Dual Mass Flywheel
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
that's getting touchy. If you abuse them, maybe 50k miles... if your careful, 120k miles.
There is a test. With the flywheel on the motor, put a bolt into a pressure plate hole and tighten. Once bottomed, then torque it. If the deflection is over 1", it's toast. Before that, use your best judgement.
If you decide to replace, I would suggest using a factory GM F-Body unit, versus, a fancy aluminum. The aluminum units are just too damned light. The fbody FW needs to be cut down .090 so it will fit right.
There is a test. With the flywheel on the motor, put a bolt into a pressure plate hole and tighten. Once bottomed, then torque it. If the deflection is over 1", it's toast. Before that, use your best judgement.
If you decide to replace, I would suggest using a factory GM F-Body unit, versus, a fancy aluminum. The aluminum units are just too damned light. The fbody FW needs to be cut down .090 so it will fit right.
Burning Brakes
Joined: Jan 2002
Posts: 1,228
Likes: 1
From: Dallas Texas
Originally Posted by bogus
The aluminum units are just too damned light.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
that might help.
But I stand by my statement.
Arisa installed a stage III clutch with a Fidenza SMF. I drove that thing last summer... It's nice, don't get me wrong, but lauching it in a parking lot requires a deft touch, and I had to slip the hell out of it just to keep from stalling. Mr Mojo drove it, too, and he stalled it TWICE inside of 10' before he got the hang of it.
I have a Fidenza, and it just seems too light to me. I don't get any sort of flywheel effect, which is needed on the street.
10lbs more would resolve the lack of mass without over burdening the engine.
Oh, the weight of the DM, ~40lbs, is a nominal weight. I have read where some are 36 and others are 42. It's because the DM is used as the engines external balancer, hense, one engine can be more out of balance then another.
But I stand by my statement.
Arisa installed a stage III clutch with a Fidenza SMF. I drove that thing last summer... It's nice, don't get me wrong, but lauching it in a parking lot requires a deft touch, and I had to slip the hell out of it just to keep from stalling. Mr Mojo drove it, too, and he stalled it TWICE inside of 10' before he got the hang of it.
I have a Fidenza, and it just seems too light to me. I don't get any sort of flywheel effect, which is needed on the street.
10lbs more would resolve the lack of mass without over burdening the engine.
Oh, the weight of the DM, ~40lbs, is a nominal weight. I have read where some are 36 and others are 42. It's because the DM is used as the engines external balancer, hense, one engine can be more out of balance then another.
Melting Slicks
Joined: Apr 2000
Posts: 3,490
Likes: 2
From: Oviedo FL
Originally Posted by mothersworry
How long does the typical dual mass last? I am building a 396 and need opinions to replace the dual mass. The dual mass had 79,000 when pulled.
This is an excellent clutch and can handle pretty much what you throw at it. The downside is there is very little slip in it and it takes a while to get used to launching it.
Mike
Racer
Joined: Apr 2002
Posts: 342
Likes: 0
From: new orleans La
I have a Fidenza and spec II setup on my LT4 along with 4.10 gears and it does take some getting used too. The engagement is much sharper than the stock setup. I usually need about 2k rpms to get going from a dead stop in first gear. Since my car is basically a weekend cruiser I prefer the stock setup.
Burning Brakes
Joined: Jan 2002
Posts: 1,228
Likes: 1
From: Dallas Texas
Originally Posted by bogus
I have read where some are 36 and others are 42.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Originally Posted by ninetyfivevette
I weighed mine on a bathroom scale and it was 36 on the head. My street twin assembled with flywheel, pressure plate and clutches weighed in at 36lb!
remember, add the clutch weight to the flywheel of the DM, I suspect that means the entire clutch assembly is about 60lbs!!!!!
Now, that's just too heavy... but the steel would weight about 46lbs, total.
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Drifting
Joined: May 2001
Posts: 1,295
Likes: 2
From: Surprise Arizona
I had my clutch replaced this winter. Doing much research on this subject I decided to stay with the stock setup for one reason. I wanted to retain the smooth start ability of the heavy DM flywheel. Reving the engine to get going from a start did not appeal to me. The LT4 will start to pull off from a stop easily without having to raise the RPM's more than normal.
As far as how long it lasts mine was toast with only 20k on it. The previous owner rode the clutch. There was a big difference in the amount of play the old DM had compared to the brand new one. I think the heat from slipping the clutch took it's toll on the DM.
As far as how long it lasts mine was toast with only 20k on it. The previous owner rode the clutch. There was a big difference in the amount of play the old DM had compared to the brand new one. I think the heat from slipping the clutch took it's toll on the DM.