[TR] Harmonic Balancer for TR-4?

[Randall]

> Others, however, think I 
> should upgrade to a harmonic balancer.

IMO it depends on your intended usage.  For street operation at normal rpm,
IMO the "balancer" (which is a misnomer, it's really a harmonic vibration
damper) is not required.  I've run my street TR3A that way for almost 20
years, and the only problems related to it were because I didn't use Rick's
kit.

OTOH if you plan to spend much time at all above 5200 rpm or so, then it's
probably cheap insurance.  There is supposedly a resonance point up there
somewhere, where the harmonic vibrations will build up and cause extra
stress in the crank.  Those vibrations combined with the much higher forces
at high rpm (plus higher output from a heavily modified motor) can and do
cause crankshafts to break.

> If I decide to go to a 
> harmonic balancer how do I find one to fit?  Does anyone on 
> the list know of a direct fit harmonic balancer for the TR-4? 

Dampers are available from most of the vintage race suppliers.  One source
is British Frame and Engine http://www.britishframeandengine.com

It's also possible to use the dampener from a MGB, but requires a spacer and
special seal to do so.  And it's not clear how well the MG dampener meets
the needs of the TRactor motor.

> What issues should I 
> expect in converting?  

All of the dampers I know of require converting to a narrow fan belt.  That
means a different water pump pulley (and a water pump where the pulley is
removable, some aftermarket pumps are not).  Also a different pulley for the
generator or alternator.  Not difficult issues of course, just more things
to be dealt with.

Randall