Attention Centerforce clutch users?

[BadBrad]

Are all you guys using an adjustable ball stud?

Forum search says many of you are if you have a stock or otherwise bellhousing.

If so are you using the Lakewood stud?

Thanks for your input.

[RACEBUICKS]

I was using a lakewood and the stock ball stud and Z bar with the centerforce with no issues.....well except the trans wouldnt shift under full throttle. Too much torque!! .

[MPRY1]

I was using a lakewood and the stock ball stud and Z bar with the centerforce with no issues.....well except the trans wouldnt shift under full throttle. Too much torque!! .

Thats good to hear, since I'm planning on going with the Centerforce. Except for the not shifting under load part LOL :laugh:

Anyway, Mike, did you run the CF throwout bearing or the Buick one? I have heard pro and con in regards to using the CF bearing. :Do No:

[RACEBUICKS]

I had the stock throwout bearing

[72staged]

I am using a Centerforce with a Kleiner repro fork and clutch pedal push rod with a stock stud an Z-bar with a Summit throwout. There is something odd with this combo as I had to make my fork pushrod longer than others it seems. I could not get enough pedal to release the clutch with the stock component setup. I actually changed to the component combination with the spherical rod end discussed in a previous thread as I like the way it works. And then, I still had to add 3/4 in to suggested pushrod. I am not a 4-speed expert. I was wondering this whole time if the Centerforce clutch fingers have a thinner radial depth? If so, that may explain the deeper clutch release? Or...I put the damned thing together wrong?

-Mike

[flynbuick]

As I recall the Centerforce throw out bearing, which I felt you need to use with its clutch and pressure plate, is not as tall as the stock bearing. Thus you need to also use the Lakewood adjustable pivot ball to make up for the change in the overall geometry of the system.

[GSX-PKV]

I was using a lakewood and the stock ball stud and Z bar with the centerforce with no issues.....well except the trans wouldnt shift under full throttle. Too much torque!! .

I hooked a "torque strap" (similar to the ones the turbo V6 guys use) from the front drivers side of my block to the frame and it eliminated the problem I once had of missing shifts at WOT. Paul

[RACEBUICKS]

I hooked a "torque strap" (similar to the ones the turbo V6 guys use) from the front drivers side of my block to the frame and it eliminated the problem I once had of missing shifts at WOT. Paul

I did too, mine was at the rear of the block and yet I had to idle the motor to shift. The muchie I had was twisting under full throttle so bad I guess. :eek2:
One of the last street races I had the guy wanted to fight because he thought I was messing with him. Run away then lift to shift he would catch up then I would be ripping away again then lift to shift, then run away. Each time I lifted he was pulling up on me but never got around. He was really pissed off for some reason.:Do No: :Brow:

[PaulGS]

There was a great article in Hot Rod a few years back that showed all the critical dimensions on manual transmission cars.

There is a critical dimension on the flywheel thickness, as well as the depth of the bellhousing.

I can tell you through experience that the adjustable pivots can come loose, and if they do, you have to pull the tranny to fix it.......:blast:

[72staged]

As I recall the Centerforce throw out bearing, which I felt you need to use with its clutch and pressure plate, is not as tall as the stock bearing. Thus you need to also use the Lakewood adjustable pivot ball to make up for the change in the overall geometry of the system.


Thanks for the info Jim, Everything seems to work alright with the longer push rod. But if I encounter any issues, I will now know where to focus my attention.

-Thanks, Mike

[71gs3504sp]

Hi

Is there good stock clutch out there that will would work with a stock 455 and 4 speed.

George

[flynbuick]

Centerforce with the light pedal pressure is the answer for your application.The model is called the dual friction.

[PaulGS]

I use the CenterForce II with my 455.

Light pedal and works great.

[BadBrad]

As I recall the Centerforce throw out bearing, which I felt you need to use with its clutch and pressure plate, is not as tall as the stock bearing. Thus you need to also use the Lakewood adjustable pivot ball to make up for the change in the overall geometry of the system.

