Beware of dual disc clutches

[rsimoes]

I almost installed a dual disc clutch on my car and changed to single disc last minute due to required modifications I was not comfortable with, like trimming the bearing retainer and shaving part of the bolt heads that hold the bearing retainer on the trans.

What they don't tell you on the phone (tech support) and in the descriptions, is that there are actually many draw backs to this setup. Only the paperwork that comes with it, has all these warnings:

1) It rattles
2) Should not be used in hot lapping
3) No engine breaking
4) No burning rubber in wet and then hit dry pavement, as it could destroy the clutch
5) Should not be used with taller gears than 4.10 (lower numerically) on dyno
6) Miss shifts will ruin the clutch
7) Always start in 1st gear
8) Rev match when downshifting for power, or it could damage the clutch
9) if you really want to race, upgrade to another high performance clutch they make.

Among other installation modification that may be required depending on application.

Although I don't know if this is an exaggeration so they don't get sued, it makes me uncomfortable putting one in my car. . . as it sounds to defeat the purpose of having a dual disc clutch. . .

I just thought I would pass this along in case you're considering one. .. . .

[double ugly]

I was thinking of geting the Mcleod dual disc clutch kit. Don't?
John

[rsimoes]

The draw backs I listed above "talked" me out of it. That being said, I am NO expert. . . ask them about the drawbacks above. . . . (most have to do with the metal anti-rattle straps for the metal piece between the discs that can get bent and make the clutch bind. . .)

I went with this setup intead:

12 inch race clutch Mcleod 260873
Pressure Plate: Mcleod 360821
Aluminum flywheel: Mcleod 563210
pilot bearing SKF B50HD
pressure plate bolts ARP 150-2201
flywheel bolts ARP 200-2802

[Stentor]

Originally Posted by rsimoes

Lew,
I just returned my RAM street twin because it requires modification of the bearing retainer in the shaft and a special throw out bearing. Must people have not done this, so I did not want to try it on my car and possibly void the trans warranty. I just felt safer going with a proven setup. However, the twins can handle like 1200 ft-lbs.

I chose the standard 12 inch McLeod setup that Kirkham uses.

How did you get oil on it?

Per your post a few months ago, I thought you already ditched the twin disc clutch?

[Badger]

Sounds like CYA to me. The main reason to go to a dual disc setup (with smaller diameters and a flexplate instead of a std dia. flywheel) is to reduce inertial mass....No point in keeping the same diameter (12") and going dual as that just increases the mass and kills performance. If done right a single plate set up will work for everything you could want on the street. I'd go with a sprung disc as it reduces the shock loads when shifting...makes driving a LOT easier. Badger

[rsimoes]

Originally Posted by Stentor

Per your post a few months ago, I thought you already ditched the twin disc clutch?

I did, back then, but my car did not get here until now and the information posted here I just found out now, when I got my paperwork. . .

Do my decision was reinforced. . .

[rsimoes]

Originally Posted by Badger

I'd go with a sprung disc as it reduces the shock loads when shifting...makes driving a LOT easier. Badger

Is that the only difference between the race and non race McLeod clutches?

[Cobrabill]

Wow,it's been a long time since i've seen BS like this.There has been a Mcleod Street twin in my car since 1996 with no issues.

It didn't/doesn't rattle.
I pounded the piss out of it and it still is fine.

How in the hell can a missed shift ruin a clutch?

[Excaliber]

If you wanna go racing get a single plate?

Wait a minute, I thought you got a dual disc BECAUSE you want to go racing???

Whew, is this ever confusing!

[Jac Mac]

Sounds like BS to me, virtually all the symtoms could equally apply to a single plate as well, given the right circumstances.

We had a twin plate that was fitted to the Aussie GT Falcon in the early 70's, if that was simply installed without careful measuring of finger heights etc it was useless, fitted correctly they gave few problems, yes sure it had a few rattles etc, but so did the rest of the car, it was after all as close as you could get to a road/race car at the time- just like cobra's. If you want quiet- no rattles etc then a cobra probably isnt what your looking for.
I dont get it when people use the clutch for engine braking, isnt that what those big shiny round things behind the wheel spokes are for.

Jac Mac

[eschaider]

It is BS! The new Ford GTs use dual disc clutchs for a reason and it is reliability. All the 'it will break if you use it BS' would not set well with the accountants that have to project the warranty expense.

Think about it. This question doesn't take rocket science to solve.

By the way none of the street twins including the GT rattle. The only thing that I hear rattling is particularily small brains in particularily big heads the act like BBs in a box car.

Come on get real ...

[rsimoes]

You can call it BS if you'd like, but I got the warnings from the manufacturer's installation instructions:

email me if you want a copy of these

I am NOT trying to bad mouth anyone, just give you guys a heads up and like I said, "Although I don't know if this is an exaggeration so they don't get sued, it makes me uncomfortable putting one in my car. . . as it sounds to defeat the purpose of having a dual disc clutch. . .

