rich7777

Hey guys

I took my sump off at the weekend to inspect the bearings in my b18 to see if they were scratched as i had a issue with a faulty turbo that had scratches on the outside of the turbo bearings. I'm not to sure what caused the scratches yet but i'm thinking its most likly carbon as the oil seal was gone in the turbo and had a lot of carbon build up inside the turbo.

I found that there was a few scratches smack bang in the centre of some of the main bearings. The rods were fine with no scratches what so ever.

Now my question is can anyone give me a reason why i could'nt just change the bottom main bearings and leave the top ones ? The engine has seen no abuse what so ever and has covered around 3000 miles. I can clearly tell by looking at the bottom bearings that there will be no scratches on the top ones.

Thanks guys

farfrumugen

you should ALWAYS change bearings in pairs. without looking at them their is no way you can say they are good. also what does your crank look like? if their is any scratches at all you need to have it polished or it will score the new bearings. you should just pull the crank since your already their and do it right. no need to half *** it.
adam jeffery

rich7777

The crank is fine, i cleaned it up with break cleaner and took a close look at it. I can tell by the look of the bottom bearings that the top are ok. The top bearings have that dip in the middle and the scratches
are only in the middle of the bottom bearings.

I know what your saying about a half *** job, but this engine hasnt done 60,000 and seen a load of abuse but or nothink.

What is the reason for changing bearings in pairs ?

Thank you

tales sol

you change the bearings in pairs because they wear together.

fitting a half a ste of new bearings could really mess with your clearances!

rich7777

Yeh true but they havent really done enouth mile to see any wear. Engine bearings are ment to last a long long time.

farfrumugen

sounds like you made up your mind! why even ask for the proper advice....ill be watching for your post about crank failure in 10k miles.....lol
do what you want or stop being lazy and change them correctly

rich7777

So you say..... I still havent got the answer i was looking for. There is no way on this earth either bearings would of worn enouth to cause a problem with the clearences if i replaced just 1 half. If they had then we would all be rebuilding our engines after 30,000 miles or so....

I emailed Laskey racing yesterday and Mike told me it would be fine just to change one half.

farfrumugen

if their is scratches on 1 half their will be scratches on the other half. scratched bearings wont hold the oil as well against the crank and will deteriorate at a faster rate.thus wearing your crank and making clearances even worse. if someone told you otherwise they are an idiot.
NO you cannot change just one half. youre in the engine already, your a few bolts away from changing the other half. why would you not just change them, you buy them in pairs so you have them already and your minutes away from changing them. why is it so hard to just change them? i dont see your logic.
please explain to us WHY YOU ONLY WANT TO CHANGE HALF? youd have the job done already if you were not on here trying to get the answer YOU WANT to hear. instead you take solid advice and disregard it as if we have no idea. well let me tell you i have built many engines, not all hondas and i have never once thought...hmmm ill just change half, the top must be good since i cant see it. and send it out. YOU JUST DONT WANT TO DO THE WORK TO GET THE JOB DONE PROPERLY. take our advice and just change them. or dont ask in the future.

rich7777

1. The scratches are in the middle of the bearing. The top bearings have a dip threw the middle for the oil supply so by looking at the bottom bearings theres no way the top will be scratched.

2. I have to take the gearbox off and on, on my own in my garage which is a nightmare for me.

3. Apart from the scratches on the bearings they look fine. There is no sign of any abnormal wear.

4. They have covered next to nothink milage wise

5. They cost over £20 per bearing over here.

6. Mike Laskey knows his stuff, check out his site laskleyracing.com