Resurfacing the 1996 LT4 flywheel
Thread Starter
Drifting
Joined: Oct 2004
Posts: 1,957
Likes: 6
From: The Woodlands TX TX
Resurfacing the 1996 LT4 flywheel
I just had a new clutch installed and afterwards the whole drivetrain seemed out of balance at 4500 RPM. The dealer is putting in a new flywheel because they resurfaced the original and think it is now the culprit.
I need to know whether or not they ruined the original by resurfacing it. It is a 1996 LT4 engine.
I heard it is a "dual mass" flywheel and should not be machined. Is that true?
Where can I go for any real documentation on this servicing? I want the "no ****" GM manual for a new clutch install. I have a Chilton manual and it is missing details about the flywheel.
I want them to pay the 800 Bucks for the new part, because I believe they shouldn't have messed with the original.
Any real help is appreciated.
Thanks,
Ryan
I need to know whether or not they ruined the original by resurfacing it. It is a 1996 LT4 engine.
I heard it is a "dual mass" flywheel and should not be machined. Is that true?
Where can I go for any real documentation on this servicing? I want the "no ****" GM manual for a new clutch install. I have a Chilton manual and it is missing details about the flywheel.
I want them to pay the 800 Bucks for the new part, because I believe they shouldn't have messed with the original.
Any real help is appreciated.
Thanks,
Ryan
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
there are a number of issues... one being the membrain that makes up the connection between the masses; the other - space.
The space considerations are huge... once the flywheel has been cut, it is now thinner. as hard as it is to believe, that little bit will throw the geometry off enough to cause problems.
Also as important, mileage... a DM will not last much past 120k miles. And that's it.
These flywheels should NEVER be resurfaced.
The space considerations are huge... once the flywheel has been cut, it is now thinner. as hard as it is to believe, that little bit will throw the geometry off enough to cause problems.
Also as important, mileage... a DM will not last much past 120k miles. And that's it.
These flywheels should NEVER be resurfaced.
Safety Car
Joined: Apr 2004
Posts: 4,532
Likes: 7
From: Lahaina Hi
That is like installing used break pads with new rotors WTF!
The flywheel is one of 3 of the most inportant pieces that allow your car to turn the rpm and speed it does.
You cut the flywheel and it lightens it up ,less weight less torque.Not balanced and a real bad vibration(how is your teeth)
Yes the flywheel has to be replaced when the clutch is renewed or you will burn up the new clutch disc.
The flywheel is one of 3 of the most inportant pieces that allow your car to turn the rpm and speed it does.
You cut the flywheel and it lightens it up ,less weight less torque.Not balanced and a real bad vibration(how is your teeth)
Yes the flywheel has to be replaced when the clutch is renewed or you will burn up the new clutch disc.
Melting Slicks
Joined: Apr 2003
Posts: 2,150
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From: NS
As others have said, the GM service manual says to never re-surface the DM flywheel.
Make sure your shop knows that when they replace the flywheel they need to use the same balancing weights plugged into the holes on the back side. Look at the old flywheel and press balancing weights in the same holes on the new one.
Make sure your shop knows that when they replace the flywheel they need to use the same balancing weights plugged into the holes on the back side. Look at the old flywheel and press balancing weights in the same holes on the new one.
Race Director
Joined: Feb 2003
Posts: 11,672
Likes: 20
From: Lake Wylie SC
Originally Posted by Atok
As others have said, the GM service manual says to never re-surface the DM flywheel.
Make sure your shop knows that when they replace the flywheel they need to use the same balancing weights plugged into the holes on the back side. Look at the old flywheel and press balancing weights in the same holes on the new one.
Make sure your shop knows that when they replace the flywheel they need to use the same balancing weights plugged into the holes on the back side. Look at the old flywheel and press balancing weights in the same holes on the new one.
