[DeTomaso] clutch question (long)

[JDeRyke at aol.com]

In a message dated 7/16/07 7:21:29 PM, secox at prodigy.net writes:

<< My clutch is extremely stiff.  Since this is my first Pantera, I don't 
exactly know what is correct, but even my friends that get in the car remark 
about how stiff the clutch is.  >>

Many Pantera owners and non-Pantera shops have installed racing clutches 
under the misunderstanding that 'the car looks like a powerful racer so it must 
need a racing clutch...' Clutches are rated by the pressure they exert on the 
disc/flywheel, which I've never seen published but which I suspect is around 
1800-2000 lbs for a Pantera. To give you an idea of the difference that makes, 
I've driven two that had 2600-lb clutches and even for an enthusiast, the things 
were not fun to drive, especially in traffic. Recently, I drove a silver 
state car that had Centerforce's new 'heavy-duty' clutch installed (no published 
rating), and it also was far too stiff for street driving. Compounding the 
problem, '71s and early '72s don't have the 'effort-reduction linkage' under the 
dash used on all later cars, which changes the feel of the clutch. It actually 
doesn't lighten the clutch pedal except at the end of the pedal travel so this 
is not a real fix, by the way. Ford spent many $$$ designing the system so 
you could sit at a stoplight with the clutch in- one of the worst ideas ever 
sold to the public IMHO.

There are a couple of ways of lightening up the clutch pedal pressure.  I run 
the OEM clutch but with a Tilton annular hydraulic throwout system. This 
device fits around the nose of the ZF inout shaft & replaces all the linkage 
inside the bellhousing. Its so friction-free that the pedal is very 'soft' to push 
with a stock master cylinder. In contrast, there's so much friction in the 
stock bellcrank throwout system that the pedal feels at least twice as stiff. D 
Quella sells a similar concentric hydraulic throwout for Panteras. It installs 
simply but following the directions to the letter is absolutely critical, and 
any failure requires pulling the ZF to fix. 

Second is to change the clutch itself from a stock 3-finger Long style to a 
diaphragm type such as Centerforce's STANDARD clutch. This one change makes the 
pedal so soft one can almost push it in by hand, but the power-holding 
capability is the same as the OEM unit, using a stock master, slave cylinder & 
throwout. The drawback is, Centerforce clutches use a different bolt pattern and 
bolt size, so you're stuck with either having your stock flywheel redrilled by a 
competent shop or replacing the stock flywheel with Centerforce's complete 
(overpriced) assembly.

Finally, changing friction discs alone will do nothing except reduce your 
throwout disengagement distance and cause clutch drag & ZF synchro wear if its 
done wrong. 

You'll have to decide what you can live with but the final fix will require 
changing some parts of significant cost. Bottom line- unless your Pantera has 
over about 450 horsepower and you track-race it regularly & street-drive it 
seldom, you don't need a racing clutch with the leg discomfort that goes along 
with it. Get rid of the big clutch! My 2¢- J DeRyke
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