BillWelter

What type of flywheel and clutch-plate is used for this? I've only found aluminum flywheels, probably because a steel one that provides the correct spacing would be too heavy. Any advice? Thanks.

TOO_HOTTVETTE

I have not seen an aftermarket dual mass flywheel replacement for the ZF 6 speed. The OEM dual mass flywheel is very expensive $700 plus. The aluminum flywheels are much lighter than the factory dual mass, and are most likley a single mass type. They are mostly used for performance gains. Be advised that if you replace the flywheel with something other than the dual mass, you will get the dreaded gear rattle from your gearbox. Though it is not harmful to your tranny it is noisey and irritates some folks. I have a single mass flywheel and the noise bugs me but my exhaust and engine work mask the noise pretty well. I may consider going back to the factory set up because of the noise. Hope this helps

BillWelter

Yup, I'm scared that the dual-mass parts will separate, leaving me stranded. What kind of single-mass flywheel did you use, and did you also change to a sprung clutch disc? Thanks.

pablocruise

It depends on how your engine is balanced.
Some engines are externally balanced and need flywheels and harmonic dampers with weight on them in certain amounts and locations.
For dual mass, either you get a new dual mass observing the balance issue or
you switch to a single mass FW. I am using a steel camaro FW. Neutral balanced since my motor in it's current incarnation is internally neutral balanced.
The dual mass limits your clutch disc choices since you cannot use a "sprung hub" disc. This is no problem if staying within stock torque output levels. However, if torque is way more than stock or if using stick slicks at the strip, you will want to find a tougher clutch disc.

TOO_HOTTVETTE

:iagree:
The factory dual mass flywhell has weights that they used to balance to your motor from the factory. As stated, for guys with the major mods, the sigle mass performance gains out weigh the noise factor. I have an LT1/LT4 conversion with the HOTCAM, 52mm TB, custom chip and some exhaust work. I'm thinking that the factory dual mass flywheel would be enough to handle my particular mods. (the ZR1 used the same dual mass set up) And I should be in the same ballpark power wise.

BillWelter

Thanks Paul. I'm building the motor, and will be internally balancing it with the flywheel. The LT1 doesn't have a real harmonic balancer, so that's no problem. You have a ZF and are using a Camaro FW? So you're using a sprung disc, Camaro, too? I was considering this setup. Does the stock pressure plate bolt to the Camaro FW, and does the clutch slave cylinder work properly? I was worried about the spacing between the crank and the FW face not being the same, and changing the throwout bearing linkage geometry. Thanks again.

pablocruise

Here are some examples

note the camaro single mass on left. It's center is recessed.
Here is what I had to do when I wanted to use a single mass nuetral balanced camaro FW on an externally balanced 89 L98

Since then, I have rebuilt my L98 so that it is internally neutral balanced and I reomved that welded on mass.
Here is some SPEC III carbon fiber clutch discs. I recommend you stay away from SPEC!! note the sprung hubs

and here is a McLeod kevlar unit


so far so good on the Mc. It's given me my best 60 ft. times.
The pressure plate is the same VALEO unit we all use. Only Valeo makes our PP. I had minor clearance issues with the fork but that's all. Some minor grinding on the fork took care of that. Other forum members have had major problems.


[Modified by 89 Paul in Cal, 7:03 PM 11/2/2003]

BillWelter

Paul, thanks!! you just happen to have these pictures handy? So the Corvette pressure plate bolts to the Camaro FW OK, and you're using a Camaro-style disc, so that will work. And the throwout mechanism works? This sounds too goo to be true, thanks again.

pablocruise

yes the valeo PP bolts to the camaro FW.
I am using the McLeod kevlar. I called Mc ans said I have XXX amount of hP and TQ, and am using slicks at the track. I used a spec III CF and it held, but it did not last. Do you have anything I can use? They said try this one. So far so good.
This topic comes up alot and the pics I have kept to help out when I can.
The throw out bearing,
there are two available. This because the O.D. of the ZF6 input shaft changed in 92 I think. So just need to figure out what tranny have, and measure if possible the input shaft OD and or the ID of the TO bearing.
The camaro steel FW needs to be machined down from it's stock thickness. I think .090


[Modified by 89 Paul in Cal, 3:43 PM 11/4/2003]

superlund

Hey Bill, spotted your question/post over on the Silver State message board, but I don't post over there. FWIW I ran a Fidanza aluminum SM flywheel in the 130 class at the 03 Pony Express ORR, no problems.
Forum member No Go has a page with all of the part numbers required for the steel camaro SM flywheel conversion here; http://temp.corvetteforum.net/c4/nog...nversion.shtml

BillWelter

Hi Superlund, thanks for the info. I suppose the Camaro flywheel needs to be surfaced to make the Corvette clutch linkage work properly, eh? I ordered a flywhel already, I'll make sure I get the right one. Just curious, how much noise have you noticed after the conversion? Thanks.

superlund

The ZF Trans is very loud W/O the dual mass... The aluminum SM flywheels are worse (louder) than the nodular iron/steel SM flywheels, as aluminum has very little vibration damping compared to nodular iron.
It's all personal preference, but I would never go back to a dual mass setup.

BTW as mentioned above, there were (2) release bearing collar diameters on the ZF Trans used in C4's make sure you measure the collar & get the correct release bearing.

Strick

Hi Bill, Is your Vette for daily driving? If so, I'd stay with the dual mass, unless you're going to have more HP than a ZR1. It seems that somewhere along the line a guy has to make up his mind as to if he wants a daily driver or a full race car. If you are headed to the full race mode, go ahead and beef up the clutch and the noise of the ZF won't bother you as the rest of the car will drown out the clatter. I'm going through the decissions of clutch replacement as mine got oil on it and slips. If I want my wife to take a ride with me, it's the dual mass stock replacement. But there's this urge in me that says, "GIVE ME MORE SPEED, SCOTTY"

BillWelter

Thanks all! I got a Camaro SM flywheel today, and put a used Corvette clutch plate and pressure plate on it, and by golly, it fits! I measured the thickness on the SM flywheel (between the clutch face and crank face), and it's going to need about .090" inch machined off, just like Superlund and TMCArthurs said it would! I'm going to use my stock '94 Corvette PP and TO bearing, they were replaced not too long ago. The reason I'm worried about this whole thing is that I'm building up a 383 for it, with lots of go-fast goodies. I'm running Silver State Classic again next year, and will have a bit more power. I just don't want anything weird to happen and leave me stranded. Thanks all for the help!!