[TR] TR3 Crank

[Don Hiscock]

...and a guy *seriously* rallying a well-known TR4 in the UK with a
*very* tuned engine uses an 8100 rpm redline, IIRC.

These aren't normal production engines anymore, though!



On 9/25/13, TeriAnn J. Wakeman <tjwakeman at gmail.com> wrote:
> 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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