Quick opinion please - oil pan and bottom of block condition

[abscate]

Replacing main bearings is a pretty big operation.

You have to use Plastigauge and measure the clearance of the bearing by crushing pieces of plastic inthe space, thensourcing the right size bearing to fit the measured space.

There is artistry in the measuring and gauging of a new set of bearings.

[June]

Replacing main bearings is a pretty big operation.

You have to use Plastigauge and measure the clearance of the bearing by crushing pieces of plastic inthe space, thensourcing the right size bearing to fit the measured space.

There is artistry in the measuring and gauging of a new set of bearings.

Shouldn't the crankshaft be turned or replaced before fitting new bearings? June

[JimBee]

ZionXIX: if your engine has been reasonably well maintained you might be surprised how new your bearing inserts look. I was when I rebuilt my 96 855 turbo (it had a bent rod). I took the inserts in their bearing caps, just as they were when I removed the caps, to two different engine rebuilders for their opinion on the condition of the inserts and both said they looked like new—just reuse them, which I did.

There are different grades of bearings—if you were setting up for the race track, you'd want to install the top grade—for both rods and mains. But if your engine is fairly clean without a lot of sludge buildup and your inserts look good AND the crank journals are mirror smooth, just replace your oil pickup o-rings and following tutorials on this site for cleaning things up, put it back together. One surprise I found was the sealant or thread lock on the pan bolts can clog the fine threads in the block. I bought the right size tap and cleaned up all those threads before applying sealant and reinstalling the pan. Menards sells the tap. If you don't do that, you can possibly strip the block threads and not properly torque each bolt.

On the other hand if there is uneven wear of a bearing insert and anything other than perfectly smooth crank journals I'd be thinking about sourcing another engine. It's a big job on the bench to split the block to get the crank out to have it machined, plus all the added expenses of the machining and new bearings. And the main bearings are color coded for precision sizing to unbelievable tiny tolerances. That's done for every engine. You could be dealing with several minutely different main bearings. And if there's wear, like abscate says you'd need to plasti-gauge them which means disassembling, measuring, placing the plasti gauge, reassembling and torquing then taking it apart again to read the smushness of the plasti-gauge, etc for each bearing.

A final thought: if you pull your rod bearing caps and find some uneven wear of an insert, but the crank journal ls perfectly smooth, it could be a faulty insert. You could get a replacement new insert, apply some plasti-gauge on that one journal, reinstall and torque the cap, unbolt it and determine by the plasti-gauge if the fit is proper. If it is, reassemble with a little grease on the insert, and it should be good.

[erikv11]

In this instance I'd clean the oil pan well and put it back on, clean passages as mentioned, nothing more.

Inspect away for edification but not loosen anything or mess with the bearings. Super clean history, still low miles (212k), there is no reason to suspect the bottom end of this white block is in trouble.

[FLXC90]

In this instance I'd clean the oil pan well and put it back on, clean passages as mentioned, nothing more.

Inspect away for edification but not loosen anything or mess with the bearings. Super clean history, still low miles (212k), there is no reason to suspect the bottom end of this white block is in trouble.

+1, unless you had a noisy engine, or reason to believe the bottom-end was worn, Or you just WANT to rebuild your motor, you're asking for it by cracking the rod caps. Everything is happily situated, and even if you "just" check the clearances, you will have disturbed that set. Not guaranteeing doom, but if it ain't broke... Your motor looks great, just clean the pan and the pickup, and put some Robert Spinner miles on that thing!!