Is my crankshaft machinable?

[BIGBLAZE79]

I spun a rod bearing. (Not due to machining the Crankshaft) My crankshaft has already been machined 0.02 under on the rod journals and 0.01 on the main journals. How far can you go and still be able to get bearings?

If it is not machinable, Should I go OEM, Manley or Eagle?
Do I still need to balance and micro polish a new crank (OEM/Manley?Eagle)?

FYI: Spun rod bearing due to mis-shift into first gear going 70mph.

 

[92AWDHX40]

I would look around for another one a stock one and get the matching bearings. If its new I cant see why you would polish it if its brand new. I would stick with a oem one depending on your goals and budget for a new crank. Lots are of used ones are out there, I kept one just in case, the one I have now has issues.

 

[BogusSVO]

With the Rod journal being .020/.50mm undersized, you are at the end of the cranks life.

Find another stock crank, pull the balls, give it a good clean, and polish or grind as needed.

 

[BIGBLAZE79]

Thanks Dale and iugrad92turbo,

I want to buy a new crankshaft then. I know OEM is good but are they plug and play? I'm taking my head, block, pistons, rods, harmonic damper and fly wheel to the machine shop. Should I have all the rotating assembly balanced with the new crank? Should I have them do any checks for straightness or micro bead polish the new crank?

 

[BogusSVO]

If you are a stock rod build, the used factory crank will be balanced to factory specs, so yes that will drop in and go.

If you have a H beam/forged piston set up you may want to have it all balanced again.

I would suggest that the rod that spun, or better yet all of them, have the big ends checked to make sure they are still round and in spec.

High to low spec is .0007 on the housing bore.


If you go aftermarket crank, make sure to have it balanced, I would also mic all the journals to verify that they are in spec. They should be, but it better to know than to assume.

 

[Fotowntalon]

You can always get the crank welded up and machined to specs, anything can be repaired with enough money. =) But do to the cost of something like that, you would be best getting a replacement.

 

[crash89]

If Im not mistaken, wouldnt a mis shift like that float a valve or damage pistons/bend rods before it would spin a bearing? Doesnt seem like the cause of the failure to me..

However these guys pretty much covered everything else!