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Im in the same boat as you. So many options its hard deciding what is the right fit. I need something that can hold some power. I dont mind a heavier petal but I do want it to last as long as possible. from what I read a twin disc is probably what I need, but Im curious about what others opinions are.
Spec has some nice stuff but they want an arm and a leg and I need mine. Carolina clutch seems to have decent prices, id like to use their 04-113DF but its only rated to 475 and that will be a little too close for me. Im seeing an aluminum Fidanza flywheel for $380. I think im going to go ahead and grab it.
I had good experience with my Fidanza aluminum flywheel. No complaints at all. You're going to notice that you have to pay attention to slipping the clutch to get the car moving a little more than with a 40lb stock unit. OTOH, you'll get better low-gear acceleration, and the upshifts and downshifts will be easier. I have no reason to believe the Carolina aluminum flywheel is any worse. Just make sure you can get replacement friction surfaces for it in the future, if needed.
I had a SPEC kit and the throwout bearing blew its seal and grease up the friction surfaces and I had to do the clutch job all over again. No matter what any company tells you, all new replacement ZF clutch pressure plates are coming from one foundry in China, and they are not as good as the old American or Brazilian Valeos. The throwout bearings are also all sourced from China, and they suck. I searched and paid dearly for a NOS bearing, which is branded INA on the green plastic portion of the bearing.
Im in the same boat as you. So many options its hard deciding what is the right fit. I need something that can hold some power. I dont mind a heavier petal but I do want it to last as long as possible. from what I read a twin disc is probably what I need, but Im curious about what others opinions are.
Spec has some nice stuff but they want an arm and a leg and I need mine. Carolina clutch seems to have decent prices, id like to use their 04-113DF but its only rated to 475 and that will be a little too close for me. Im seeing an aluminum Fidanza flywheel for $380. I think im going to go ahead and grab it.
The price on Amazon is $100 less than at Fidanza. I think that is a good price!
from what I read a twin disc is probably what I need, but Im curious about what others opinions are.
Spec has some nice stuff but they want an arm and a leg and I need mine. Carolina clutch seems to have decent prices, id like to use their 04-113DF but its only rated to 475 and that will be a little too close for me. Im seeing an aluminum Fidanza flywheel for $380. I think im going to go ahead and grab it.
I'm currently running their dual friction kit with the billet steel flywheel, and I'm not very happy with it. The pressure plate I received from them was a cheapo chinese unit that had no signs of being balanced, PN cast into the cover was C70043X . I've also tried an Autozone duralast pressure plate that wasn't great either. I'm currently running my original Valeo which according to ZFDoc is not a US / Brazil made unit. He tells me these can be identified by 'Valeo' stamped into one of the diaphragm fingers.
Anyway, engagement is very choppy with this friction disk. I thought it was getting better as it broke in, but now it seems to be getting worse. Shakes the car violently when you try backing up and sometimes when downshifting to 2nd or 3rd and rev matching isn't perfect. I have to flash the revs up to about 1200 to get it to move in a parking lot without rattling my teeth loose. Mine slips whenever I get into it in 2nd or 3rd. Running a 383 internally balanced Scat stroker kit, Comp Cams XFI280 cam, solid roller lifters and Scorpion shaft mount 1.6 RRs on LE1 original heads. By the numbers it should make around 500-525 at the crank.
Not meaning to bash Carolina Clutch, but the parts they're selling are the same parts everyone else sells under different brands. The flywheel they sold me is a SPEC. There's absolutely nothing special about what they sell, and in the end I got nothing out of them but an expensive education on what not to do.
I've been considering the McLeod 6402307 street twin, but I'm worried they're using the same chinese made pressure plates everyone else uses. For what they're asking for the kit, I'd expect better. We really need a source for good pressure plate for these cars.
Again, all new replacements use a pressure plate that comes from one place in China. Those covers are cast, and there's only one set of molds at this time. So yeah, no matter the brand, it's all the same thing (except Centerforce sticks their little weights on the diaphragm fingers...which tend to fall off). If you're really looking at that McLeod Street Twin setup, I'd personally make the move to a push-style conversion instead. It would give you access to better pressure plates and throwout bearings. You don't need a twin-disk setup for your engine. You're not making more torque than I did*, and as noted mine ran for years on a plain old organic disk and stock pressure plate. Unless they're drag racing or somehow doing other things that are really hard on the clutch, most people overestimate how much clutch grip they really need.
*Clutch and trans specs are one of the few areas where the amount of torque your engine produces actually matters.
Again, all new replacements use a pressure plate that comes from one place in China. Those covers are cast, and there's only one set of molds at this time. So yeah, no matter the brand, it's all the same thing
I was told this same bit of information by Bill, but I'm not sure it's completely accurate.
