[gto_ron]

My local machine shop called today and said my crankshaft(389 Pontiac) was cracked. I realize a crack is undesirable but is the crankshaft junk? Are cracks that common in cranks?

thanks for any and all responses

Ron

[ericnova72]

Yep, it is junk, it's just about the worst piece to have a crack in it. Connecting rod crack would be about the worst. Yes, it is a common piece to find cracks in, and be glad you found it now and not at 5500 rpm.

[kleen56]

Its not that common but it does occur. Mostly, what is called heat cracks. Either the engine was lacking lubrication to the crank and bearing or it ran hard and overheated the metal causing cracks to the surface. Unfortunately you need to replace the crank with a good one.

[WDCreech]

With the price of good cranks, for Pontiacs, out there, You should be able to get a good casting for under $300, or a forged one for about $500. I recently bought a 4.25" stroke, 3" main Scat forged unit, for $500, new.