Porsche 930 Engine rebuild

[ady930]

Hi Guys

I need to rebuild my 930 engine. Lots of info but require good advice. Firstly need to know if a person grinds the crank to the first phase does one then have to re nitride it.

Ta

Adrian

[David]

If your crank has a bad journal, it would probably be easier and cheaper to find another crank.

If your just getting the journals polished, hardly any material will be removed so re-nitriding would not be needed.

[AFM744]

Can you be more specific about your "rebuild" needs? Did something go boom? Is it burning a lot of oil?
Many of us here have rebuilt our engines and if there's one common strength about our engines, it's the crank. If you spun a rod bearing on it then you'll need to get it ground, or as David advised, just find another. Otherwise, my crank had 90k on it and came out of the engine in perfect shape, so I didn't do a thing to it.
Weak points on the 3.3;
valve guides wear out. I think the consensus on this forum is that if they're OEM guides they're worn out. Bad things can result from this.
Rod bolts can fail if overrevved; replace with ARP.
Head studs break; replace with ARP, Raceware, Supertech, the flavor of the month is 993 Turbo Dilavars ($$$$).

[fredmeister]

Just read in Wayne's book on rebuilding 911 engines that you're better off getting another used crank in good condition that is still nitrided. If you machine your damaged crank you loose the nitirde and the process no longer exists to redo it properly.
Just my opinion. Call a few machine shops that specialize in Porsche and get their opinion too.
Fred

[boostfix]

I didn't know what nitriding was and found this great explanation on a steel site:
http://steel.keytometals.com/Articles/Art117.htm

[nocarrier]

Cool site detailing the nitriding process!!

Just for fun I googled crankshaft nitriding and found a couple of companies that sill do this hardening process.

I wonder if they could do a 930 crank?