SO i will be installing New Bearing on my H22 motor. ITs a JDM motor that a bought about a year ago.. and Well...im rebuilding it, to get it run OEM. SO i used the service manual and figured out which bearings to buy. A friend of mine told me that i should buy a size smaller bearing then the one that was coded off from the block and crank, etc. He says this because it is a used morning(JDM H22) and because i plan on micropolishing the crank. HE says this rule of thumb worked for him when he built his b16. I know that most of you would say just measure it, but i dont have measuring instruments for this. I hope i explained my situation good. any help is appreciated.

 

Well, I would say rent the equipment needed. Or have a machine shop gauge it. you never want to just take advice and go with it with any doubt. You'l end up getting the short end of the stick. Trust me! I would get that crank checked, and if all is well, buy an oem bearing set for the rods.

 

i definetly plan to buy OEM bearings for mains and rods. Well.. ive gotta figure out where to get these tools. Basically all i need is A micrometer and telescoping guages right?

 

Go to AutoZone and spend $5 on a package of green sized Plastigage. Then you can check your bearing clearances instead of guessing.

 

smaller bearing = more oil
larger bearing = less oil, longer lasting

At least that's what I've read. I'm no block expert, correct me if I'm wrong.

 

From what I've been learning, about .0015" on the mains and .0017" on the rods is pretty good. The extra clearance on the rods acts as a bit of a combustion cushion.

 

when you say 15 and 17 thousanths....do you mean thats good for oil clearance?? Also...i plan on measuring the journals of the crank and bores of the rods. If i can remember i measure the journals then measure the bores and then Do a lil math right? Bores minus(-) journal right? then that will give me how much space the bearing must take up, minusing the oil clearance. Some one shoot me in the right direction a bit. I lknow your thinking ...take it to a shop....but i honestly can do this...just need a lil guidance. The manual doesnt tell me much about which bearings to buy when your doing it to a used motor. It says follow the code on the crank then by corasponding bearings to that, then plastgauge. Then if that bearing doesnt work get new ones. But i dont think bearings are returnable. so i want to avoild all that if i can. Let me know guys thanks!!

 

I bought a set of green bearings to Plastigage with, then ordered what I needed.

Yeah, those are supposed to be good for oil clearances...per professional builders on this site. I have all of mine at .0015".

Rod bore ID - Journal OD + desired clearance = bearing thickness needed. There's a bearing thickness chart in the All-Motor section.