1997 K2500 6.5 5spd. Solid flywheel.

Anyone use the centerforce dual friction clutch setup.

My truck is on its second clutch in 120,000 miles. Uhhgg. This is my first clutch R/R. The OEM LUK looks weak. Is the centerforce dual friction any better?

Any others?

Per Centerforce online catalog the DF setup requires thier throwout bearing. What's the difference. I am going to replace the slave cylinder too. It looks like a combination one piece unit.

I am running a dual friction in my cummins conversion and it has served me very well. Never has slipped with over 800 ft lbs, and smooth engagement.:D

Thanks, this choice is killing me. The OEM LUK just looked cheap and weak. I haven't seen any others to compare. I saw SouthBend makes a tough unit for the Cummins NV4500 (different input shaft than 6.5) but they are pricey and they recommended a dual mass for the 6.5. I don't want to do that.

LUK is definately the cheapest and is OEM but is questionable on durability for me.:(

I am going to replace the needle pilot bearing with a bronze bushing.

So far the top runner is Centerforce. But I just saw an alternative on Summitracing.com A Hays SuperBrute Clutch Kit. xxxxxxxx~ $320.39}. Comparable to Centerforce price. Claims its heavy duty. Anyone used them before. Where are they made?

edit:
Doing more research I was mistaken {Hay-90-109 ~ $320.39} THIS IS A DUAL MASS CLUTCH KIT FOR 96-2000!!! Production OE was a solid flywheel changed early during the 96 model year.

Hays appears to be a division of Mr. Gasket Corp.

So this leaves Centerforce and Southbend as the only high end clutch kits (that bolt up to factory stuff) for the 6.5 I can find.

I can't speak to the specific clutch kit you are talking about, but I can talk about another kit I had for a different application if that helps.

I used a centerforce kit on a 323GTX rally car I had a long time ago. Construction was great and the actuation was just a tad heavier than stock. The clutch never gave me any problems and served me well dispite the abuse I gave it. Some have said that the CF is a painted OEM with different springs and friction material (but isn't that what is important in a clutch?). Anyways, I would buy another if I had a clutch application.

Hmmmm ? I heard that too recently about Centerforce being a painted OEM pressure plate. Depends on the application. As in this case the slave/master/bellhousing limit the options. Yes the Clutch friction material is important. But on this application (the 6.5) I am looking for the toughest center section. The 6.5 isn't such a powerhouse its not really a slipping problem. Its the harsh diesel vibration and powerstroke that destructs the spring packed centersection (with solid flywheel). Thats what happened to mine the clutch still has disc material to spare. It destructed the neddler roller pilot bearing and disc's center section came apart.

I am ok with OEM flywheel (resurfaced or new) and a new OEM pressure plate or equivalent.

my understanding is that the centerforce performance claims are for high rpm only. If you're winding out to 5 or 6 grand, they hold much better than stock. At low rpm, spring pressure and clutch diameter have more to say than anything else. My cousing put in a centerforce clutch on his truck. It was much more expensive than the stock replacement and it performed exactly the same as the stock clutch....some slippage under extreme conditions (off roading with low rpms).


If you're putting a clutch on a stock car, I'd go with centerforce. For a truck, I'd look for a larger diameter if possible. If your clutch wasn't slipping before (not talking about when it's worn out), maybe the upgrade is just extra money?? Find out at what rpm centerforce claims that they have better holding power than stock. Good luck with it;)

I heard exctly what joispoi said. The higher the rpms you throw at it, the better it locks up. I was going to put one in mine last time I needed a clutch, but I could get the Luk same day and it holds up plenty for the 6.5.

I had to put the centerforce stageIII because the stock unit was slippin anytime I hauled a trailer, specificly towing uphill in OD trying to keep up boost.

The stageIII is a monster, I can drop it in 1st and send a 50 ft rooster tail of mud out behind me, spinning the tires. What it really improved is the clutch friction in 4wd. It grabs the gears and doesn't let go.

joispoi

Yes that is my understanding too. From the little I have read on centerforce it does start extra clamping as low as 2000 RPM (a little extra then as rpms increase so does clamping forces). I have also been told the GM 6.5 NV4500 input shaft and hydraulic slave and master won't stand up to much. I replaced the dinky plastic master cylinder already and the slave looks dinky too so I kind of believe I won't be able to get too much performance with bolt up stuff.