Team Owner
Joined: Sep 2002
Posts: 22,209
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From: OBAMA IS HITLER
Melting Slicks
Joined: Feb 2001
Posts: 2,512
Likes: 5
From: ZR1 Gathering '04, '05 Northlake Texas
I just had my clutch replaced on my ZR-1 and they resurfaced the fllywheel. I do not notice any problems so far. But now you all got me worried that I may start having some problems. The trans guy told me they would use shims to make up for the differance in the resurfing. He sounded like he knew what he was doing. They sent the flywheel out somewhere to have it resurfaced. Now I don't know what to think...
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Team Owner
Joined: Aug 2000
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From: San Pedro CA
Originally Posted by bradvette
Warning: The resurfacing process performed by Dualmass Inc. is not recommended by the original equipment manufacturer. By using DualMass Inc. services and not buying a new flywheel from the original equipment manufacturer the customer assumes full responsibility for their own actions. DualMass Inc. WILL NOT be held responsible for any damages to persons or property up to and including death.
I would not do it.
Think of it this way... the DM acts as the sprung hub on a conventional clutch. If the clutch is blown at 45k miles due to racing, what is the condition of the flywheel? If it's just worn after 110k miles? What's the condition of they flywheel?
I would not reuse the DM... It's expensive, but so is you car - if the 2 masses decided to come unglued at 4500 RPM, I don't know what would hold it all together? That's a lot of weight coming apart... yuck.
Now... if someone could properly remanufacture a DM, now we are talking! I would love to see that! As it stands, they become huge boat anchors... take them apart, replace the membrain, add metal to the surface and machine accordingly.
Melting Slicks
Joined: Feb 2001
Posts: 2,512
Likes: 5
From: ZR1 Gathering '04, '05 Northlake Texas
Originally Posted by Mikez40
I just had my clutch replaced on my ZR-1 and they resurfaced the fllywheel. I do not notice any problems so far. But now you all got me worried that I may start having some problems. The trans guy told me they would use shims to make up for the differance in the resurfing. He sounded like he knew what he was doing. They sent the flywheel out somewhere to have it resurfaced. Now I don't know what to think...
Well after reading all this, I call my trans guy who replaced my clutch and he said YOU DO NOT RESURFACE the flywheel.. I just misunderstood what he told me on mine. They did not Machine it, all thy did was buff off all the dirt to make it look new. So now I feel much better..
Team Owner
Joined: Sep 2002
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From: OBAMA IS HITLER
bogus, yeah i agree that caveat at the dualmassinc. site is really something.
one thing though.....hasn't the one big fear regarding resurfacing these been the use of cutting fluids and the probable damage to the membrane --- these guys claim they don't use any, so there's no damage.
one thing though.....hasn't the one big fear regarding resurfacing these been the use of cutting fluids and the probable damage to the membrane --- these guys claim they don't use any, so there's no damage.
Race Director
Joined: Dec 2002
Posts: 13,348
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Okay, anyone have a DM flywheel that "can't be resurfaced" which they will give to me?
I'll pay shipping... PM me.
I'm going to figure out a way to salvage these things and save the Corvette Forum members some significant cash.
Larry
code5coupe
I'll pay shipping... PM me.
I'm going to figure out a way to salvage these things and save the Corvette Forum members some significant cash.
Larry
code5coupe
Thread Starter
Drifting
Joined: Oct 2004
Posts: 1,957
Likes: 6
From: The Woodlands TX TX
Well, the new flywheel is in and it runs great. I have no idea if they used the original weights or not. I guess we will find out soon enough. The vibration is gone now anyway, so I guess whatever they did worked. The bad thing was the price. 2100 total for a new clutch and flywheel. I would have felt better about it had they told me that up front.
Race Director
Joined: Feb 2003
Posts: 11,672
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From: Lake Wylie SC
The only problem I see in rebuilding the dual mass is the tooling up and cost of your over head. Remember, there aren't that many LT1 and LT4s out there, relatively speaking, and they are getting old.
The inspection of the dual mass flywheel is outlined in the Helm's Service manual. It tells of the rotational difference between the two masses. If it passes this, just rough it up with a little scotch brite and re-use.
The inspection of the dual mass flywheel is outlined in the Helm's Service manual. It tells of the rotational difference between the two masses. If it passes this, just rough it up with a little scotch brite and re-use.