Posted by Matt Wilson on Friday, August 27, 2004 at 6:49PM :
In Reply to: Re: 0.040" undersize crank in 230? posted by Vaughn on Thursday, August 26, 2004 at 9:37PM :
I would caution anyone wanting to nitride their crankshaft. I took my 230 crank to a shop that has nitrided hundreds, if not thousands of cranks over the years, but most of those are V8's. When they did mine, it warped ever so slightly. So slightly, in fact, that it's undetectable when doing the standard runout test with a dial indicator and two v-block supports. However, when you support it in all four of the main bearing journals, you can detect the runout with the dial indicator, and it binds in the bearing bores of the block when the bearing caps are part way tightened down. It's not a problem with the engine block, as other crankshafts work fine. It's a problem with the nitrided crankshaft. My machinist had warned me about that, but I didn't listen. I tried to get it straightened at two different machine shops, but it's pretty much impossible to correct such a small amount of warpage. I ended up buying another crankshaft and I did NOT nitride it this time.
Just my cautionary note to anyone thinking of doing this. If anyone else has had good luck nitriding a straight 6 crankshaft, I'd be interested to hear about it.
Matt
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