Jim,

If the bearing is shorter you'd have to increase the length of the stud. The distance would be directly proportional to the difference in the stock bearing versus the centerforce bearing.

Make sense?

[flynbuick]

Yes. I took a stock bearing and the Centerforce bearing and put them side by side one time a couple of years back.

[GSX-Rated]

I am probably going to catch a lot of flack for this, but I am using a Centerforce dual friction clutch with their throwout bearing, 11 inch billet flywheel from Poston, but I am using a z-bar assembly w/stud from NPD for a Chevelle. It was $44 for the assy that came w/everything. All I had to do was bend the lower z-bar arm straight & it worked fine. Before that I had an orig Buick one & it would hit the headers. I wasn't worried about being factory correct cause my car was originally an auto.

:3gears:

[Steve Schiebel]

I've got an 11" Centerforce II kit (PP, disc and N1716 TO bearing) behind a TA Perf flywheel. I'd like to improve the pedal actuation of my clutch, I'd like the pedal travel to release the clutch sooner and have a longer travel distance to get full release/engage. I have an external hydraulic slave actuating the clutch fork. Now the pedal must be almost fully down to its stop near the floor befor the clutch disengages. The pedal only rises from the stop and inch or two before the clutch is fully engaged. I've gotten used to it and can operate it just fine.

I believe I have a few variables I can play with, but I'm poor in geometry and would like some input in decipering the fork actuation parameters. I've read where a taller TO bearing will produce the same results as a longer, adjustable pivot stud, true? What exactly is the result from making that change? See attached TO bearing photo.

Since my '71 Riv never came with a MT, I've had to mix& match components. I sure wish I knew the P/N of a '71 LeSabre's clutch fork when equipped with a 455 and 3spd. Maybe I could track down a photo and compare it to what's available now.

My other questions have to do with clutch fork length and shape. How does the fork length from the pivot stud to the outer actuated end affect leverage? How does the angle (bend) of the fork from the pivot stud to the outer actuated end affect leverage?

[BadBrad]

Here is some additional helpful and nearly free (its in the public domain) info:

http://books.google.com/books?id=iVpxmid9oNUC&pg=PA70&lpg=PA70&dq=centerforce+ball+stud+GM&source=web&ots=i0k74_Bb1N&sig=YHjREE7hUECSfMWp_wx71Kt0iJ0&hl=en#PPA70,M1

Sorry it comes from Chivy literature. :boring: At least it's relevant.

The guy at Centerforce says there are two GM ballstuds. I found on the net 1.375inch is PN3729000; the other: 1.6875 PN3790556. Both are still available.

He did suggest the adjustable Lakewood though. If your flywheel is thinner or thicker than stock gotta use the ballstud to correct.

I just don't want to button this all together and then have to send to the shop 'cuz I'm worn out and refuse to R&R another tranny. That sucks.

[little d]

all of our clutch adjusting rods are now 3/4" longer than stock , hope this will fix everyones problem no matter what the clutch preference. We can also build this part with a solid oillite bushing for the thrashers. just state which you want we ordering. Dave

[MPRY1]

Thanks Dave,

That should make things a lot easier. Quick question, The spring on my fork has a busted off tab. Is it possible to replace the spring and rivet, and if so where does one find these parts?

[GSX-Rated]

NPD (National Parts Depot) has it. Mine busted off an ear also.

[MPRY1]

Great news thanks for the info!!! :beers2:

[MPRY1]

I downloaded the NPD catalog and looked through it. I can't find the retainer spring anywhere. You wouldn't happen to have a part number or can guide me to where it's at in the catalog could you?

[BadBrad]

So I measured my flywheel thickness and after 300K+ miles and the recent resurface I found it is .038 inches under the minimum for the Centerforce at .960 inches. What this really means is I need to install an adjustable ball stud and push it out from the back of the bellhousing 0.038 inches more than stock.

I hope some of you guys find this helpful. I for one have learned too much about clutch geometry this week.