[TR] fan extension, fan belt, steering rack

Randall tr3driver at ca.rr.com
Sat Sep 1 12:03:56 MDT 2007


>	Pardon my ignorance, but I have a question. Do the eliminated parts
contribute in any way to balancing or
> dampening vibrations on the crankshaft?

On the TR2-4; I've been told by those who should know that the stock fan
itself, and the rubber bushings it mounts on, acts as a harmonic dampener.
This has nothing to do with engine balance (although the fan assembly is
balanced by itself), but with reducing vibrations in the crankshaft that add
to it's stress.

However, based both on personal experience and what I've been told, this
doesn't appear to be too important for nearly stock, street-driven engines.
It's the people who consistently run over 5000 rpm that seem to need the
dampening.  To that end, most of the racing TR parts suppliers offer a
harmonic dampener to fit the TRactor motor.  It's also usually alloy, and
usually part of a narrow belt conversion, and quite pricey.  TriumphTune
used to sell the parts to allow using the dampener from a BMC motor, but
AFAIK that kit has been NLA for a long time.

I've run over 100,000 miles on the street with no mechanical fan or
extension, even exceeding 5000 rpm on occasion (once had a passenger ask me
if the tach was supposed to hit the stop like that <g>), and never broken a
crank.  I have seen the cranks others broke, but AFAIK every one of them was
on the race track, not on the street.  YMMV of course.

Randall


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