Clutch decision time...need some "chatter" here....no pun intended, let's

I run a Billet steel flywheel. I just had it freshened up by my pal at Brake and Clutch supply.

Paddle style like that ACT clutch seems too harsh. http://proshop.summitracing.com/parts/acl-gm6-hdg6


Here is a Zoom kevlar disc. A lot less than the twin disc McLeod for sure. http://proshop.summitracing.com/parts/zzz-hp5552-1a

 

Hello Paul,

I'm am not going to waste my time putting that organic stock Zoom Perfection clutch back in. Write off.

I will be baselining with a new clutch for certain. I do nit want too much clutch, like thatMcCleod can handle, but it would not be a mistake if that is the choice. I would prefer not to spend more the $400 -$500 on a clutch.

My engine wont be quite as gnarly as yours but expect dyno number near to or north of 550 hp/tq on pump gas.

I wont launch on Nitrous but want the holding assurance if I do juice it which is when I would see numbers closer to and north of 600 hp/tq depending on how I tune the N2O.

I suppose I will know more about what rpm launch works best after some T&T at the track. I assume I will be in the 3500 rpm range for launch. Also figure I do not want to get rpms over 5500 for shift points.

The dyno is going to tell the story on the power curves.

Cheers!

 

Paul, what clutch is currently in the beast?

 

Centerforce DF148552

 

Paul
I was waiting for someone to say center force.
That's what I'm running in all my 4 speed cars and very happy with them
But I've never ran any other style clutch with a 455 so the center force is all I know.

 

It appears preliminary assesment is theMcLeod RST twin disc was not the right choice and should have gone with RXT. That's according to the McLeod tech who I was speaking to trying to trouble shoot my Clutch issue. The summit tech asssured me RST was more than adequate for strip/ street and I challenged him on it but ended up taking his suggestion. Now after 600 miles and 10 passes at the track,McLeod thinks the center disc has a thickness issue which is preventing modulation. McLeod wants me to send it back for forensic study. :af:

 

I'm running a center force as well. Dont recall the exact part number though

 

I'm a "Ram" guy myself had the same clutch in my pops car for 10yrs, and when I run the the car I ride it pretty hard first 100ft. The metallic 6puck is what it's in it, when it goes out another will go back in.

 

What do you mean preventing modulation?


With the CF, I did experience pedal stiffness and the release point going away last fall at Cecil County. After the 2nd or 3rd pass of the day, with the clutch heat soaked, the pedal was grabbing at the top. The fix is the double nut the adjustable lower rod so I can extend it. that's one advantage to the mechanical linkage.

 

Clutch has no slip so its dissenaged or engaged, it grabs...feels like the pedal rod is catching the firewall a couplke inches off the floor on its way back up then pops- which it is not, just best way to describe the foot feel

Pedal / throw out works smoothly when engine is not running. The issue / pedal feel is only when the car is running.

I ruled out air in the hydraulic throwout / pedal set up.

I have it all apart and heading back to McLeod in the morning. I don't see anyhting broken, and theres is 512 miles on it...maybe I tracked it too soon?

 

I've ran and installed pretty much all of them,and I don't really have any negatives on any of them. I have always installed Centerforce clutches in my cars,but Inhave installed Zoom,Hays,Ram,and McLeod in plenty of others. I have installed a few of those McLeod twins. Pretty cool piece,but I just personally haven't needed one when mine are working fine. I do know that one of the twins is living behind a stout big block that gets driven very hard,and it recently broke the Richmond 5-speed. I guess you could debate if the twins put more shock or abuse to the trans or not.

 

I've had similar scenarios with my plethora of clutches and each time it was an adjustment issue. Maybe the TO is too tall and the geometry has the PP and fingers pressing over center which could explain the popping sound.

And those discs are solid, correct? Without sprung hubs and marcels between the friction surfaces? That's typically responsible for the on/off engagement. Had one of those for a summer too.....not a lot of fun in traffic.


I hope they find something wrong with the setup and warranty it.

 

Hey Paul, Everything is built to specs and within tolerances, i.e., hydraulic T/O bearing piston, per spec. There is nothing to adjust but pedal travel:master cylinder which is per spec 1.1" inch.


