Why do the flywheel conversion?
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Junior User
Joined: Jan 2009
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Why do the flywheel conversion?
I'm still new to the diesel crowed and I've been reading a lot here and a few people mention upgrading the flywheel. What's the benefit to this mod? What exactly needs changed to do this? I have a 7.3 turbo IDI with the ZF 5speed.
Posting Guru
Joined: Jan 2001
Posts: 1,101
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From: Poway, CA
Dual-mass flywheels (DMFs) are known to fail. They were intended to be a means to keep rollover noise and other transmission chatter to a minimum, but, as I understand it, the springs inside it fall apart. The solution is to replace the flywheel with a basic solid flywheel, much like you see in most other vehicles with standard transmissions.
Mike
Mike
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Joined: Jan 2001
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From: Poway, CA
It's my understanding that all manual transmission trucks came with a Dual Mass Flywheel from factory, so unless the truck in the yard had the conversion, probably not. Really, all that's involved is using a Solid/Single mass flywheel (SMF) when doing a clutch job (as opposed to the DMF). You'll know the difference at the parts store by the price. DMF is WAY more expensive, which is probably the other big reason people convert to SMF. Just know, there are some alleged drawbacks to the SMF, mainly a louder experience in the cab. Some also claim it shakes some stuff apart. Can't speak more to this since, knock on wood, I'm running on the original clutch.
Mike
Mike
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Joined: Jul 2012
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From: Centerville TN
I have driven a 99 f350 with the solid conversion. The clutch pedal is a whole lot easier to push in the 99 compared to mine, which still has the dual mass. I found the solid flywheel and the clutch kit on rock auto for right around 280$. That's without shipping.
Senior User
Joined: Mar 2013
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From: aouth east idaho
We will see how it works out but I just ordered the kit from orielly and it comes with everything you need and it was 470$ so we will see what happens and how it works. One thing I thought was cool with the kit is stock it has 11inch clutch but the kit upgrades you to a 12.
Post Fiend
Joined: Feb 2009
Posts: 8,005
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From: Ottawa, Ontario
I have 377k miles on my original clutch and DMF in my 1990 F250.
And yes my flywheel is worn, you hear it...
Anytime you shut down the truck, with the clutch engaged in neutral, you'll hear a loud KNOCK KNOCK knock.
That's the 2 halfs of the flywheel hitting each other cause the springs holding them together are tired.
If it completely breaks apart, it can crack open the bell housing from what someone on here has experienced.
And yes my flywheel is worn, you hear it...
Anytime you shut down the truck, with the clutch engaged in neutral, you'll hear a loud KNOCK KNOCK knock.
That's the 2 halfs of the flywheel hitting each other cause the springs holding them together are tired.
If it completely breaks apart, it can crack open the bell housing from what someone on here has experienced.
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i ain't rite
Joined: Mar 2005
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From: Marlboro Mental Hospital.
another sign a DMF is going south id it will feel like the clutch is slipping in higher gears.
on my 88, after about 45 minutes of driving the clutch would feel like it was slipping.
but shut it down for the night and it was good for another 45 minutes or so.
when i decided to dump the DMF it did a test.
got it hot, and let the clutch out in 5th gear. the truck sat there with the engine running in 5th.
the next morning before taking it apart, i burned the 37 inch tires in 1st and 2nd gears down the road.
when we took it apart, the little clutch disc in the flywheel fell out.
on my 88, after about 45 minutes of driving the clutch would feel like it was slipping.
but shut it down for the night and it was good for another 45 minutes or so.
when i decided to dump the DMF it did a test.
got it hot, and let the clutch out in 5th gear. the truck sat there with the engine running in 5th.
the next morning before taking it apart, i burned the 37 inch tires in 1st and 2nd gears down the road.
when we took it apart, the little clutch disc in the flywheel fell out.
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Joined: May 2010
Posts: 756
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From: central illinois
I did this conversion recently. Yes I do get gear rollover at low rpm but it goes away quickly. Mainly in 1stthe and reverse when idling down my drive. Clutch is easier to operate and has better response. I went with LUK clutch and flywheel as well as a new Fork. Glad I did as mine had some wear spots. I bought all my parts on Amazon and I think it cost around $350. Free shipping was good too.
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