Small block crank

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Sterling

Sterling

FABO Gold Member
FABO Gold Member
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Anyone running a crank turned .040 under on the rod journals? I picked up a 1967 340 short block that was built to race, started and ran a little but never raced. It had a set of W-2 heads on it that leaked. So I got the short block cheap. I was comparing the steel crank to another one I have here and found out the rod journals are turned .040 under. I have heard of cranks turned down to 2.00 , but not with stock rods.
 
What was the old saying....Thicker the bearing ...the less heat in the oil/or cooler running journal.... I cant remember now.but think along those lines.
I guess I'd just run a babbitt/harder bearing if I were worried about the bearing thickness...assuming that's the concern to begin with. Jmo
 
I had a stock 360 crank cut down .030 last year but I had them wait till I had bearings. I found a set of fully grooved bearings on eBay so they cut away so I would check availability before doing anything
 
This engine was together and running before I got it. The bearings look brand new, and I am going to check the clearances. If the clearances are good, I was going to reuse them
20220114_121834.jpg
 
Sterling said:
This engine was together and running before I got it. The bearings look brand new, and I am going to check the clearances. If the clearances are good, I was going to reuse themView attachment 1715852790
Click to expand...
I use new bearings each time. They go through a torque cycle a time or two and loose their crush. (from what I have heard.)
 
I always do too, except for this engine, that I don't want to stick any money into it. If I don't like the clearance, I will put another crank in it, with new bearings
20220114_122235.jpg
 
I will check the stroke, but looking at the piston and rods, I don't think it is offset ground
 
undersize bearings have same thickness of bearing material, the steel backing is where the added thickness is made. smaller dia , has less bearing speed and friction. makes more power.
 
Sterling said:
Anyone running a crank turned .040 under on the rod journals? I picked up a 1967 340 short block that was built to race, started and ran a little but never raced. It had a set of W-2 heads on it that leaked. So I got the short block cheap. I was comparing the steel crank to another one I have here and found out the rod journals are turned .040 under. I have heard of cranks turned down to 2.00 , but not with stock rods.
Click to expand...
Personally, I think your safe. If this works at .200 off set and .300 off set, .040 is good to go.
Crank Shops for Offset Crank Grinding? | For A Bodies Only Mopar Forum
 
I didn’ Know you could get 0.040 under S/B bearings?

The smaller the bearing surface the less friction you have.
Mopar journals are pretty big compared to modern engines.

Big blocks run the Chevy rods now with 2.200 rod journals.
Not sure what is available in the S/B world?
 
Big block Chevy Pro Stock engines have been using Honda rod journal sizes for close to 20 years now. Their Ford and Dodge counterparts have as well. It's real common for most small blocks(Chevy, Dodge and Ford)to use Honda journals these days also.
 
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