Dave Massey wrote:
> How different (if any) are these rids from those used in the
> GT6? Some folks tune GT6 motors to turn 7K with good
> results. But then it is a shorter stroke. Which begs the
> question "what is the stroke of the Ducati?" (remember the
> TR6 has a rather long stroke)
>
> Dave
Dave, the GT6 is the same exact rod that the TR6 uses (as well as MK4 and
1500 Spitfires). You are right, there are even GT6 motors that turn 8K
without hesitation, Kastner acknowledges this in some of his writings. The
stroke is different and the wrist pin location in the GT6 piston is also
different.
Again, I think the biggest contributor to problems people have with wear and
breakage of bearings and rods in TR6 motors is because of the extreme
angularity that occurs when the crank is at 90 degrees (or 270 degrees) for
a particular cylinder. The rod / stroke ratio of the TR6 is down near
1.53:1 while most modern (4valve/cyl) motors are around 1.75:1 (and some
Ferrari and Mercedes motors fall dead on this figure). The GT6 by
comparison is around 1.92:1, which is just short of "ideal" for a two valve
motor. David Vizard has written he likes to see it closer to 2.1:1 for two
valve motors.
I am a big fan of the GT6 motor, so much so I have considered destroking my
TR6 motor down to GT6 specs.
Kai
1972 TR6 CC77896L
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