hey guys, I have the tranny out on my 95 6 speed, and Im a little concerned about my dual mass flywheel. I can move the plates by hand fairly easily. How much resistance should there be and how can I tell if its bad? If it is, whats the best lightweight replacement that wont shatter the bank?

Thanks
John

 

I forget what the spec is but someone will probably chime in. I believe you want less than an inch of play between the plates, anything more indicates too much wear. How many miles on it? I went with Fidanza aluminum on my 93 6spd, but I believe the camaro single mass steel is more streetable. That flywheel does need to be machined down to fit. If you're motor is still stock and you don't hit the drag strip, then another dual mass replacement is the best route. Carolina Clutch has some of the best prices.

 

As far as a new stock (DM) replacement, I do beleive that Carolina Clutch has THE best prices. I recently confirmed this with Bill at zfdoc.com.

I have a modified engine and I still swear by the DM setup, mostly because I don't drag race. The stock setup works just fine with my mods. I had the ultra-light Fidanza in last year and despised it with every fiber of my being.

 

Wow. Tell us how you really feel Brad.

.
I had the ultra-light Fidanza in last year and despised it with every fiber of my being.[/QUOTE]

 

yup, thats right!

 

Just replaced the DM and clutch assembly in my 89. Ordered it through Carolina clutch. Cost me right at $1,000.00 including shipping!

 

I agree with Brad... the fidenza is not good for this car on the street. It just doesn't cut it.

It's just too light. The Camaro SMF is a nice option.

And yes, your DM is shot. It should not move by hand. I will dbl check the specs... but I think it's done.

 

thanks guys, sounds like I need a new flywheel which is lighter, the camaro 6sp fw or the 4+3 vette fw? I think I wanna go with the lightest GM FW

thanks again
John

 

I just bought a new dual mass flywheel for my '91 and got it for $849 (including shipping) from http://www.gmpartsdirect.com. It's actually a dealer in the Winston/Salem NC area (as opposed to GM itself). Great prices on everything (compared to dealer prices).

Once in the site, click on the "Catalog" tab at the top and the rest if pretty self-explanitory. You have to load up your shopping cart and proceed to checkout to see the prices.

Side bar: I found out about gmpartsdirect.com (and the cheaper prices) days after I bought a new clutch and pressure plate from a local dealer (Diamond Chevrolet in Charlotte). I took the parts back to Diamond Chevrolet, showed them the prices from the gmpartsdirect.com site, and asked what the deal was and why their prices (the dealer's prices) were so much higher. Diamond Chevrolet told me it's not GM, it's a dealer out of the Winston/Salem area and they're basically selling the parts at cost and making their money on shipping (but gmpartsdirect prices are still much lower than dealer prices). They actually asked if they could make a copy of the pricing quote I had from gmpartsdirect.

I told Diamond Chevrolet I didn't really care how gmpartsdirect was making their money, but what I did care about was the fact that Diamond Chevrolet just charged me $650 for pressure plate and clutch that I could of purchased from gmpartsdirect for $433 (with shipping). I said I'd like to return the pressure plate and clutch and, in addition to getting snotty about the gmpartsdirect thing, they said they wouldn't do it because I'd already opened the boxes. So, I told them that's the last time they'll see me, my two Corvettes, and my Blazer, which didn't really seem to bother them. I'll be sure to send the owner a note when I buy a C6 somewhere else.

 

Dealers has to make their money some how. Most however will work with you. They realize times are changing especially with the internet as competition. A few of them here sell parts to everyone at 17% over their cost. I don't really know how GMPARTSDIRECT is selling at dealer cost on many items. I guess it is because they will charge a handling fee, which I am not sure if its by the single part of by the order. Either way, a lot of people have been satisfied with their service.

Dealers also have a very high overhead that they have to cover. But even then I don't condone gouging customers as what happened to a freind of mine at a local dealer here in Portland. He was charged over 7 hours to repair an open circuit in his trucks digital mirror. This harness was easily accessible, I could have removed it less than 15 minutes in its entireity. With common sense and wiring knowledge it should have never have taken 7+ hours. I posted the story in the off topic forums, got a lot of mixed views. In any case its there, and I wanted people to be aware of who they were dealing with.

 

The DM flywheel from Carolina Clutch is going to be about $600.00. www.carolinaclutch.com, call and ask for Tom. You will also need a weight set. This set is rather cheap, really, and will allow you to match your old DM to the new DM ounce for ounce. You see, the DM is the rear balancer for these engines. As such, they are fine tuned to each engine.

If you go SM, make sure you match balance the weight. This is where the same out of balance condition is applied to the new flywheel.

As for which GM SM is lighter? I would use the Fbody piece. You must understand that lighter is not always better!!!!! When the ZF warms up, the flywheel is acting as a noise buffer. When lugging the engine, or cruising in 6th, a dull roar - er, deafening resonance - will kick up. It's most annoying.

