[TR] TR3 Crank

TeriAnn J. Wakeman tjwakeman at gmail.com
Wed Sep 25 08:38:10 MDT 2013


On 9/25/13 6:39 AM, Dave1massey at cs.com wrote:
>
> I don't know what caused it but I've heard that even the factory cars had
> problems over 5,000.
>
>
The TR3/4 crank has a major harmonic around 5200 RPM that tends to break 
the crank at the base of the flywheel mounting flange.  There is a 
second major harmonic a little above 6200 RPM that tends to break the 
stock crank in the middle.  This is why the TR engine is factory 
redlined at 5000 RPM.  The harmonics can shift a little along the RPM 
spectrum if the crank, rods, pistons & flywheel are not balanced.

The aftermarket harmonic balancer sold the the TR engines tames the 5200 
RPM harmonic.  It requires going to a narrow fan belt & an electric fan.

My engine is balanced, has a nitrided stock crank and a harmonic 
balancer. It sees 6000 RPM under full acceleration.

TeriAnn


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