I'm curious about how you have 0.4 ips vibration problem?
Are you sure its the crankshaft?

Sorry, I disagree that automotive people can do a better job.
How many auto shops check the nitriding and heat treatment?

Pistons and rings are not part of crankshaft balance.
Pins bearings?

Kent Felkins
Tulsa



"stol" wrote in message
oups.com...
If it is in an experimental plane then a good auto machine shop can
probably do a better job then most "certified" aircraft shops. You can
check most of the weights, ie; pistons, rings,pins bearings, rods,,
yourself with a good gram scale. If you do get it balanced please post
back here to let us know how far out it was.

Ben.
www.haaspowerair.com


abripl wrote:
Its not much flying time around here in SD with temps averaging 0F.

I got my engine (Franklin 6) apart trying to cure a vibration problem
(0.4 IPS) - not extreme but anoying. Is it OK to balance the crank in a
automobile machine shop or are there some tricky things about aircraft
cranks? I know automobile cranks go to 6000 rpm and my aircraft crank
only goes to about 2800. So auto shops should be able to do a more
precise job?