I have also been told that the pressure plate for this application may not be the proprietary centerforce weighted version that really increases clamping with RPM.

But how did the centerforce your cousin used in his truck stand up durability wise? Thats what I am looking for mostly.

(2) OEM LUK discs have come apart with only ~ 60,000 each!!! I don't think its me. I have ~240,000 miles on my little truck's clutch. I know apples and oranges but come on 60,000 miles is pathetic performance. I haven't even towed much with it in the last 30,000 miles.

Yeah, I put a 2 ton cast iron master and slave with a steel line in between. Nylon is not even a choice for me. 30,000 miles since, I've pulled the clutch twice and the centerforce looked good enough to put back in. I had ordered a new unit and the one I had been using hadn't lost a mm of friction pad.

Schiker,

As far as I know, the centerforce clutch my cousin had in his truck held up fine. He put it through some hard use on winter wheeling trips on the glaciers of Iceland, not to mention countless hole-shots and hard shifts in his day to day driving.

I had a similar experience with the clutch on my '93 F250. The clutch throw out bearing went bad at 83,000 miles, but the clutch itself had plenty of wear left on it. The weakest link isn't necessarily the clutch itself.

Try starting a new thread asking what guys have done to beef up their clutches. There's a plenty of R&D to tap into here.

Schiker;
What did you end up doing? I too have gone through 3 clutches in the 170,000mi I have on my truck, and in each case, the friction material was fine (you could still read the labels they painted on the disc) but the hub springs wore out and caused all kinds of annoying problems. I would like to buy something I can put in there and leave alone. I'm sick of dropping the trans on this truck (although, after 6 or 7 times, I'm getting pretty good at it :cool: ) I'm hoping someone found a good solution (and I'm glad I'm not the only one having this problem...)

-Chris

I tried and tried but could not find any different clutch disc with stronger center hub ; so I went back with the OEM LUK setup (at least they are inexpensive). I am hoping the bronze bushing is better than the needle bearing for the pilot bearing. And maybe the needle pilot bearing failing is part of the problem with the clutch disc's hub failing.

Unfortunately the center hubs don't hold up well at all, regardless of who makes them. GM thought they had a better idea when they went to the dual mass flywheel, but it was just a more expensive repair. I tried running a dual mass solid disc with a solid flywheel for a while, and while it worked great, you couldn't lug the engine due to harmonics, so it wasn't the way to go. The centerforce hub isn't any different than the oem since they are both luks.:(

I did some calling around, and from the calls I made, the only clutch that is NOT a LUK center is the ZOOM HP set. I ended up buying one (for $707!!!:eek: ) b/c I'm sick of replacing new-looking clutches b/c the springs wore out. It remains to be seen how the springs are on this clutch (which has a Valeo center), but time will tell. Here's the difference....

New Zoom Kit:
http://www.cfdatasystems.com/images/Chris/ZoomKit1.jpg
http://www.cfdatasystems.com/images/Chris/ZoomKit2.jpg

Old Clutch vs. New:
http://www.cfdatasystems.com/images/Chris/Clutches1.jpg
http://www.cfdatasystems.com/images/Chris/Clutches2.jpg

Old PP vs. New:
http://www.cfdatasystems.com/images/Chris/PressurePlates1.jpg
http://www.cfdatasystems.com/images/Chris/PressurePlates2.jpg

Sorry about allt he links, but the pictures are big, and I didn't want to reduce the size and lose detail just so they'd fit better in the thread.

Anyone tried this clutch before?

-Chris

Chris,

Did you install the zoom clutch? How is it? The pictures look good for the disc. But I can't tell as much difference in the pressure plate except the paint but I did not study photo at work and home dial up is slow for pictures.

What is the foot pressure to push in clutch pedal? How does it do launching in 2nd gear?

Glad to see more options in clutches.

Hubert

I did install the clutch, but I can't tell you much of anything about it yet, b/c the truck is still in about 573 pieces :rolleyes: I'm also doing a water pump, P/S pump, timing chain, rear main seal, oil pan, control arm bushings, clutch master cylinder, hydroboost, and probably some other things I can't think of at the moment. I'm taking a couple days off from work to try to get it all done before the snow hits (the 255/55R17's on the Impala probably won't be much good in the white stuff). As soon as I get her back together and on the road, I'll let you know.

-Chris