alright, i did some searching but didnt find a lot. Im building a NA lsvtec motor and i was wondering if i should replace the main and rod bearings or not. Its a b18b1 with 145k on it, but the bearings are within spec. So should i change bearings or keep the factory ones with all those miles. I have people telling me to change them and people telling me not to if they are in within spec so i dont know what to do. The bearings have no abnormal wear and the motor was never squized on or anything like that.. the bearings seem to be in pretty good shape. What are some of your guys's thoughts on it?

 

are you serious?....bearings is one of the first things to replace....even if they are within spec they still have 145k.

 

any time you bild a motor the first thing you replace is bearings or it goes BANG

 

it goes bang huh? lol... yea ok i kinda fegured i should get new bearings. To me there is no question about it... but i had people telling me as long as the bearings are within spec their fine. thanks for the help.

 

Rebuilt motor = New bearings

 

Has anyone ever heard of keeping the original bearings on a rebuilt motor?

 

Yes, I have heard of reusing bearings. Have seen it a lot in road racing engines in showroom stock. Doesn't seem to hurt engines reusing bearings if there is no scoring on them. In fact, used bearings can free a bit more HP due to not being extremely tight oil clearances. In fact, if engine was very healthy before rebuild, bearings should be minimally worn or not worn at all. (Remember, parts do not ride on surfaces of the bearings but rather the oil in between them). I have personally reused (main bearings only) on H22 prelude and engine still going very strong with more than 45k on rebuild. This engine had 100k before build. Crank has been knife-edged, new performance rods, pistons, cams, valvetrain, etc., etc. If bearings are inspected to good would have no problem reusing at customers request. Now, I personnaly do not reuse bearings if I have a choice about it, or suggest so. Again, have only reused at customers request.

If not reusing same pistons on same crank, you would need to replace bearings anyway, due to different clearances obtained. But if same crank and same block and no line boring was perfomed, just engine refreshening, could reuse crank main bearings if condition permitted.