[DeTomaso] Clutch Options-long

[cengles at cox.net]

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
>
>
>
>**************************************
>See what's new at http://www.aol.com
>_______________________________________________
>
>Detomaso Forum Managed by POCA
>
>Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>
>DeTomaso mailing list
>DeTomaso at list.realbig.com
>http://list.realbig.com/mailman/listinfo/detomaso