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302 rod journal size?

17K views 7 replies 5 participants last post by  turbostang 
#1 ·
Is stock 2.100 or 2.123?
I am tired of searching. I am coming up with both.
 
#2 ·
stock Ford 302 rod journal is 2.123"
chevy rod journal is 2.100"

Most 2.123" journal rod have .912" pin dia
Most 2.100" have .927" pin dia

2.100" wont work on a stock 302 crank.
 
#3 ·
Thanks! I've been looking at stoker cranks all night and have seen too many options. Any benefit from a 2.100 rod journal?
 
#5 ·
Clifton said:
Thanks! I've been looking at stoker cranks all night and have seen too many options. Any benefit from a 2.100 rod journal?
I don't see any but if this question was answer by a Chevy person then he probably said smaller dia will give longer bearing life.

Eagle kinda screw this thing up pretty good...most of their forged crankshaft come with 2.100" rod journal.

This also confused lot of people...not too many heard Chevy rod journal on a Ford crankshaft...
 
#6 ·
I've heard that the smaller diameter means less bearing surface area which means less friction which means longer engine life/easier revving, but I'm not sure if this is true or to what degree.

I do, however, know that stock small-journal Chevy rods came with 5/16" rod bolts and aftermarket rods are a little more scarce and/or expensive.
 
#7 ·
tphan said:
I don't see any but if this question was answer by a Chevy person then he probably said smaller dia will give longer bearing life.

Eagle kinda screw this thing up pretty good...most of their forged crankshaft come with 2.100" rod journal.

This also confused lot of people...not too many heard Chevy rod journal on a Ford crankshaft...
Nearly all Ford big block stroker kits (385 series engines) use big block Chevy rods with a 2.2" rod journal.

Stevo
 
#8 ·
That_Is_My_El_Camino said:
I've heard that the smaller diameter means less bearing surface area which means less friction which means longer engine life/easier revving, but I'm not sure if this is true or to what degree.

I do, however, know that stock small-journal Chevy rods came with 5/16" rod bolts and aftermarket rods are a little more scarce and/or expensive.
This is true, a bigger diameter bearing has to travel a longer distance (circumference) from start to finish compared to a smaller bearing. (the circumference of the bearing is bigger on a bigger rod journal)

circumference = Pi * diameter

2.100 * 3.14 = 6.594 circumference
2.00 * 3.14 = 6.280 circumference

I've read a ton into this stuff, but I don't ever recall seeing back to back tests..
 
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