Thanks for the interesting breakfast read Michael.
You don't mention much about vibration dampers, particularly tuned vs
non-tuned. The factory rubber-bonded style damper only works correctly
on the engine it came off as it can only damp one specific frequency.
There are a host of aftermarket designs that use viscous fluid or
'rattler' pucks to achieve damping at any frequency and regardless of
engine type. I believe guys are even making them to go on the flywheel
to damp vibes at both ends. For a relatively simple piece of
engineering, their prices seem to be based on "it is still cheaper
than a blown up engine".
Another thing that doesn't get much mention and is a direct result of
crankshaft torsional flex is timing scatter. The vibrations find their
way through the cam chain and into the distributor where they react
with the flyweights and other parts so the timing, and equally
importantly the dwell can vary wildly at high rpm. I heard that some
Chrysler V engines with the distributor at the back will explode the
flyweights if fitted with a gear drive cam since the chain dampens out
a fair amount of vibration. The BMC six cylinder timing marks will
scatter around an inch or so at high speed, more when suddenly closing
the throttle as this is where the most crankshaft stress occurs.
Andy.
On 1/4/17, Michael Salter <michaelsalter at gmail.com> wrote:
> New post on my blog about Austin Healey 100 crankshafts...
> <http://www.netbug.net/blogmichael/2017/01/03/austin-healey-100-crank-failures/>
>
> ?M
> ?ichael S
> BN1 #174?
>
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