Chance to buy a NOS DMF - Do it or wait? - CorvetteForum - Chevrolet Corvette Forum Discussion

Notices
C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Chance to buy a NOS DMF - Do it or wait?

Reply

 
 
 
Old 04-16-2018, 01:08 PM
  #1  
9T3VETTE
CF Senior Member
Thread Starter
 
9T3VETTE's Avatar
 
Member Since: May 2007
Location: Motor City
Posts: 1,092
Thanked 71 Times in 55 Posts
Default Chance to buy a NOS DMF - Do it or wait?

Ok, so i've come across the chance to purchase a NOS clutch disk and dual mass flywheel. Supposedly these are both brand new parts, never used.

Here's the dilemma, my car doesn't NEED a clutch right now. However it does have 95k on the stock clutch so at some point it will need to be replaced.

Do i go for it and buy the NOS clutch disk and DMF? Or wait until the clutch fails and most likely replace it with an aftermarket disk and heavy SMF?

Looking for some input from others who have been though the clutch replacement drama
9T3VETTE is offline  
Reply With Quote
Old 04-16-2018, 01:16 PM
  #2  
1984Z51auto
CF Senior Member
 
1984Z51auto's Avatar
 
Member Since: Jan 2003
Location: Denver Colorado
Posts: 702
Thanked 38 Times in 33 Posts
Default

While it is an opportunity to get a difficult part, is it a good price? All you are trading off the dual mass for is a little more noise... a good exhaust and turning up the radio will fix that. I'd only buy if the price is right.
1984Z51auto is offline  
Reply With Quote
Old 04-16-2018, 02:38 PM
  #3  
dizwiz24
CF Senior Member
 
Member Since: Sep 2001
Location: NEwhere Ohio
Posts: 9,628
Thanked 54 Times in 53 Posts
Default

You know already what id do.

get rid of the factory dual mass and put in a ligjtweight 12 lb fidanza flywheel

use a sprung hub clutch and thicker trans countershaft shim to mitigate 95 % of the noise that the dual mass absorbs.

enjoy the improved performance from dropping 25 lbs of rotating inertia
dizwiz24 is offline  
Reply With Quote
Old 04-16-2018, 05:28 PM
  #4  
DGXR
CF Senior Member
 
DGXR's Avatar
 
Member Since: May 2013
Location: Sacramento California
Posts: 1,736
Thanked 140 Times in 132 Posts
Default

DMF are in demand, especially NOS. So even if I didn't need it, I would also buy it... unless the price is crazy.
DGXR is online now  
Reply With Quote
The Following User Says Thank You to DGXR For This Useful Post:
BV85 (04-16-2018)
Old 04-17-2018, 06:35 AM
  #5  
jpipx
CF Senior Member
 
jpipx's Avatar
 
Member Since: Aug 2016
Location: Putnam Valley NY
Posts: 169
Thanked 25 Times in 21 Posts
Default

Originally Posted by 9T3VETTE View Post
Ok, so i've come across the chance to purchase a NOS clutch disk and dual mass flywheel. Supposedly these are both brand new parts, never used.

Here's the dilemma, my car doesn't NEED a clutch right now. However it does have 95k on the stock clutch so at some point it will need to be replaced.

Do i go for it and buy the NOS clutch disk and DMF? Or wait until the clutch fails and most likely replace it with an aftermarket disk and heavy SMF?

Looking for some input from others who have been though the clutch replacement drama
Let me know if you're not going to buy it, I may be interested!

Last edited by jpipx; 04-17-2018 at 06:36 AM.
jpipx is offline  
Reply With Quote
Old 04-17-2018, 09:26 AM
  #6  
QCVette
CF Senior Member
 
QCVette's Avatar
 
Member Since: Jun 2009
Location: Mclean IL
Posts: 5,488
Thanked 289 Times in 257 Posts
Default

If you are planning to keep a stock setup, then get it if it is a reasonable price.

If you don't care whether to keep your car stock or aftermarket, then get it if it is a reasonable price.

If you want to go to a single mass either standard weight or light weight, then it is only an investment. So get it if it is a good deal.

In my case I have had several dual mass setups and for me they work fine.

I had one SPEC single mass (the heavy one the same weight as stock) and I did not have any issues with the ZF noise. I just didn't notice any more noise. So I don't mind a single mass flywheel, and the lighter ones can add some acceleration improvement at the expense of ease of low speed engagement. So there may be some benefits to the single mass.

In my case I had a balance problem with the SPEC flywheel (off by 20 grams) and I replaced it with a dual mass.

Good luck with your choice.
QCVette is offline  
Reply With Quote
Old 04-17-2018, 10:26 AM
  #7  
9T3VETTE
CF Senior Member
Thread Starter
 
9T3VETTE's Avatar
 
Member Since: May 2007
Location: Motor City
Posts: 1,092
Thanked 71 Times in 55 Posts
Default

Thanks for the input everyone. Honestly, i'm not well versed on the clutch offerings for our cars other than the increase in gear noise with a light flywheel (which can be mitigated as brought up by diz) and the fact DMF's are hard to come by.
The only reason i'd be purchasing is to have options when the time inevitably comes.

What's a reasonable price for new DMF?

The kit being offered is an NOS bellhousing + NOS disk + NOS DMF. Is there value in getting all 3 pieces? Or is the DMF the only valuable piece.

EDIT:
One more thing....

Is there a difference between 91-96 disks and DMF or are they all the same design?

