Just another word about the crankshaft dampers on the Tiumph 6 cylinder
engines. This
applies in particular to the TR-6 engines Due to the torsional vibration the
front
damper sometimes will have the outer ring (which has the TDC timing mark on it)
move
as much as several degrees. This gives a retarded position for the timing
mark and
you will have a power loss and the engine really feel lazy and slow to rev. It
is
worth checking or better yet do as I did and mark the inner part to the outer
part with
a sharp line so that you can check each time you go over the engine tune. I
finally
drilled a 1/8" hole in the bottom of the belt groove right through both parts
of the
damper. Before & after each practice session or race I would check the damper
by
sliding a 1/8" drill into the drilled hole to make certain that the parts were
still in
alignment.
R. KASTNER wrote:
> As I remember ther was no difference in materials between the early and late
>cranks
> but, the later parts are cross drilled on the rod throws and thus a much
>better
> part.. Nitride hardening the crank will give about a 50% increase in strength.
> There is a little system to follow in doing this and if you actually intend
>to do
> this contact me and I'll fill you in on how I did (for years). If you are not
>going
> to spin the motor don't bother with the effort.
> Kas Kastner
> Bob Lang wrote:
>
> > Hi All...
> >
> > Great topic.
> >
> > I have a question though, and I suspect Mr. K can provide some insight.
> >
> > Early TR6's use a different crank than the later ones, I have no idea
> > what the cutover engine number was, but I suspect it was CC50000... at
> > any rate, folks refer to this crank as a "long snout" unit.
> >
> > The question is, is a long snout crank inherently any better or worse for
> > one of the mega RPM applications? Or does it matter?
> >
> > I was told by a TR250 Autoxer named Jeff Janick that long snout cranks
> > are better, and then subsequently realized that they are also made from
> > "unobtainium" when I started to look for one. As luck would have it, at
> > least one of these has become part of my "collection", and I figured it
> > would be nice to know this info for the inevitable "phase two" motor that
> > I'll probably be building in the next calendar year or so.
> >
> > Wow. 8000 RPMs with a TR6 motor. Koool!
> >
> > rml
> >
>-------------------------------------------------------------------------------
> > Bob Lang Room N42-140Q | This space for rent.
> > Consultant MIT Computer Services |
> > Voice: (617)253-7438 FAX: (617)258-9535 |
> >
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