Talking to Les at McLeod today, we've been trying to figure out the problem of some serious low-speed chatter on clutch engagement with my Street Twin. Originally we thought it might have been a result of switching from a diaphragm to a 3 finger actuation setup for high-rpm use.

As it turns out it apparently, it was a problem with the marcel backings they have been using they will begin using double-backed marcel in the assemblies, they just finished the first one and it cured the chatter problems the customer was having.

Apparently also they will be switching to the 3 finger actuation setup for all Street Twins regardless of RPM range.

 

TrueBlue ChevyDude, I would just like to thank you for the heads up on this problem.

I had recently purchased one of their Street Twins for my 1990 Callaway Twin Turbo but hadn't got around to installing it yet.

I just had a conversation with Les and he said to return it and they would replace the diaphragm with the 3 finger for no charge. I enclosed a letter pointing out your statement about the chattering problem and what was done to cure it. I asked that the disc's be upgraded with the double-backed marcel.

By the way, how is the Street Twin working out for you now? Was the installation straight-forward? Did you have to modify the slave cylinder in any way to get this to work?

The concept of a 3-finger pull-type pressure plate is interesting. I had a hard enough time just getting used to a diaphragm pull-type pressure plate.

Again, thanks for the info. You have saved me a considerable amount of time and grief.

Steve

 

Got your IM, sorry I didn't reply sooner...

Installation wasn't that bad at all over a regular clutch, some model years need the new hydraulics, some don't. I think 89 and up need the new one. Plan on buying thicker left-foot socks, your calf muscle will get quite a workout. I could put up with it on a daily driver, but most people would find it unbearable if they were in stop and go traffic keeping that bad boy pressed in.

The only difference I noticed between the 3 finger and diaphragm was when shifting at high rpm, the clutch disengaged much faster with the 3 finger setup than with the diaphragm. Stab the clutch and rip the gear, pretty much.

Because of the low speed chatter, I couldn't really launch it at all. I had to slowly let the clutch out, so I can't say how the low-speed engagement is. However, the original diaphragm setup took a bit of getting used to. What's required is a clutch/throttle action kinda like reeling in a big fish, for lack of a better analogy. You don't want to slip these clutches if you can avoid it, but you have to work the clutch pedal a bit in first gear to smoothly pull away from a stop. I did alot of stoplight-to-stoplight racing, always "power" driving even when not drag racing, for at least 8k miles back when I was running the L98+ N20, and when I sent it to get rebuilt, they said the clutch discs and pressure plate looked fine.

Of course, if you drive it the way its meant to be driven, it's hard not to fry any street compound tires up into smoke when you leave the line. But I did turn several low 1.7x 60 ft times on BFG Comp TA ZR 275's. You can pretty much put the motor on full-boil and modulate traction using the clutch when leaving the line.

When I originally had it installed w/ stock L98, We had some problems getting the pedal travel exactly where I wanted it, so we fabricated an adjustable actuation rod for the slave cylinder.

I think a motor with all the torque of the Callaway would work quite well with the Street Twin. Good luck, let us know how it works out for you...

 

Thanks. I will talk to McLeod about possibly needing new hydraulics.

 

I just clicked off the first 1000 miles on mine this morning on the way into work. 1990 L98 383. The only difference between this clutch install and a conventional one is the bolted on floater and the standoffs for the floater. It was just a matter of paying attention while disassembling it to install the flywheel.

Mine is a diaphram pressure plate. I haven't had chatter problems with it. It is pretty on/off. There's only a small "window" where it slips. When I installed mine I used the clutch slave cylinder that was with the car. As far as I know it's the stock one. I also didn't do any modifications to the fork pivot.

I'm real happy with it. The pedal is a little stiffer than stock, but not as bad as the mechanical linkage, finger style clutch I had in my old Z-28.

 

SloRvette,

Can you hear the gear lash from the trans when you are driving or at an idle? The cars come with a dual mass flywheel in order to absorb some of the noise and it seems to work for that.

I originally had a Centerforce Dual Friction in the car with a dual mass flywheel and everything was nice and quiet. I wanted to try a lighter flywheel so I got one of the conventional single mass units from Doug Rippie but the trans made so much noise at an idle and while driving(not under power but just a light cruise) that I switched back to the dual mass unit.

Unfortunately, the Centerforce could not hold up to the 609rwhp and 723rwtq that this motor puts out so that is why I am switching to the McLeod.

I have a McLeod 3-finder Street Twin in my '67. It has been in there for almost 2 years now with no problems whatsoever. No doubt that McLeod makes killer stuff.

I am willing to put up with the noise but was just wondering if you had encountered it.

Steve

 

I've got a true 3" dual exhaust with Magnaflow mufflers. I don't hear much but the exhaust.

I made an engine / exhaust / headers / etc. change all at once so I can't compare the dual disk to stock on a noise basis, fairly.

 

Kinda depends how smooth your idle is; I get tranny chatter only in neutral at idle with the clutch engaged. Push the pedal in it goes away, put it in gear it goes away, rev the motor it goes away. It's not much, just that it sounds like rod knock or a broken tranny so my passenger's always panic.


[Modified by gcrouse, 1:42 AM 9/3/2002]