Very useful info, as always. Was wondering how much 'de-stroking' the
engine--shorter piston/rod thows--would help? Of course, you'd need to
source yet another type of crankshaft, conrods, etc..
Bob
On 1/3/2017 1:23 PM, Austin Healeys List wrote:
> 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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