CorvAircraft> Nitriding and a few dumb motor questions

[jbfjr]

Jed,

I'm in the process of building up a Corvair engine per the WW 
manual, and a few weeks ago I spent a couple of hours with a guy 
who grinds cranks for a living.  Unfortunately after magnafluxing 
my crankshaft he found two small cracks on the No. 6 journal which 
of course rendered it useless to me.  Had I been able to use it, 
he recommended cutting about 0.008" off of the crank and then have 
it nitrided.  After nitriding, he then recommended cutting an 
additional 0.002" thus yielding a 0.010" ground and hardened 
crankshaft.  I don't know what WW's opinion on this method is but 
I believe Mark Langford recommends a similar method.  The 
crankshaft guy said it was his opinion that the nitriding process 
usually introduces a very slight mis-alignment of the crank due to 
the fact that it is laying flat while being heated to 900-1000 
degrees F.

I've also heard that the nitriding process will require you to tap 
out the safety shaft threads, assuming you have already drilled 
and tapped it.

FWIW, but remember I'm no expert!

Regards,
John Franklin
GN-1 Aircamper
164cid Corvair
Richmond, TX 

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