Fully Grooved Main Bearings

Do you think having the bottom (cap side) main bearing fully grooved is good or bad?

At first thought I figured it was bad because of less bearing area. But the more I think about it the more I like it. It seems like it should more evenly get oil to all areas of the journal. Also, it should more consistently feed the rod bearings.

I'm sure cross drilled cranks will come up in this conversation. Is yours cross drilled?

 

If you look at the way a hemi crank is drilled, you will see that the rod gets its oil when the oil hole in the crank feeding that rod is lined up with the groove during TDC. Thats when you need the most oil. I have been told that fully grooved mains are not good, too much bearing area is lost. I have also been told cross drilled cranks are weaker where they are cross drilled. Tom.

 

groove

BAD idea don

 

Bearings

I tried grooved bottom bearings one pass and it is not the thing to do if trying to run hard. I believe you will regret it as I did. Just my two cents worth. Rich