On 9/25/13 6:39 AM, Dave1massey@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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