Here are a few pictures of the Duralast cover. It could just be the same casting with the trans facing surface milled / dressed. Worth noting however are the radiused relief holes in the diaphragm in picture 3. Also, I don't have a picture but the Duralast pressure plate was drilled indicative of having been balanced. The chinese cover I got from CC had no radius around the relief holes, and no signs of having been balanced.
There also exists a chinese made cover that has 'Valeo' cast into this same surface. I don't know if these are still available, but Autozone lists one that's labeled as such and priced a bit higher than their other offerings. I suspect it's where the one that was in my car when I bought it came from. It also has a slightly different type of radiusing around the relief holes.
So I would have to respectfully disagree that they're all the same thing. Having said that, they certainly may have all been assembled on the same (worn out / crooked) jig.
When I pulled the CC clutch cover off I found there was a hotspot in the same 60 degrees of the flywheel and pressure plate, which to my uneducated mind tells me the pressure plate wasn't perfectly parallel to the flywheel. Measuring the offset between the cover mount bosses and the plate seems to reinforce my theory (note the sharpie writing).
If memory serves, the Duralast pressure plate had more evenly distributed hotspotting, but I ran it with an organic / organic disk. I still have both so I'll look when I get home.
I swapped back to the used Valeo cover and DF disk because I didn't like the pedal travel of either the two C70043 covers. They seemed to fully engage about 2/3 out. But the Valeo is even worse with the centerforce DF disk. Makes me wish I'd never taken my DMF out - it engaged within the first 1/3 of pedal travel (i.e. closer to the floor) and was very easy to modulate / feather while parking. And if memory serves the Duralast also engaged quite roughly (shakes the car).
Originally Posted by MatthewMiller
Unless they're drag racing or somehow doing other things that are really hard on the clutch, most people overestimate how much clutch grip they really need.
I respect what you're saying. I think in my case I got an exceptionally bad part (the chinese cover) that when paired with an unforgiving dual friction disk amounted to severely rough engagement. Unfortunately my rig is internally balanced now so going back to the DMF isn't an option without some really creative machine work to neutral balance it. I'm also disappointed with the Valeo cover and DF disk because I'm certain I'm smelling the metallic pucks burning when I exit a corner in 2nd or 3rd at full throttle, on General GMAX tires (not exactly the grippiest skins available).
Incidentally, I'd be interested to know from folks who've dropped the trans and pulled the engine, which method is easier. Having pulled my engine out 4+ times (I've actually lost count) I think yanking the engine may be less work assuming your exhaust will come off without using a torch. Whatever the case I'm not wanting to do this too many more times, so I'd like to get the best clutch setup I can that will handle the torque and last long enough for me to get some enjoyment out of the car before they put me in a home.
Again, all new replacements use a pressure plate that comes from one place in China. Those covers are cast, and there's only one set of molds at this time. So yeah, no matter the brand, it's all the same thing (except Centerforce sticks their little weights on the diaphragm fingers...which tend to fall off). If you're really looking at that McLeod Street Twin setup, I'd personally make the move to a push-style conversion instead. It would give you access to better pressure plates and throwout bearings. You don't need a twin-disk setup for your engine. You're not making more torque than I did*, and as noted mine ran for years on a plain old organic disk and stock pressure plate. Unless they're drag racing or somehow doing other things that are really hard on the clutch, most people overestimate how much clutch grip they really need.
*Clutch and trans specs are one of the few areas where the amount of torque your engine produces actually matters.
So should people be looking to keep their stock pressure plate?
So should people be looking to keep their stock pressure plate?
I have another post before this that hasn't been approved yet due to external links or ??? that may be relevant.
But yes, especially if you've an original LT4 Valeo. These were the best due to higher clamp pressure. Allegedly years ago someone bought a pallet of them that represented GMs entire spares stock.
Edit: Also, if you go to a single mass flywheel - especially an aluminum one, I'd highly recommend getting the countershaft shim kit for the ZF. My blue tag rattles horribly with the steel flywheel.
I have another post before this that hasn't been approved yet due to external links or ??? that may be relevant.
But yes, especially if you've an original LT4 Valeo. These were the best due to higher clamp pressure. Allegedly years ago someone bought a pallet of them that represented GMs entire spares stock.
Edit: Also, if you go to a single mass flywheel - especially an aluminum one, I'd highly recommend getting the countershaft shim kit for the ZF. My blue tag rattles horribly with the steel flywheel.
ok, so I guess ill go ahead and inspect my TO bearing and go from there. Is there any way to refurbish these? Can I clean up good with brake part cleaner, or will that ruin the grease in it?
