[DeTomaso] Hot Rod To The Rescue - A 351 Cleveland Is

David Nunn dnunn at telus.net
Thu Jan 19 12:44:39 EST 2017


Julian & Mike, 
I have a Tri-Tec composite gear in my Pantera's engine and will report back
here, regarding it's durability. I admit I'm nervous because when you hold a
composite gear in your hand, it feels like it's made of plastic. 
Here's where you need to be careful (aside from making sure the gear is
installed at the correct height) and this doesn't only apply to composite
gears, although it's more critical with composite gears: make sure the
interference fit between your distributor shaft and the ID of the gear is
correct. The gear should be a press fit onto the shaft. You should not be
able to just push it on by hand! With a composite gear, it's also bad if the
press fit is too tight. 
Tri-Tec told me when they started on the 351C composite gear project, they
purchased a bunch of 351C distributors and gears to take measurements. They
were shocked by the variations in shaft diameters and gear ID's. In one case
they drove out the pin and the gear just fell off the shaft (Mallory)!
Accordingly, Tri-Tec based their dimensions directly off of the original
Ford blueprints. Tri-Tec speculated that some 351C gear failures were
probably caused by gears being too loose on the distributor shaft. Tri-Tec
also makes 351C gears with an undersized ID, so you can have a machine shop
hone it to the perfect ID for your distributor, if you feel the shaft is
undersized. NASCAR teams all buy them like that. You can't buy them like
that on-line. You need to call and ask for one. Also, with composite gears,
you can only drill one hole through them. You can't turn them 90 degrees and
drill another hole, like you can with a steel, iron or bronze gear. 
David  
-------------- next part --------------
   Julian & Mike,

   I have a Tri-Tec composite gear in my Pantera's engine and will report
   back here, regarding it's durability. I admit I'm nervous because when
   you hold a composite gear in your hand, it feels like it's made of
   plastic.

   Here's where you need to be careful (aside from making sure the gear is
   installed at the correct height) and this doesn't only apply to
   composite gears, although it's more critical with composite gears: make
   sure the interference fit between your distributor shaft and the ID of
   the gear is correct. The gear should be a press fit onto the shaft. You
   should not be able to just push it on by hand! With a composite gear,
   it's also bad if the press fit is too tight.

   Tri-Tec told me when they started on the 351C composite gear project,
   they purchased a bunch of 351C distributors and gears to take
   measurements. They were shocked by the variations in shaft diameters
   and gear ID's. In one case they drove out the pin and the gear just
   fell off the shaft (Mallory)! Accordingly, Tri-Tec based their
   dimensions directly off of the original Ford blueprints. Tri-Tec
   speculated that some 351C gear failures were probably caused by gears
   being too loose on the distributor shaft. Tri-Tec also makes 351C gears
   with an undersized ID, so you can have a machine shop hone it to the
   perfect ID for your distributor, if you feel the shaft is undersized.
   NASCAR teams all buy them like that. You can't buy them like that
   on-line. You need to call and ask for one. Also, with composite gears,
   you can only drill one hole through them. You can't turn them 90
   degrees and drill another hole, like you can with a steel, iron or
   bronze gear.

   David


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