When I rebuild my engine, I will either rebuild and rebalance with a Fbody SM or get a new DM and have it balanced... I was stupid and lost the old DM when I replaced the clutch. It got lost in the shuffle of my move to CA. dumb dumb dumb.

I have spoken to many drag racers who are more comfortable with the heavier DM on the launch. Others much prefer the grip of a killer SM with a stage III unit. Auto-x'ers seem to prefer the lighter flywheel to keep the engine spinning... but gee, these are big V8s with quite a bit of low-end torque, and the heavier flywheel only adds to that. If these were V10 or V12 engines of the same size, their RPMS would be much higher, and they would not have the low end torque, so they would trade that for 8000 RPM redlines... hence, a lighter flywheel would be a good choice. But these engines were not designed to deal with lighter flywheels.

The numbers are deceiving... they claim you "gain power" or "free up power" by adding the lighter flywheel... it doesn't work that way. The loss of weight removes the mass that the engine is using to STORE torque... Hence, the flywheel effect. I find with my Fidenza and Stage I clutch that I have to slip it or dump it. It just isn't all that street friendly.

Oh, GM Parts Direct eats you ALIVE on S&H. I prefer Chris at Superior Chevy. I also prefer talking to a person then depending on a faceless website.

 

bogus, every word you wrote is dead on

 

Well,
I have had quite the ordeal with my SM conversion that started with a worn pivot ball and an PP with slightly too long roll pins. Anyway after dealing with a chattering clutch for almost 6 months I finally got the thing changed (Got a good deal from Brad because he hated it) and all is well in ZF land now (4 stitches later because of a leaky rear seal). Here is my take since I changed the fluid and installed a new pivot ball and clutch/PP I like the Fidanza. I still have a slight rattle at idle but not bad, I do have the blue tag ZF, but drivability is great. Brad complained about engine breaking with the Al FW but I don't seem to have this problem, maybe because of more cubes. I think the SM conversion is a good alternative to a $600 FW but would recommend a steal FW -vs.- Alm. For a little added weight and to ensure you don't have similar braking problems. The DM is still a good alternative as well but I just don't like the idea you can't turn the thing. For instance If I had went the DM way I would be out another $600 because of the PP problem I had, there was severe bluing on the Fidanza insert. Instead I bought a $60 insert and replaced it or if I had went steal I could have turned it. I think you will be fine either way but I have heard many complain about noise with the Black tag ZF, SM, w/alum FW combo so I would avoid that set up if at all possible and go with a heavier FW.

 

If I go the camaro route, whats involved? is it simply a fw swap with the FW machined .090? it will need balancing too right? does it have holes similar to the DM? what part number or year/engine combo should I ask for?

Thanks
John

 

If you want to use the Fbody piece, you need a flywheel from a 1993-1997 Fbody, V8 car, the parts bolt up perfectly.

It will have to be machined .090, as stated, and match balanced, as stated above.

you must use the corvette pressure plate, and the camaro friction disc.

 

This is incorrect. Part of the check in the Factory Service Manual involves moving one portion of the DM flywheel by hand. I just went thru this when I rebuilt my engine and wanted to check the flywheel before reassembly.

I'm on the road and don't have access to my manuals. Get the FACTORY manual and perform the test before wasting $600.

 

does anyone have a service manual that would be willing to scan the test procedure for me? Id really appreciate it as this is money I cant really afford right now on a flywheel. Thanks a million

John

 

the spec is 1.378 in, and is used when measuring the lash between the 2 plates. essentially rotating the outer mass clockwise till it stops and marking the spot, then counterclockwise till it stops and marking the spot. Then measure the distance and compare to spec.

Also, DMF's get surfaced every day. There are a ton of them out there, largely on the diesel trucks. alot of these get faced on a brake lathe, taking off 5 thousands, and work just fine as long as there isn't any cracking or excessive/deep hot spots.

 

Yes, absolutely.

But comparing the DM on a diesel truck to the Vette DM is not a fair comparison... It's why veterarians don't do surgury on people. Sure, animals are kinda like the human condition, but they aren't quite the same.

The three big reasons why one should not turn a DM on a Vette:

1) Space. The distances inside the bell housing are soooo tight, that removing .005 could be too much. Seriously.

2) Most cutting fluids will distroy the rubber membrain inside the DM.

3) The aforementioned rubber membrain will not last. It's good for no more then 125k miles... and that's that.

Please, I understand your logic, but it's not a good idea to compare something so very alien as an OTR truck with a Vette.

 

I enjoy your posts as they are informative.

The trucks I am speaking of are powerstroke fords, f 250', Dodge's, s etc.. I was not even thinking about "over the road trucks". The guys I work with do not like them either, but it is not because they cant' turn them.

I think the tolerances are tight, but .005 could be shimmed, and is immaterial in this application (just current my opinion), especially when the the specs begin changing from day one and the hydraulic system is designed to self adjust. I could be wrong.

I agree with your post, and wonder if it is an absolute. I will find out as I just put my 40K mi "carefully" surfaced DMF and centerforce clutch in. I decided not to shim it. We'll see.