You can have your original Valeo unit resurfaced (if it even needs it - I think people assume some color patterns means it's shot but it may not be). If it's resurfaced, the shop has to remove the same amount of material from the pedestals as they do from the friction surface. I don't think you can rehab your TO bearing. It's a sealed (hopefully) bearing.
I'd be interested to know who you talked to that told you this. The clutch reman place I know told me it's riveted together and isn't serviceable. I suppose the rivets could be drilled out and replaced, but can that be done economically considering what people need to make to survive these days?
My post from earlier was finally approved by the mods. I'm not wanting to showboat or be a clickbait *****, I had a question at the end and some pictures and what I feel is relevant information to the subject.
I'd be interested to know who you talked to that told you this. The clutch reman place I know told me it's riveted together and isn't serviceable. I suppose the rivets could be drilled out and replaced, but can that be done economically considering what people need to make to survive these days?
My post from earlier was finally approved by the mods. I'm not wanting to showboat or be a clickbait *****, I had a question at the end and some pictures and what I feel is relevant information to the subject.
Jim Jandick from Power Torque Solutions has now retired from that work. But he used to be the other guru of C4 clutches, along with ZF Doc. He sold me an original GM unit from their C4 race program (lightened 2lbs and with higher clamping force) that had been resurfaced. He said only some places know how to do it. I got the impression that they didn't take it apart, but I'm honestly not sure. I'm sure it's not serviceable officially, so the question is who can either chuck in a machine still assembled, or who can take it apart and put it back together after the machining is done. If it was riveted at the factory, it must be possible to drill them out and rivet it back together. But that sounds like a lot of work!
Last edited by MatthewMiller; 04-22-2020 at 09:28 PM.
Jim Jandick from Power Torque Solutions has now retired from that work. But he used to be the other guru of C4 clutches, along with ZF Doc.
That is exactly what I was most afraid you would reply with. This hobby will die in the dust if we don't get more young people interested in it. I realized this when I had my block bored to 4.040", had to explain to the machinist what a gen2 LT-1 sbc was, and realized immediately that he had no earthly idea WTF I was talking about with reverse cooling and 52 cc combustion chambers. In 1989 I proudly owned a copy of Smokey Yunick's Power Secrets, and posters of the LT5 and LT1 engines that were more coveted than the Lamborghini Countach and Claudia Schiffer posters on my college apartment wall next to them.
The LS engines are a technological marvel, and I will openly admit I covet owning a C8 more than keeping my family alive and well. But the gen 3+ engines wouldn't exist without the breakthroughs that started with the ZR-1, the 91 LT-1, and this beast of a transmission.
I guess it's up to us (me?) to find and / or improvise the tooling to fix these cheap chinese crap pressure plates.
Quite depressing to learn. I've got plenty of other projects demanding my attention (google: diy-ltcc).
That is exactly what I was most afraid you would reply with. This hobby will die in the dust if we don't get more young people interested in it.
I guess it's up to us (me?) to find and / or improvise the tooling to fix these cheap chinese crap pressure plates.
You could contact ZF Doc and see if he knows someone who does it. But there have to be other people who know the right machine shop. I don't know how to contact Jim anymore. However, I was digging through old emails and came across one of the replies he sent to me when I was doing my replacement:
Originally Posted by Jim Jandik
Yes, the steel friction rings in the pressure plates can be resurfaced. Actually, there are two ways to accomplish this. The aluminum legs on the pressure plate prevent a resurfacing process like what is done to flywheels since they are in the way to make a complete pass with the cutting stone. My guys at the race motor shop in Des Moines are able to use a different process to remove the hotspots, but this contours whatever cup there is to the steel friction ring (all of these plates cup high at the outside edge, same as the DMF's). Option two is to physically remove the friction ring from the aluminum housing, then it can be milled square and the hotspots removed. Then the plate is riveted back together and rebalanced. The legs are then re-machined to account for the material that was removed from the steel friction surface (exactly what you stated). This process was used on the LT4 race plate. I've measured new LT1/LT4/LT5 plates from Valeo and the distance from the face of the steel friction ring to the face of the aluminum bolt tab legs measures between .195" to .205". I try to observe that same range.
So there you have it, straight from the expert's typing fingers. I don't know what shop in Des Moines he was using, but that kind of narrows things down.
Here are some more detailed pics of the pressure plate that came out of my car. 133K mile. Then it sat for 11 years. I have no clue why the pressure plate rubbed the clutch fork? The ball stud looks fine. The Fork doesn't look bent.
I did order the fidanza aluminum flywheel today. I will order the shim kit.
With all of the above information I have no idea what clutch to buy???
04-21-2020, 11:33 PM
Carolina Clutch and Flywheel
