Checking a Crank??

ok i hope nobody hurts themselves laughing at me for asking this...

but does anybody know anything about 'bouncing', 'ringing', or 'sounding' a crankshaft for cracks? honestly i'm not sure what the hell to call it! my machinist is an old timer and checks crankshafts by 'bouncing' them on the floor of his shop. he just bounces the crank on the concrete floor in an upright position from about an inch or two off the ground... this of course makes the crank 'ring'. and by the sound he can tell if there is a crack in the crankshaft.

is this something that a lot of machinist do? i think he's a freakin' wizard! and he is always right! thanks... sean

www.metalmafiaracing.com

 

This absolutely works, but requires experience. The problem is that it will find a crank that is already "dead", but will not find the cracks that are just starting and give you an idea of how much longer a crank may last. This takes a wet 'flux with a black light. Most blown alcohol cranks start to show cracks early in their life, and it is interesting to see them progress.

 

I guess that works but,I always check mine with crach check dye.You paint it read with the penetrant and let it dry then clean it and paint it with the developer and it will show even the smallest cracks.Your local welding shop can get you the stuff.