Quote Originally Posted by oldcorollas
as for air stressign the fan.. nto really possible... the air resistance compared to the strength of the fan is negligible. what is more likely is that the blades died from imbalance and resulting fatigue.. rather than any amount of air resistance....

which direction were you turning the alt? which way was the fan designed to turn?
The motor is east west and turns forwards from memory - clockwise. Same way the wheels go so makes sense for simplistic g/box and minimal powertrain loss.

So alt must have been spinning c/wise... Fan was definitely spinning the wrong way tho. Made a whistle from as low as 2000rpm. The drive ratio was more than likely wrong as i dont think that the gut who did the original mod would have calculated anything, jus took the V belt pulley off and fitted the 4PK from the excel. But i dont think it could have been the out that overspinning was the be all and end all of why it failed.

If i had to guess, id say pulley dia was half that of crank but no less. So assume a generous redline of 7500, i dont reckon i coulda spun it more that 15,000rpm?

I think that vibration of a non-standard mounting barcket, possibly a mm of belt shear, fan not spinning rite?, and overspinning.

It really needed to be seen to be understood. And i didn have any understanding of anything to do with under bonnets when it was first done. But myself & my mate who bought from me it used to get asked if it had a turbo all the time. And driving along innocently (enough) and hearing this god almighty bang as you see this hole explode in your bonnet - in an excel - is something you just cant describe.