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k-star 07-22-2004 11:20 AM

Main Bearings
Ok it's opinion time...

On a non-cross drilled crank. What main bearings do you run, or have you run with good results

1/2 groove
3/4 groove
full groove

Application is a big block mopar, with factory steel crank.


johnsongrass1 07-22-2004 12:48 PM

How many RPM? Power? Intended use? How bout reliabilty? Is it a concern?

Normall I run the full groove bearings to reduce friction loss. But they don't seems to last as long.

k-star 07-22-2004 12:57 PM

6800/7000 ish, should be in the 625 to 650 hp range. drag with some limited street time. It will probably get freshined every year.


Cstraub 07-22-2004 02:16 PM

3/4". That comes from a couple of customers that fool with the Chryslers and hold a few NHRA records.


machine shop tom 07-22-2004 02:38 PM

The Federal Mogul 3/4 groove mains seem to work quite well; they negate the need (if any) to cross-drill the crank.


johnsongrass1, fully groove mains have a severely compromised bearing film from the groove in the bottom half. That's why they don't last as long and why I don't use them unless they are the only thing available for a given engine.

k-star 07-22-2004 04:41 PM

Thanks Tom and Chris,
I was leaning to the 3/4 groove but i read in a chrysler builders book that they suggest full groove. I am with tom i don't like the fact that i am going to loose aproximently 1/4 of my load bearing surface with a full groove bearing. But i do understand the importance of feeding those large rod journals with plenty of oil. So i was thinking the 3/4 would be a "best of both worlds" situtation..


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