[/QUOTE]Maybe the TO is too tall and the geometry has the PP and fingers pressing over center which could explain the popping sound. [/QUOTE]

Nope, but spot on with your analysis!! The T/O piston is spot on, travel is 0.443" (Spec is 0.440-0.0445" travel) it is within spec, and there is no "popping sound". I was trying to describe what it acts like, "clutch pedal rod catching" which it is not.

[/QUOTE]And those discs are solid, correct? Without sprung hubs and marcels between the friction surfaces? That's typically responsible for the on/off engagement. Had one of those for a summer too.....not a lot of fun in traffic. [/QUOTE]

It wasn't bad at first, no chatter and very easy on the street, which is why I was sold on the twin disc organic. What do you mean by "marcels"? I measured 0.020" between outer disc and inner flywheel when clutch is disengaged, which agin is right in spec. I couldnt measure the inner set up as it's not accessible when bolted together. It got hot, that's for sure. Also a lot of clutch dust and feels a little dry pasty. Cant see anything that leaked in there. I'll post some pics

[/QUOTE]I hope they find something wrong with the setup and warranty it.[/QUOTE]

Me too I sent backthe T/O bearing also for them to look at. I'm also going to bring the trans back to "Muncie Bill" while it's out for a check up. I am leaning back to where I was going before opting for a diaphragm style and have Rob build an adjustable 10" custom for the 'street sleeper ... we had another good chat yesterday... http://www.advancedclutches.com

 

Marcels are the wave plates between the friction surfaces on a clutch disc.


That bellhousing has a lot of dust in it considering the mileage on it. Something isn't happy in that set up. Hope they can tell you what it is.

 

Thanks Paul, yes, too much material, and it got hot.

I don't know what the minute amount of fluid is that got introduced at one point came from. No leaks on trans or T/O bearing, but it looked like it seeped for, front of trans seal retainer plate.

I hope they can tell me What's wrong...

 

Reading along and waiting to see which way you go need to decide for my project before next year.

 

At this point, I am sticking with the Mcleod RST twin disc....

I will know in another 500-600 miles and some track runs if that is a good decision or not.

...Mini RANT... since Mcleod took it upon themselves, without calling me first, (as they assured me they would) to discuss the findings of the clutch I sent back, and what options I had. They just replaced it at all "warranty" and shipped it back.

I included my hydraulic throw out bearing in the return package with the old clutch so they could inspect it with the clutch. They took it upon themselves, again without talking to me, to rebuild my hydraulic throw out bearing which was like new. I don't know why I even sent it back in hind sight.

The rub is for some unknown reason in the processs of fixing it til it breaks, they used a longer piston than I had in it which I had already set up to this clutch and bellhousing, so now it does not fit within the 0.100" min - 0.250" max clearance. Clearance measures 0.045" with this set up so out of tolerance by 0.055".

I have to wait for them to send me the 0.200" shorter piston, tto get it back within spec. I expect I will have it in hand mid next week.

Of coarse I appreciate the warranty "no questions asked", but it really pisses me off since they did not call me to discuss the findings or cause of disc failure, and they had my throwout bearing in hand to verify they used the right piston,which again did not need to be replaced.

I am glad I verified clearance before putting trans back in and just didn't assume they rebuilt it correctly.

They wont charge for the correct piston but I lost a week(end) and am miffed right now, while all in the spirit of what is, on their end, a good deed / warranty / good customer service.

After talking to Rob Youngblood a few weeks ago, I would seriously look at his single 10" assembly (new aluminum flywheel, non diapraghm, adjustable). Spins up really quick, as it is much lighter than billet steel flywheel. It would be a bit less friendly for the street but would really make a difference in performance.

http://www.advancedclutches.com/index.htm


Stay Tuned.

 

All back together and tearin ass! Don't want to put too much on it until alignment next saturday.

 

i

have one of robs clutch... real nice piece ... not the best to have a superlight flywheel for street manners tho so be careful about going superlight

mine is 11 pounds and is super revvy , clutch disc and flywheel weigh only 22 pounds ,I would consider this a 80% strip 20% street IMO, mind you the trans is not the most street friendly either . I would consider the adjustable pressure plate with a heavier flywheel for better street manners