 

[jerry rio]

I would check the front damper. Might be coming lose.

Glenn

Thanks for responding, I will check the damper , but still think it may be the flywheel. just picking brains before taking the trans back down. all the symptoms are just as others have had knock starts when hot not cold. shifts fine, sounds coming from the bell housing. If you should think of any thing else let me know..

Jerry

 

[jerry rio]

Heyhib halverson , are you there::????

 

[Hib Halverson]

Here I am.

Did you solve your noise problem?

 

[jerry rio]

not yet, still think it's a bad flywheel, but the chevy dealer now is looking at it to my dismay, The want to take the new transmission oil out that they sold to me the other day for 12.oo per quart and advise to put 5w 3o motor oil in the tranny.....

man,,,,this is crazy..... but some I've heard do it...