I just thought I would pass this along in case you're considering one. .. . ."

[Stentor]

I read the Ram PDF file to which you provided a link. A few thoughts:

1. Your synopsis of warnings seems a bit out of context (after reading the Ram literature).
2. I suspect that the Ram literature for their single plate clutches has a lot of the same boilerplate verbiage (providing suggestions for "maximizing the life of your clutch").

I am sure the McLeod single plate clutch will work fine for you. However, your "assessment" of and generalizations about twin disc clutches is probably going to rattle some chains on this site.

[392cobra]

I have been running a McLeod Street Twin for 3 years now.I have a small block,so I'm only putting 584 ft. lbs. of torque thru it.
I have not had one problem with it in these 3 years.There are several other guys in the DFW area w/Cobras,small and big block,that haven't had any problems AT ALL either.

Maybe there is a difference between the RAM and McLeod units ???

[Cobrabill]

Now things are becoming clearer.It's a RAM unit.McLeod has none of these issues.And yes,like someone else commented,the warnings have been taken out of context.

It would seem that they are saying that there is more loading on the clutch when you transition from the burn-out box to dry track than when the tires bite off the line and the front end points skyward?That is PURE BS.

The Mcleod units are guarranteed to 9000rpm & 1400 HP.They are also adjustable to lighten the pedal pressure if you are running say .......500 Hp or so.That way both your legs stay the same size.

I ran one of these behind my 455HO GTO and treated it like a red-headed step clutch.No issues-not even a hiccup.

[Woodz428]

No disrespect to the poster, however, if you read any/most of his posts( usually questions) he has a desire to have a Cobra that is as refined as a Lexus. I am sure that you can build one that way....but the raw and un-fettered by government regulations thrill that IS a Cobra will be lost almost certainly. I believe early on when he first posted, someone suggested he get a new Corvette. I'm beginning to think that is probably a good suggestion. I deal with customers regularly that want me to build them a car "just like" they drove in high school. Unfortunately their tastes, and their experiences with newer cars, have changed. They are never happy with it "just like" their old car. I automaticly turn those jobs away now. If it has air bags or ANY govt. mandated crap, I don't want it and won't buy it. Maybe the Auto mfg.'s should get together while their business is sliding down the tubes and insist that the govt. allow them to offer cars without all that crap, as an option. All motorcycles have used multi disc cluch systems for decades ( I think a century to be more precise) with the exception of BMW. They may use them now.

[rsimoes]

Originally Posted by Woodz428

No disrespect to the poster, however, if you read any/most of his posts( usually questions) he has a desire to have a Cobra that is as refined as a Lexus. I am sure that you can build one that way....but the raw and un-fettered by government regulations thrill that IS a Cobra will be lost almost certainly. I believe early on when he first posted, someone suggested he get a new Corvette. I'm beginning to think that is probably a good suggestion. I deal with customers regularly that want me to build them a car "just like" they drove in high school. Unfortunately their tastes, and their experiences with newer cars, have changed. They are never happy with it "just like" their old car. I automaticly turn those jobs away now. If it has air bags or ANY govt. mandated crap, I don't want it and won't buy it. Maybe the Auto mfg.'s should get together while their business is sliding down the tubes and insist that the govt. allow them to offer cars without all that crap, as an option. All motorcycles have used multi disc cluch systems for decades ( I think a century to be more precise) with the exception of BMW. They may use them now.

WoodZ,

You're wrong about me and what I like and just to think I let you influence some of my past decisions. . . what was I thinking. . .

There is no possible way to have a real tech conversation in here.

[Cobrabill]

RSIMOES-you have some what of a point.But your intial posting was a blanket statement and insinuated that ALL twin disc clutches have the issues you described.This is not true.

And despite a slight"desending grade",this has brought relevant info to light.

[Woodz428]

Rob, I give the same level of advice to ALL persons that inquire, without considerations of their particular leanings. Sorry you were offended, but for the record I have said similar/same to some very good friends and relatives. They are still very good friends and, well, the relatives are stuck with me

Originally Posted by rsimoes

WoodZ,

and just to think I let you influence some of my past decisions. . . .

Just for the record, it was not I that suggested that you sell your engine and car and start again with another, that was all your doings. I said.."Make sure that you are getting what you paid for" when you were with a particular engine builder. If your interpretation was to unload everything at a loss and start again, you weren't paying attention. I never did see your comments on WHY you sold the engine and car at a loss, but I may have missed it. There are many, many people here that do talk tech, but when you are not of that technical leaning, it is sometimes hard to grasp what is being discussed.
I read on my mattress tag that it was not to be removed under punishment of law...so I burned the tag.

[rsimoes]

Originally Posted by Woodz428

I never did see your comments on WHY you sold the engine and car at a loss, but I may have missed it.

The reasons are multiple. This is my last post. Any questions for me, email me.