Pressure plate "bob weight" query

Peter,

I run a centre force clutch with the bob weights. No problem in 40,000 Kms.

Doug M

It is a known problem with some installations.

It is not a problem with other installations.

As the clutch disk wears and becomes thinner, the three fingers move closer to the flywheel as the counterweights move away from the flywheel – closer to the bell housing. Thus, the counterweights that do not see interference at initial installation may at some later date start to hit the bell housing.

The gamble is yours.

Larry

Std bob-weights on a 11" Long clutch WILL hit the ribs cast inside Pantera bell housings. The factory found this out in 1970. Exceptions are:

A- Centrifugal clutches that use flat sliding weights instead of bob-weights on pivoting rockerarms. Centerforce-type are sliding wts.

B- 10" or 10.5" SBF clutches with small bob-weights MAY clear the inner ribs. The article assumed a stock 11" Long-style clutch.

C- Someone already tried it in that bellhousing and pre-smashed clearance in the structural ribs.

I was going to ask about milling clearance...

The problem is, almost no one realizes just how small the 98" wheelbase Pantera actually is! Every dimension possible was shaved down to cram a std, unaltered 351-C longitudinally into a too-small engine bay. That's why we have a 'shrink-wrapped clutch'. Ford seemed to be worried about halfshaft u-joint angularity which drove all this space-optimizing. But as it turned out, the dozens of hot-rod big-block adaptions (at least 3 varieties) in the years since- which are mostly shoved backwards up to 4 full inches from 'stock', show their concern re reliability was mostly unnecessary.

quote:

Originally posted by Bosswrench:..Ford seemed to be worried about halfshaft u-joint angularity which drove all this space-optimizing. But as it turned out, the dozens of hot-rod big-block adaptions (at least 3 varieties) in the years since- which are mostly shoved backwards up to 4 full inches from 'stock', show their concern re reliability was mostly unnecessary.

"there is theoretical and then there is real world" (where have I heard that before)

Considering how Ford made ZF modify this unit to the point it became the -2, if this was any kind of not even a big deal, they would have made ZF modify the bell in order to use the regular Mustang clutch with the counter weights on it?

The gearing on the -1 makes it really the preferred transmission for the car.

The 2.42 first gear is a much better ratio than the 2.20 GM ish ratio in the -2.

There are those unknowing Pantera owners who installed the Mustang clutch and lucked out with the counter weights cutting themselves clearances inside the bell without destroying everything.

I shudder to think of it but when you remove all of the obvious, whatever remains no matter how seemingly impossible, must in fact be the answer?

Here is a picture of a Pantera Clutch and the proximity of the (reduced) counterweights to the bell housing stud bosses.

It's pretty tight in there!

Rocky

Lest someone suggest I am running a Mustang clutch....

Model 11CF, baby!

Rocky, the OEM DeTomaso clutch lever arms had the entire loop cut off each of the 3 levers. That clutch still has the loops where bob-weights are bolted on. Things expand quite a bit when the bellhousing, clutch and ZF get 'warm'. You could make things a little safer in there by using a grinder to the exposed loops, without noticably changing the clutches' balance.

Another not-so-good thing the innovative among us sometimes did was to substitute hex-bolts for the two metric allens used inside the dash-2 bellhousing to bolt up the ZF. That also can cause metal-to-metal contact.

Pantera OEM pressure plate.

John

This's is getting really interesting.

This is fascinating.

This clutch is an 11CF, with a DeTomaso Isis in it.

It was originally installed in July 1990, and ran in the car for ~ 40K miles without incident.

I can't explain the bob-weight mounting fixtures. I am pretty sure that there was no disassembly / modification of the clutch assembly. I believe it was installed by one of the major SOCAL vendors. That's how my PO rolled.

I'll let you know if I find anything after more investigation of the receipts.

Rocky

My pressure plate displays the same de Tommaso Isis and part number as Rocky's pressure plate. It also has the same bob-weights as Rocky's pressure plate. I have always been led to believe it was original to 2511. I have had it locally rebuilt twice in my 50,000 miles of ownership and it never had any issues transmitting approximately 300 RWHP. It did obviously wear out and require rebuilding, but it was up to the task for which it was designed.

Larry

I suspect that the difference might be between -1 and -2 bellhousings.

Mine (bob weights removed) is from a -1.

Chuck and Larry's are from a -2.

John