Crank Journals worn too small?

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standup303

standup303

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I have a steel crank I want to use, went to measure the journals to order bearings and they are smaller than the journals on the cast crank I have and the stock specs. Still have not had it grinded/polished yet either.
Going to drop it off at the machine shop in a week but want to get the bearings here so I have everything. Is there a bearing that fits these?

My Steel Main: 2.719
My Cast Main: 2.748
Factory Spec shows supposed to be 2.750

My Steel Rod: 2.344
My Cast Rod: 2.375
Factory Spec shows supposed to be 2.375
 
Maybe you could tell us what engine we're workin on? I'd GUESS the steel crank is .030 under.
 
Yeah, you've got a .030/.030 crank.
But WHY do you want to order bearings BEFORE you know if the machine shop will have to take another cut off of it?? Or even pronounce the steel crank to be too far gone? Then you're sitting there with bearings you can't use.
 
As previously posted get it inspected/polished first... .030 under is not a big deal... Lotta guys these days have journals turned much smaller then that... IE Chevy size 2.200 rods...
 
I agree A .030 .030 crank will run fine, but why do you want to swap it? A Chrysler nodular cast iron crank will take 500-550 HP. Be honest with yourself. Are you really going to make that much?
 
Even if it's used up past 440 dimensions, it can be ground for a low deck and BBC rods and serve a long time further. S/F....Ken M
 
RustyRatRod said:
I agree A .030 .030 crank will run fine, but why do you want to swap it? A Chrysler nodular cast iron crank will take 500-550 HP. Be honest with yourself. Are you really going to make that much?
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He might not wanna change the balancer, vert plate etc. Nothing wrong with external balance, just simpler going internal 'parts wise' especially if he already bought them. Jmo
 
MOPAROFFICIAL said:
He might not wanna change the balancer, vert plate etc. Nothing wrong with external balance, just simpler going internal 'parts wise' especially if he already bought them. Jmo
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I was assuming he already had a complete cast crank engine.
 
I have both complete cast and a forged motors. Guess I’ll bring both cranks, flex plates and balancers. I did not realize that polishing could take that much off. I saw summit carries mains that are .010 over and thought I could just order some .030 over. Still learning. I’ll let the machine shop do their thing.
 
standup303 said:
I have both complete cast and a forged motors. Guess I’ll bring both cranks, flex plates and balancers. I did not realize that polishing could take that much off. I saw summit carries mains that are .010 over and thought I could just order some .030 over. Still learning. I’ll let the machine shop do their thing.
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If that much was polished off the journal is neither straight nor round.
 
You can also get the crank hard chromed to build up the surface, which is then re-ground to size. Expensive here, not sure in the US. Depends on how valuable the factory steel crank is to the OP.
 
I’d use the cast crank, use a lighter piston like a hyper rite tic, and internally balance it. The balance job will be more because you need to put heavy metal (Mallory) into in. But the cast is plenty strong and then you can run the neutral balancers, flex plates, and converters. I’ve got a ‘78 440 I’m selling now. It looks almost exactly like a ‘69 including the nuetral balancer but runs a cast crank due to me having one sitting around and the application not needing a forged crank based on power output.

93B859FE-D9FE-43AA-9841-147F1E206535.jpeg
 
Just an update. Machine shop said the journals were pretty much shot. Rolling with the cast crank needs to be ground and polished .010 under.
 
Did they talk about turning it into a B-spec crank? Mains to 2.625 and rods to 2.200. If you're just going to use it for a doorstop, and it's a factory 3.75 forged crank, I'd be willing to buy it and see if I can repurpose it to a low deck. S/F....Ken M
 
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