Funrunner99

I have a '90 Z51 Coupe with the 6 speed stick. Clutch bearing is making a little noise so a new clutch is probably in my near future. The car has aftermarket cat-back exhaust and that's about it, mostly stock. What would everyone recommend for fairly aggresive street driving in the hills and maybe a little drag racing action? Should I change the flywheel at the same time? Aluminum flywheel or steel? I have a twin turbo'd small block ford with an aluminum flywheel that I really like.

Thanks for the help!

John

PLRX

You should be good with a stock replacement.

Here you go

http://www.dial-a-clutch.com/category_s/28919.htm

inedajob

Do not replace your Dual Mass flywheel!
Do not replace your Dual Mass flywheel!
Do not replace your Dual Mass flywheel!
Do not replace your Dual Mass flywheel!

Unless it is bad keep your dual mass or you'll have engine vibrations @ 3,000 rpm and up, which the dual mass buffers out.
Check this out!
http://www.corvetteactioncenter.com/...l-problem.html

Cavi

that link was interesting reading, however some of it was a bit hard to swallow. I understand balancing a flywheel, but one of the posters stated that if you bought a new flywheel you had to have it balanced exactly like the one it was replacing or it would harm the engine. If that were the case GM would not just sell you the part without the reccomendation of doing a balance. Second, if that was the case every time you removed the flywheel you would have to reinstall in exactly the same orientation.
The balancing should be done so as to make sure the flywheel itself is not introcucing any vibrations into the mix.
Has anyone here ran a single mass flywheel or an aftermarket dual mass flywheel? Not that I am planning on doing that I am just curious as to the results.

inedajob

http://forums.corvetteforum.com/c4-t...light=inedajob

If anyone knows were I can buy a duel mass (new) I'd replace my billet FW NOW!!

Funrunner99

I read the thread on the link. Sounds like some have switched to standard flywheels with no trouble, seems like aluminum is the preference. Another said that the dual mass needs to be replaced by 90K, my car is at 93K. All the flywheels I have looked at have said they were neutral balanced. I thought GM did the balancing internally or with the front damper? I have never heard of a dual mass flywheel. Sorry, this is one of the only GM products I have ever owned, have always been a Ford/Mopar guy. Anyhow I have seen kits with and without flywheels included. I just want to get the right parts without breaking the bank (just went through a divorce, LOL). My '68 Mustang is a 28 oz. balanced motor which is a pain in the butt in my opinion. I have a Hays bullet flywheel on it with a TKO 600, really like the light flywheel. If I do replace the flywheel I would be inclined to go aluminum again. I just want to get it right the first time and don't want the old dual mass to go away on me after I do all the work if I kept it. Thanks in advance for all of the advice! I am getting pretty attached to this Corvette thing!

sailorsteve

I do not believe there is such an animal as an aftermarket DM flywheel. Not likely either- expensive to tool up for and make, and limited market. Best bet if you need one is to find a used one that has been removed.

The dual mass flywheel was meant to counteract vibration in the ZF 6-speed trans, not the engine. GM has made smallblock's since 1955 and these engines have never needed a dual-mass flywheel. If you change to a single mass (conventional) wheel, the only drawback is trans rattle and vibration that are objectionable to some, but not all.

esham

Did you end up using the Spec Clutch that you mentioned above? If so, are you still getting a lot of transmission rattle?

inedajob

Wish it were so ........check this, as of 86 Chevy small block cranks were modified to allow a one piece rear seal this changed the crank flywheel and thus the duel mass to make up for the internal balancing no longer supplied by the earlier cranks.

scroll to page 2 of this site.

http://www.docstoc.com/docs/22439849...V8-CRANKSHAFTS

inedajob

Yes, that is the FW I put in and I do still have ENGINE vibration. I can be parked with the clutch in which disconnects the trans and rev to about 3,000 rpm when the shuttering begins to be noticeable.

Check out page two (2) of this site...

http://www.docstoc.com/docs/22439849...V8-CRANKSHAFTS

sailorsteve

I read this link- I still think you're mistaken about the reason for the DM flywheel, since it wasn't used until the ZF 6-speed was introduced, in 1990. The torsional movement mentioned is not specific to the sbc, which is why most, if not all, engines have the torsional damper on the front of the crank.

sailorsteve

When the clutch is in, the input shaft is freed from the torque of the engine, but it doesn't fully stop turning if the trans is in neutral. This is why, in a manual trans without a synchro in reverse, you can feel the gears engaging. Note that the ZF DOES has a reverse synchro.

Funrunner99

[QUOTE=inedajob;1579478436]Yes, that is the FW I put in and I do still have ENGINE vibration. I can be parked with the clutch in which disconnects the trans and rev to about 3,000 rpm when the shuttering begins to be noticeable.QUOTE]

inedajob, you still have the vibration "after" you installed the counterweights?

inedajob

I did not install weights. This would have required multiple tries, meaning mounting the weights in the most likely position and if this didn't work remove and try again until best results are obtained. this seemed archaic to say the least so I have been trying to find another solution. My 95 has 98,000 on the clock so I've been toying with Erod when she goes.

Blitzkrieg

Alan777

I've got a 91' with a ZF-6 and a Spec Stage 1 clutch and Single mass flywheel (with the extra mass option).

The car drives fine once at speed, but

1 when pulling out the car shudders/shakes, and
2 when i let the clutch out in neutral it sounds like rocks in a can.

I get NO "vibrations at 3,000 rpm's and up," and drive ability is fine. I notice the longer i drive the car the worse the "rocks in a can" noise gets. It doesn't do it when i start it up in the morning, but if I sit in traffic it gets worse.

sailorsteve

The noise you describe is classic ZF6. They aren't all noisy, but some are. Thus, the original DM wheel. The noise gets worse when the oil in the trans warms up and thins. The shuddering is another thing, if the clutch gear and flywheel are in good shape and not damaged or warped, I would look for something loose in the driveline- engine mounts, bellhousing or trans attachment, C-beam attachment, etc. If this symptom appeared right after the clutch replacement, that is a good clue as to where to look.

Funrunner99

Alan77, do you have part #'s for the clutch & flywheel you used? Is it a single or twin disk clutch? Has anyone used/likes Centerforce clutches? Prefer one billet flywheel over another? Thanks again for the input!

Alan777

Looks like I have some work to do this winter. The clutch has ~1500-2000 miles on it, so I'm assuming there's a loose drive line component. I will say, the shuddering is VERY annoying while sitting in traffic.

I can look and see if i have the receipts. I bought the car with ~200 miles on the new clutch, but he gave me copies of the receipts IIRC.

Cavi

I would also suggest talking to Redline oils, they will for sure have a syn oil in a heavier weight which might help a bit,if nothing else it will not get as thin and probably will make a difference.
As for the guy who has the sm clutch and did not install the weights, just look at the picture in this post it shows exactly where the weight goes no trial and error. there are five evenly spaced mounting holes for the flywheel bolts and one locating bolt, use this as a guide for placement of the weight.