[DeTomaso] Clutch Options-long

[cengles at cox.net]

Dear Paul and Larry,

So.....for the remedial student: shaving the throwout bearing will not help the problem. There is not any *other* bearing easily accessible part or bearing in the bellhousing that could be modified to help the problem. Paraphrased, again, if there was *any* easy modification to be performed inside the ZF bellhousing, then some inventive Panterahead would have done it and publicized it by now, right?

Thanks, Chuck Engles



---- Paul - Home <thedrol at pobox.com> wrote:
>This won't get you more clutch disengagement (the 0.040" that Jack is
>talking about). This can give you more free play before the throwout
>bearing hits the clutch. But you can also get this same (throwout
>bearing to clutch) clearance by properly adjusting the slave cylinder
>and the stop.
>
>Paul
>#9270
>
>cengles at cox.net wrote:
>>Dear Jack,
>>
>>Dumb question: I have been told that one *could* take the throwout bearing (I think that's right....) and have a machinist remove .030" off of it. This is supposed to a) have no detremental effect on the bearing and b) provide extra clutch-flywheel disengagement room, perhaps in excess of .050-.060". Is that true? Seems like an attractive modification, so there must be some downside to it.
>>
>>Easily fooled, Chuck Engles
>>
>>
>>
>>---- JDeRyke at aol.com wrote:
>>>The DeTomaso bellhousing fits so closely around the flywheel & clutch that
>>>ANY clutch you use should be checked for protrusions before bolting it on. The
>>>3-finger Long clutch cannot have centrifugal bob-weights on the levers or they
>>>will crash into and break the cast inner bellhousing braces on the 1st
>>>revolution of the engine. All Mustang clutches have bob-weights. Centerforce
>>>diaphragm clutches don't have protrusions but fit close enough that a snap-in plastic
>>>cover on the upper vent hole will not stay in place.
>>>
>>>Centerforce clutches use 3/8" dia shoulder-bolts-with stand-offs, and a stock
>>>flywheel is tapped 5/16", so either a new flywheel is needed with
>>>Centerforces or a good machinest to retap your old flywheel. Using 5/16" bolts in 3/8"
>>>holes guarantees a sloppy fit and vibration. Using 3/8" shoulder bolts with no
>>>stand-offs will leave the clutch loose on the flywheel with the bolts tight.
>>>Finally, there are several bolt patterns possible with various clutches, and
>>>redrilling/retapping a flywheel correctly is tricky. Some aftermarket flywheels
>>>have several patterns drilled & tapped but the hole diameters needed also vary.
>>>
>>>Third, once you've assembled everything, the disengagement distance at the
>>>flywheel (with clutch pedal flat to the floor) must be at least 0.040" as
>>>measured with a feeler gauge thru the access hole in the bellhousing (engine OFF).
>>>This means that disc is only 0.020" clear of both flywheel and clutch, which is
>>>not really enough but is the best we can do in a Pantera with all-new stock
>>>parts.
>>>
>>>A too-thick clutch disc will make it all but impossible to get any release at
>>>all. A long-throw slave cylinder will increase the disengagement measurement
>>>a bit. Worn over-center linkage under the dash (L-models only) will reduce the
>>>disengagement distance, as will a sloppy fit of the slave in its bracket on
>>>the bellhousing, or a master cylinder that internally bypssses pressure. All
>>>this effort is to prevent extra clutch drag and wear while shifting your
>>>expensive 35-year-old ZF synchros.
>>>
>>>You will likely need to readjust the lever at the bottom of the slave
>>>cylinder one or more splines on the shaft going into the bell housing, in order to
>>>prevent the throwout bearing from constantly riding on the clutch. When you do
>>>this, its possible for the lever to hit the bellhousing in an area not easily
>>>visible. Unless the bearing is a constant-contact type, it will quickly wear
>>>out if there's no free play- also wearing out the clutch fingers on either type
>>>of clutch. Because replacing the throwout or pilot bushing is such a chore in
>>>a Pantera, I advise replacing them anytime the bellhousing is removed.
>>>
>>>When replacing the pilot bushing inside the crank, check it first with a
>>>magnet. Many "bronze" bushings these days have iron filings in them to make them
>>>cheaper, and such a bushing will wear the ZF shaft nose, as will a roller
>>>bearing if it siezes 6 months later
>>>
>>>Unless you've done this stuff before, or are an excellent trouble-shooter
>>>with lots of spare time, I really advise you to buy a whole package from one of
>>>the vendors, rather than trying to piece something together from the hot-rod
>>>shops that may save you $15 initially but cause $eriou$ problems later. With a
>>>vendor, when things go wrong you've at least got someone to call for answers or
>>>warranty claims. IMHO, this is NOT a simple job; good luck- J DeRyke
>>>
>>>
>>>
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