Custom main bearing spacers?

[Blaze]

Anyone know anyone who can custom make bearing spacers for main bearings? I have a forged Pontiac 317 crank that I want to put into a Pontiac 400 block. The 317 is a 2.5" journal crank and the 400 is a 3" journal.

 

[zuke]

That would be an almost 13mm undersized bearing, since bearings are soft by design, I think they'd wear out pretty quick... You'd probably want some kind of hard steel spacers, and then regular 2.5 inch bearings... Just spit balling that though, I have no experience dealing with that big a gap.

 

[a_kelley]

You could I suppose get some spacers made that have a lip/lock tab like the bearing does on the backing and made to accept a bearing on the inside, and drilled for oil feed. it would have to be a tight tolerance part obviously. I don't see why it's not possible, just it would be expensive... On another note, what about a custom crank instead? May be cheaper and more available..


By the power of gargoyle, may I present Pontiac Street Performance - Bearing Spacers For 3" Journal Crank in 3.25" ? .. it says "nunzi" & "program engineering" sells what you seek.

 

[Fabrik8]

A new forged crank with the proper journal size is probably $700, plus or minus $100. I'm not seeing the value of reusing the undersized crank by the time you find/buy some custom spacers, get any welding done, final machining, etc. Everyone makes a 3" crank for a 400 block, so that's the easy option, and you'll never have to worry about anything related to the bearing spacers going wrong.

Am I missing something here? Is the forged 317 crank some super-rare, high dollar part?

 

[Blaze]

You could I suppose get some spacers made that have a lip/lock tab like the bearing does on the backing and made to accept a bearing on the inside, and drilled for oil feed. it would have to be a tight tolerance part obviously. I don't see why it's not possible, just it would be expensive... On another note, what about a custom crank instead? May be cheaper and more available..


By the power of gargoyle, may I present Pontiac Street Performance - Bearing Spacers For 3" Journal Crank in 3.25" ? .. it says "nunzi" & "program engineering" sells what you seek.

Neither one of those sells them any more and they aren't the right size anyway.

A new forged crank with the proper journal size is probably $700, plus or minus $100. I'm not seeing the value of reusing the undersized crank by the time you find/buy some custom spacers, get any welding done, final machining, etc. Everyone makes a 3" crank for a 400 block, so that's the easy option, and you'll never have to worry about anything related to the bearing spacers going wrong.

Am I missing something here? Is the forged 317 crank some super-rare, high dollar part?

A new forged crank with the stroke I want and correct journal size is a custom piece and about $4k.

I'm using the 317 crank because it is a 3.25" stroke instead of a 3.75" stroke. I have Pontiac 400 cranks and stroker cranks all over here that I could use, but I want to destroke the engine.