Attached Link: http://www.baument.com/restore/archives.html

How accurate does it have to be - will something vaguely engine-y do, or does it have to satisfy a WWII U-boat nut in every detail? :)

There are a few generators and such-like scattered about, and if that might do the job I'll hunt one out. Baumgarten has some industrial stuff in 3DS format if 'vaguely engine-y' is good enough.