Cummins rod casting # confusion

Further investigation tearing into my blown indouchtrial motor reviels 5 - 24v rods with a casting # of 3942578 and a 6th rod with a casting number of 3942579. Rod ending in 79 is .020 shorter than the other 5. WTF is up with that? Who builds a motor and uses two different rods? Being the casting numbers are close I understand that mistakes happen but what im wondering is: What is the origin of each rod and why is the 6th rod odd ball and .020 shorter? Visually they are identical. Any help in tracking down the origin of these two different rods that are otherwise visually identical would be very helpfull. :thankyou2:

So center of the wrist pin to center of the rod bearing is .020 shorter or over all length is shorter. If it is overall length that isn't anything to worry about

I bought a set of "factory shot peened 12v marine" rods from one of the biggest names in 5.9 performance, when I got them out of 6 rods they were made in 4 different countries. USA, England, Brazil and either China or Japan.

Don't remember details on numbers.

They went back.

DISTURBED said:

So center of the wrist pin to center of the rod bearing is .020 shorter or over all length is shorter. If it is overall length that isn't anything to worry about

Click to expand...

Center - Center is off.

Big end must have been sized and it slipped by. (No excuse for it...but the reason for the difference).

Thats why im trying to find out if there is a difference between the two casting numbers thus the .020 shorter rod or is it an altered rod. Inaccurate sizing of the journals or simply a different rod all together.

Thanks for your replys.

Just a little more info. The 5 longer rods were cast in England. The shorter is a Brazillian cast.

The Brazil rod was rebuilt on the big end .That involves grinding the .02 off the cap and rod mating surface and then torque bolts and hone round to bore spec. got good bolts ?