Dual Disc clutch

quote:

Originally posted by shelby racer:
Has anyone got the PN#s for a McLeod dual Disc assembly and Hydraulic throw out bearing?

The pictures in the thread are dead (photobucket fiasco)

http://pantera.infopop.cc/eve/...251005856#6251005856

.....but the link to the slide show JFB posted is still alive.

https://www.slideshare.net/Jos...throw-out-bearing-zf

Best,
Kelly

Kelly's install is pretty great, but it looks like quite the project.

I am happy with a Centerforce Clutch, and the "traditional" McLeod throwout bearing.

I guess it all depends on your HP & driving style, though (and pocketbook, and free time available).

Rocky

quote:

Originally posted by Rocky:
JFB's install is pretty great, but it looks like quite the project.

I am happy with a Centerforce Clutch, and the "traditional" McLeod throwout bearing.

I guess it all depends on your HP & driving style, though (and pocketbook, and free time available).

Rocky

That was my install and write up. JFB just made the file publicly available because I couldn't post the pdf here. The OP was asking about those two specific parts. It was as much of a cautionary tale for anyone thinking about buying what McLeod was calling a Pantera specific throw out bearing "kit".

On the subject of clutch selection though, if you don't need the extra torque holding capacity, really no need to spend the extra dough on a dual disc. Some might even argue less is better because a little slip can limit load spikes and provide a degree of protection to the zf. Others might say that's what the clutch and gas pedal are for.

The type of slave is really just personal preference. Internal slaves have a clean appearance but when they fail, they do so inside the bell, can deposit oil on your clutch, and are a lot of work to repair since you must pull the TA/Engine. The external slaves are easy and the ZF is already set up with the cross shaft. They both do the job. That was my first and only such TB install on a zf. Wont happen again.

Best,
Kelly

To add to what has been said, in the case of a ZF, if you need a dual disc clutch to handle the increased engine power, then likely you are over the power handling capacity of the ZF?

You really want a fuseable link. You want the failure to happen before it gets to the ZF.

A dual friction disc is probably what you want to go with.



I can't think of one car that I have driven that I can't make the clutch slip momentarily on including the dual friction. In fact that thing when new is freaky with it's herky-jerky locking/slipping tendency.

CF will tell you to expect a 500 mile break in period but that doesn't help you in a race car where 500 miles might be on the next engine rebuild? It definitely can be made to slip very easily until broken in.

The thing will in fact cut itself into the face of the flywheel. You can catch you finger nail on the groove. Probably goes as deep as .010"?



Many of my "advisors" are drag racers. Many chimed in with me that the CF DF was good to about 800hp. These guys are using nitrous around 200 to 300 hp of it.



You need linings that are not going to glaze and a flywheel that is not going to react by creating high spots on the surface. Lots of people like the McCleod but that's almost because they are the only ones left building any kind of clutch for a "performance car".

The clutch disc IS the fuseable link. You can not re-engineer the car to the extent of changing that.



If the driver can't handle the equipment well enough to be competitive, change the driver.

If you want to re-engineer the car, consider putting in a Porsche PDK type transmission where the driver becomes the monkey that merely points the car in the right direction.

Power handling isn't the only reason to use a dual disc clutch. The BMW M1 used a dual disc clutch with a ZF transaxle. They did it in order to make the bell housing as small as possible, so they could mount the drivetrain as low as possible but still have reasonable clamping force and good ground clearance. I believe the discs were about 8" in diameter. Using a small diameter flywheel and clutch also reduces the moment of inertia, so the engine will rev more easily.

My biggest problem with a dual-disc clutch in a Pantera is the stock car's marginal clutch disengagement distance, and two discs only make this worse. We NEED an absolute minimum of 0.040" clearance space between the flywheel and the clutch disc, as measured by inserting a feeler gauge thru the ventilation hole in the bellhousing. This amount of course means only 0.020" disengagement clearance between BOTH sides of ONE disc, IF the clutch pedal is matted between shifts. Which no one does.

The math is not hard to extrapolate this amount of space for two discs and both sides of a floater plate. Extra clutch drag means extra ZF synchro wear between shifts and a shorter life for this complicated and increasingly expensive repair.

Since the Byars boys & others had no problem with a single disc in their massive torque BBF & BBC Pantera conversions, and IRS cars of all brands make poor drag racers unless very highly modified, I'm left with doughnut-shoppe-bragging-rights as the main value of dual-disc Pantera clutches.

Occam's razor.

Simpler is better. In this case a single disc is as good as a dual disc.