Last edited by 9T3VETTE; 04-17-2018 at 10:29 AM.
9T3VETTE is offline  
Reply With Quote
Old 04-17-2018, 10:31 AM
  #8  
WVZR-1
CF Senior Member
 
Member Since: Sep 2003
Location: Charles Town WV
Posts: 17,031
Thanked 923 Times in 886 Posts
Default

Originally Posted by 9T3VETTE View Post
Thanks for the input everyone. Honestly, i'm not well versed on the clutch offerings for our cars other than the increase in gear noise with a light flywheel (which can be mitigated as brought up by diz) and the fact DMF's are hard to come by.
The only reason i'd be purchasing is to have options when the time inevitably comes.

What's a reasonable price for new DMF?

The kit being offered is an NOS bellhousing + NOS disk + NOS DMF. Is there value in getting all 3 pieces? Or is the DMF the only valuable piece.
Were you supplied part #'s for what was offered to you? Snapshots and casting #'s?

There would be 2 DMF - 1 for L98 - LT1/4 and the 2d for an LT5. Disc would be same for all regardless of engine. Clutch housing there would be 3 '89 & '90 L98, '91+ L98 - LT1/4 and a 3d for the LT5

Last edited by WVZR-1; 04-17-2018 at 10:40 AM.
WVZR-1 is offline  
Reply With Quote
Old 04-17-2018, 10:57 AM
  #9  
9T3VETTE
CF Senior Member
Thread Starter
 
9T3VETTE's Avatar
 
Member Since: May 2007
Location: Motor City
Posts: 1,092
Thanked 71 Times in 55 Posts
Default

Originally Posted by WVZR-1 View Post
Were you supplied part #'s for what was offered to you? Snapshots and casting #'s?

There would be 2 DMF - 1 for L98 - LT1/4 and the 2d for an LT5. Disc would be same for all regardless of engine. Clutch housing there would be 3 '89 & '90 L98, '91+ L98 - LT1/4 and a 3d for the LT5
Thanks.

Bell housing -> 10126448
DMF -> 1 204 074 00 (also shows FSG4 but I think that is a date code)
9T3VETTE is offline  
Reply With Quote
Old 04-17-2018, 11:42 AM
  #10  
WVZR-1
CF Senior Member
 
Member Since: Sep 2003
Location: Charles Town WV
Posts: 17,031
Thanked 923 Times in 886 Posts
Default

Originally Posted by 9T3VETTE View Post
Thanks.

Bell housing -> 10126448
DMF -> 1 204 074 00 (also shows FSG4 but I think that is a date code)
Housing is '91+ LT1/4

L98 - LT1/4 DMF I'm not familiar with but I'd think GOOGLE would be a friend.
WVZR-1 is offline  
Reply With Quote
The Following User Says Thank You to WVZR-1 For This Useful Post:
9T3VETTE (04-17-2018)
Old 04-17-2018, 07:16 PM
  #11  
QCVette
CF Senior Member
 
QCVette's Avatar
 
Member Since: Jun 2009
Location: Mclean IL
Posts: 5,488
Thanked 289 Times in 257 Posts
Default

Also be aware that on the two L98/LT1/LT4 bellhousings they are different. The early are aluminum and the later are magnesium. The magnesium has the word magnesium cast on the surface of the belhousing to make it easy to spot which one. The magnesium one needs to have formed or stamped shims between the housing and the block. If you do not have them the position of the bellhousing will be too close to the block and may cause some problems Like the clutch fork being too close to the pressure plate. So if magnesium, make sure to get the shims with it. Either bellhousing can work. The aluminum one without shims interchanges with the magnesium with shims.

On the dual mass flywheel, the LT5 has one more bolt hole than the L98/LT1/LT4 one does, so it is easy to check. The L98/LT1/LT4 flywheels interchange. I used a '90 (L98) on my '96 (LT4). I think there was a running change on them that may have upgraded the seal so that the later ones are better, but I don't remember the specifics of what year they changed (although my guess is about '91 or '92).

Good luck.

Last edited by QCVette; 04-17-2018 at 07:19 PM.
QCVette is offline  
Reply With Quote
Old 04-17-2018, 09:29 PM
  #12  
9T3VETTE
CF Senior Member
Thread Starter
 
9T3VETTE's Avatar
 
Member Since: May 2007
Location: Motor City
Posts: 1,092
Thanked 71 Times in 55 Posts
Default

^ Great information really appreciate that QC. Never knew about the shims. The housing does indeed have magnesium stamped in it so it must be a later model piece. Here are some pics of the parts for sale.





9T3VETTE is offline  
Reply With Quote
Old 04-20-2018, 08:09 PM
  #13  
Ken Linder
Junior Member
 
Member Since: Jun 2017
Posts: 10
Thanks: 0
Thanked 4 Times in 3 Posts
Default

If you decide to go the DMF route, I'm providing information regarding balancing. This is from the manufacturer (LuK). The balance weights removed from my flywheel are 3 gram and 2 gram sizes. I made new weights from 0.248 dia. carbon steel rod. 0.50" length = 3.0 grams. The original weights had raised notches on the side for a friction fit. New and original weights (with piece of rod) are in the picture. I suppose you could secure new weights with Loctite or deform the weight for a friction fit. For curiosity, I used a website centrifugal force calculator to find that there is 16.5 pounds of centrifugal force on the 3 gram weight at 4000 RPM. These fine balance weights are important.


Ken Linder is offline  
Reply With Quote
The Following 2 Users Say Thank You to Ken Linder For This Useful Post:
9T3VETTE (05-09-2018), GRKLGHTNG (05-05-2018)
 
 
 


Thread Tools
Search this Thread
Sponsored Ads
Vendor Directory

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: