Crank Pulley Wobble

thegreek

Senior Member
My little 1935(?)
21 stud (unsure of year, but definitely not 1937) has some crank pulley wobble. No history on the engine. Fires up and runs smooth.

I’ve swapped out the pulley with another known to be good pulley because I was hoping this one was just bent, but to no avail. I figured I would consult those far more knowledgeable and experienced before chasing my tail.
 
first, check that the end of the crank is not bent( use a dial indicator) turn the engine over by hand. second, check the diameter of the crank end to be sure it's in spec. off the top of my head seem to be the most likely causes. maybe some time in the past the crank got dropped or the keyway failed allowing the pulley to spin freely. just my 2 cents. tom
 
if it was my problem, i'd hold off on checking the crank, no so much because it's all that difficult, but because a crank is much more likely to crack than bend. and compared to a pulley that's made out of multiple stamped pieces of mild steel there is no comparison with the likelihood of bending rather than cracking when it comes to a forging or a casting. not even close, IMO.

i'd spend time double then triple checking the pulley, it's fitment on the crank, it's woodruff key AND the one that was "known to be good", before fussing with the end of a crank being bent. good luck :)
 
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