At 12:14 AM -0500 11/8/96, Chip Old wrote:
>On Thu, 7 Nov 1996, Stuart Bollen wrote:
>
>> John, I installed a Spitfire fan and it works great. My only concern is
>> that someone told me the original fan acts as a crankshaft damper
>> because of its weight, and a plastic fan could cause the crank to break
>> at high RPM. Anyone got any comments about this?.
>
>I've had a plastic TR6 fan on my TR4 for years, and the crank is still in
>one piece.
Still, the problem is real. TR234 cranks have a nasty harmonic vibration
which sets in a few hundred RPM above the redline. On occasion, they
break...
>From what I've heard, it's very rare for a fanless crank to break if the
RPM limit is strictly observed. But if you don't like that idea, you can
add a harmonic damper. There are a couple of options; you might try British
Frame and Engine for up-to-date info..
-john w.
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