Opinions needed on condition of this crank please

[im4duke]

Finally split the case and removed the rods from my 3.3L 930. Was a little surprised to see some seriously scored rod bearings and wear on the mating surfaces of the crank.

Some background:
1986 3.3L 930
39k miles
Ruf boost control knob, multiple owners ---> likely driven hard on the street
bad leakdown test combined with the above led me to rebuild
engine looks to never have been apart
leakdown results found to be caused by bent valve, piston/valve contact
rebuilding with some common upgrades, hope to do most of it myself at a leisurely pace

2 sets of rod bearings have deep grooves along their centerlines. The mating crank surfaces have visible marks that can be felt, but are not deep nor are they consistent around the circumference.

So, I am looking for some guidance on the condition of the crank. What are the chances that it will polish up fine vs need replacement.

Thanks,
Maxx

[88911coupe]

Hey Maxx, Buck here, I came out to your house a couple of summers ago to help disconnect a couple of things.
Can't help on the parts but I just got some stuff back from Zims who did a fine job checking it all out. I got lucky and everything came back in spec so sort of dodged a bullet there.
One thing Wayne's book mentions about cranks is the hardening process is not easy to duplicate so that probably needs to be considerd if anyone does anything to the crank.
Good luck and your car is awesome.

later

[im4duke]

Thanks, Buck. I remember well and have been following your progress too.

If the crank needs anything more than polishing, I will probably seek a replacement option as opposed to grinding, rehardening and using non-std bearings. Hopefully that will not be necessary.

[vmisquez]

You won't know for sure till you have an expert micro-polish the crank. On another note what head studs have you decided to use in your rebuild?

[im4duke]

I have ARPs on the shelf. Considering going to Supertec.