Well I spun a bearing a couple weeks ago, making a pretty bad knock but I think it still might be salvageable.
Today I'm going to pull the oil pan and see if I can get away with just putting new bearings in.

Only thing, how can I tell if the bearings that are in there now are stock or over sized? The PO had the motor rebuilt at a Mitsubishi dealer, probably about 10 years ago. Would they have used over sized bearings?

Thanks

It's usually stamped into the bearing. Most likely, unless there was a catastrophic failure, standard bearings would have been used.

I was about to post a similar question. With 160k on my 1989 V6 should i replace the bearings before I have an issue. How difficult is this job.

Unless you're having an issue, no. Don't fix what ain't broke. If you're curious about the internal condition, have your oil analyzed at Blackstone.

You'll get about 1000 miles out of the new bearings before they knock again.

I'm a big fan of replacing the rod bearings and oil pump as preventative maintenance on the 6G72.

IMHO, if there are any problems with the crank, replacing the bearings will be a temporary fix at best. These engines are incredibly durable. They are also quite intolerant to any problems on the bottom end. They just don't respond well to being patched together. There is a reason the "re-manufactured" engines have a poor reputation.

I'm not saying you don't have the skills to pull this off, or may get lucky. For myself, I would feel better spending the cash at the local Indian casino. <img src="/forums/images/graemlins/lol.gif" alt="" />

<img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/rodent.gif" alt="" />

yep align bore and resize along with a crank turn/polish there is never time/munny to do it right the first time....... but funny how you can find time and munny to do it over <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

Thanks, yea I know to check the crank. I have other projects going on now and really don't have the time, money or interest to rebuild or buy a new engine for this rig.
A buddy has a lift in his shop so I'll try to bring it over there and take a look.

How can I tell if the crank is OK? How much scoring is too much?

if there is any scoring its to much. you also have to measure the shaft lobes to make sure they arent worn down to much and are still actually round. there are a ton of measurements you can find in the factory manual. and dont use cheap stuff to measure with. the tolerances are small, you need good tools.

Rake a penny across the journal. If it leaves a mark, the crank has to be turned/polished.