main bearings, fully grooved or flat?
 

Okay i was looking at another crank that i had for my A20 and ive seen on my old a20 and the donor engine (both stock engines) that the center main bearing (number 3) has a 2 grooves wore in it from the bearings (the center of the journal has a ridge). Im wondering if i should just get flat bearings instead of the stock fully grooved shells or is this gonna eff up my rod bearing oil supply? This engine is gonna be a high hp build and i want it to hold up.

Re: main bearings, fully grooved or flat?
 

You mean the crank journal has a ridge worn in it? Sounds like a crank problem.

Those oil channels are there for a reason.

Re: main bearings, fully grooved or flat?
 

fully grooved bearings, even if the crank is cross drilled.

Re: main bearings, fully grooved or flat?
 

High HP a20 Cant wait to see pics/vids :y

Re: main bearings, fully grooved or flat?
 

IIRC the #3 main should have only one oil inlet hole coming from the block and doesn't feed to any of the other mains or rods. It should have a grooved bearing surface on the block side and a flat bearing on the main cap side for all of them, and #3 is usually a looser tolerance than the other 4 mains. Might want to take a close look at your crank before you reuse it, although it may be just fine because most lead type bi-metal bearings are made to "imbed" any possible particles that might groove your crank.