Crank pulley balancing after trigger wheel fitment
Turbo Mini Forums

I have recentley fitted a 36-1 trigger wheel to a standard harmonic damper pulley by means of machining a 7.8 mm deep step on to which the 8mm thick trigger wheel fits. The trigger wheel is of this type: http://cgi.ebay.co.uk/Trigger-wheel-5-75-r...=item335a16fef2

Two hex head bolts are then threaded in to holes that were drilled and tapped near the edge of the damper pulley.

My question is does the pulley now need balancing again? How do people ussualy attach this type of pulley to the standard damper?

Thanks
Andy

Edited by adcyork on 7th Mar, 2010.

Well, I would say don't affix anything to the outer segment of a damper pulley wheel as this moves indepenently to the hub (& therefore crankshaft) of the crankshaft pulley.

Some folks machine trigger wheel teeth into the outer segment of the damper pulley wheel which is also erroneous as it moves independently to the hub/crankshaft.

The outer segment moving indepenedntly to the crankshaft can cause ignition timing 'scatter' by 5 degrees on a good day so it's better to fix the trigger wheel solidly to the crankshaft by using a KAD trigger wheel kit, the kit includes a trigger wheel hub which is bolted directly to the crankshaft which eliminates any chance of ignition scatter.

Make sure when it's all fixed in place that there is a gap between the trigger wheel & the outer segment of the damper pulley wheel to allow movement of the outer segment.

Many people have done what you have done, either machined the the damper directly or fitted a wheel. I don't know of anybody having timing issues, despite the fact that the damper probably does move a bit.

As for ballance, again nobody has reported real problems, but if you wanted to ballance it you could.

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The damper does move but the scatter this creates is very low and not worth worrying about.

I always had my pulleys (ones I used or sold) rebalanced after machining....

Alex

AlexF