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Clutch opinions/experiences

Oh ok, that is good to know ak, I am a little hesitant like you said about one of those clutches behind a 6.5. I have gotten in contact with a guy from CF so we will see what he says. What I like about Phoenix Friction is that it says they have been doing fleet work for companies like UPS and Fedex for years, so I guess that could be seen as a good thing, they have done a lot of work with diesels. What I don't like is that this kit could potentially just be an assembly of the cheapest parts with the exception of the disc which would be their own. I think I will contact them about that.
 
Ok guys update:

I spent 45 minutes on the phone with a gentleman named Bill from Phoenix Friction. Extremely nice guy. He was genuinely concerned about my clutch problems and had a wealth of info on how their clutch discs are made. He seems to think that either my flywheel or clutch set is incorrect. But here is the deal. He led me to believe the stage 3 clutch would not be the way to go with me. He also mentioned they were currently sorting through some issues with the 6.5 stage 3 clutch because the disc design and shallow bolt bore of the flywheel was causing the crank bolts to begin rubbing the rivets in the center section of this disc in a short amount of time. In addition, he was also a bit leary about using their OEM replacement organic clutch due to my performance modifications that place me well above stock power levels. However, the fact that I have been going 2.5 years on a crappy oem replacement with no slippage made him think their organic could probably work. Unfortunately PF does not make a dual friction for the 6.5.Again, very nice guy.

I also emailed someone from Centerforce and he told me the clutch engages fully just like any other clutch, the flyweights simply increase the force on the disc starting at about 1000 rpm. I asked him about pedal feel and he has not gotten back to me yet. ak, how is the pedal feel on your CF clutches?

Currently I am still torn. I am leaning in the direction of CF still, but I don't know.
 
The CF dual friction tends to have a rather soft pedal feel compared to most any other clutch out there. I put one in teh VETTE I just did, and it has a nice soft pedal feel up to about 6000, above that the weights make it a tad stiff but not bad. Behind a diesel I owuldn't think the weights would do much asm ost say you need to get up to about 3500 before they make much of a difference. The nagain maybe CF specifically sets the weights furthur out or makes them heavier for the diesel application since it is a lower RPM set-up. How much are you looking to pay as the southbend stock replacement is about the same price as the CF clutch kit.
 
Thats good to know ak, that is a big part of my consideration.
Ferm you bring up a good point. Although the CF is a dual friction whereas the $400 SBC is the "stock" replacement.

Here is my question, the SBC $400 clutch says its rated for stock hp and torque, and so is every other clutch, like the phoenix friction for $250. Then there is Napa at $240 and others in that range. If they are all designed/rated for stock hp and torque, why the big price difference?? Does one last longer. I mean if the SB disc is the same material as the stock replacement, then why is it so much more expensive?
 
vdb11 said:
Thats good to know ak, that is a big part of my consideration.
Ferm you bring up a good point. Although the CF is a dual friction whereas the $400 SBC is the "stock" replacement.

Here is my question, the SBC $400 clutch says its rated for stock hp and torque, and so is every other clutch, like the phoenix friction for $250. Then there is Napa at $240 and others in that range. If they are all designed/rated for stock hp and torque, why the big price difference?? Does one last longer. I mean if the SB disc is the same material as the stock replacement, then why is it so much more expensive?
Click to expand...

If you go to SB site and look up the rating on there clutch, it is rated for 475HP or 1000 ft lbs of torque, so Iwould say it is more than up to holding a 6.5.
 
Where do you see that ferm? I downloaded the excel file with the catalog of all their clutches and they only offer two clutches for the 92 6.5, one which says "stock replacement" and says stock for hp and torque and then one kevlar clutch rated at 375 hp and 750 torque.
 
vdb11 said:
Where do you see that ferm? I downloaded the excel file with the catalog of all their clutches and they only offer two clutches for the 92 6.5, one which says "stock replacement" and says stock for hp and torque and then one kevlar clutch rated at 375 hp and 750 torque.
Click to expand...


Theres an option for download searchable catalog, and the 6.5 clutch kit number I found was for a 163 according to SUMMIT. In there searchable catalog it lists the 163 clutch as rated for 475HP and 1000 torque.
 
Just because a company claims a product rating, it does not meant those claims are true or that their product is worth a hoot.

The throw out bearing - unknown brand - that we shit canned when we changed the NV4500 out, was definitely inferior to the GM throw out that I replaced it with. The clutch looked a little chintzy too. This was done by the previous owner so I do not know what brand of parts he used.
 
I had a valeo in mine it was good it grabbed nicely and never slipped but i was haveing problems with it not disengaging properly in the summer (seemed to be a warm weather problem) since i just pulled the motor and tranny i found that i was having clutch fork problems and my throw out bearing was junk, (got it from the parts store, will deffanatly find a better one) also i put a pilot bushing in instead of the pilot bearing and it seems that the bushing was spinning in the crank so it must have seized on the inputshaft. not sure how i will go on that the input bearings are always shot and the bushing didnt last either
 
Ok guys I bit the bullet....

I decided on the Centerforce Dual Friction Clutch. I decided I am going to keep my flywheel from Advance, as I figure most new flywheels are made overseas anyway. I could have purchased the Phoenix friction stock kit for much less, or any other clutch for that matter. In fact I spent more (bought directly from the CF website) than the stock South Bend replacement. Time will tell if I made a good choice. I will be certain to let all of you know how it goes. I also purchased a rebuild kit for the NV4500 as well.

Things I still need: throwout bearing (from what I have gathered from you guys I will get this at the dealer), clutch fork pivot ball stud (also from the dealer because I cannot find anyone that sells one), pilot bushing (any auto store?) and the right GM nv4500 fluid (from dealer).

This is alot of money for me to spend but I want to do this right this time. I want this thing to shift better than new. I really appreciate all of the help you guys have given me over the last few days. You have been a huge help! I will be sure to update as this project gets underway. Assuming things ship in a timely manner, I should still be able to pull this off next week (Thanksgiving break for classes).
 
what is casueing you to want to rebuild the Nv4500? i rebuilt mine with a buddy that builds trannys for a living but i had a couple bad syncros.
 
Well it whines, rattles and carries on a good bit at low rpms, and I think this bad clutch has only made it worse. The input shaft had some play in it last time I had the tranny out. It doesn't shift smooth either. I figured while I am replacing the clutch I might as well do the transmission.
 
hopefully you dont have to take the main shaft apart that requires a fairly good size press. if you are just going to do bearings and a new input shaft that shouldnt be to bad
 
I had to take mine to a machine shop several times to use their big press and some heavier tools. Mine was abused and warped causing it to need several new hard parts. After the rebuild I haven't gotten is wrapped into my truck yet but free shifting it feels better than any manual tranny I've owned took alot of money though.

Got my engines top end apart for studs then att and it has taken priority over wrestling the tranny alone.
 
Im hoping with the low miles the hard parts are still good. The truck only has 107k, I bought it when it had 93k. It was abused when it was younger but I am hoping it has gotten that bad yet.

Good luck with the studs! I put them in mine a while back and I have hit 25 psi on occasion with the vgt turbo and the hx52 I am running now with no blown gasket! Thats for a very short time though.
 
Mine will be a tow rig with the 240k mile bottom end. Eventually I would like to do a center mount so the pass side heads egts are better balanced for towing.
 
Agreed. After the tranny and clutch are done, my next project is the center mount set up. I am already collecting parts :D

I am hoping the nv is just in need of bearings and synchros. I don't think it was ever a tow pig but it was not treated well when it was younger I know that for sure.
 
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