While I'm in there...an internal engine question for the hive

I'm looking for opinions from you all on rod and main bearing replacement with the engine in the car.  I replaced the oil pan on my 1969 351C Cougar as the cheapy chrome pan seemed to ooze oil directly through the steel.  As I was cleaning up the block to start the install of my new flywheel I determined that the rear main seal was leaking and had to back track to drop the pan again.  When I pulled the rear cap with the seal I saw the bearing was worn and had a copper sheen in the lower center about 1/4" wide (towards front of car though tapering at both ends) and about 1" along bearing radius.  The motor was rebuilt by a local garage during the PO's time and now has about 3k on it.  From my title, you may have surmised my question (insert Captain Obvious image here).  Should I/would you pull all the caps and replace the main bearings?  How about the rod bearings?  Both?  What type of job is this with the motor in the car though on a lift?  Car is a mild-engined cruiser that sees summer duty only though I am thinking about a MI to FL road trip for this years Challenge in it.  

In reply to wawazat :

I've done both of those things with the engine in and with it out. It's easier to get everything to seal properly with the engine upside down if you can get your hands on a lift and stand, but you can manage it in the car, too, it just takes extra time and care. I didn't have a lift, just jackstands.

One of two ways forward. Fix it or pray.

You've got copper showing. probably best to rebuild the whole engine. Way easier to just pull it. This is the way I always choose, and why I'm poor.

Or, wiggle/pull the rest of the bearings, and see. Replace as needed. I know plenty of people who only replace what absolutely needs it. Perfectly logical way forward, but you have to accept you may have to do it many times. Catastrophic engine failure can happen if you push it.

3K on rebuild and wasted mains. I don't like those odds.

If it's showing that much wear with only 3k miles on it I'd say it wasn't rebuilt correctly to begin with.  I vote pull the engine and do it right, it will be worth it.

"If you can't afford to do it right once, how can you afford to do it twice?"

Patientzero said:

If it's showing that much wear with only 3k miles on it I'd say it wasn't rebuilt correctly to begin with.  I vote pull the engine and do it right, it will be worth it.

 

"If you can't afford to do it right once, how can you afford to do it twice?"

That's what I'm thinking too. There is something seriously wrong with that engine. Main bearing saddles out of alignment/improperly line-bored, a bent crankshaft, insufficient bearing clearance, oiling problems (particular sore spot on Cleveland engines). 

I would pull all the bearings and see what they look like and make up my mind from there, however I would be leaning towards pulling and rebuilding.

Lot of factors go into that, though.

I'm headed down the all new lower end bearings and seal her back up while looking at new motor or rebuild this winter.   Convertible season is in full swing and want to drive this thing again soon!

My strong suspicion is that PO did a low-bid clean and rebuild without much machine work.  Perfectly fine for his intended ice cream shop runs with the grand kids.  I have different goals however.   I was just thinking I've dove in to every system on this car excluding the engine.  That just changed

351 Cleveland, right?

Those are getting thinner on the ground. It would be a shame to ventilate yours.

While you are in there, you might as well check a couple of the rod caps as well and see if it extends to them.  Might be worth installing a higher volume pump and/or thicker oil as a preventative measure.

About 12 years ago I replaced the rear main in an old sbc. With the rear main cap off I saw a fair amount of copper, about what you describe. I told the owner of the truck and recommended a rebuild. They never did. They still drive the truck with the questionable bearings. What I'm trying to say is sometimes you can get away with it, those old iron lumps were built pretty tough and dirty.
 

I would check a rod bearing or two, if those look bad you may want to do something about it. I think that failure mode happens faster and more dramatically. 

If there were no symptoms (bottom end noise, low oil pressure), I'd make like the scorpions and rock it like a hurricane.

351 Cleveland, correct.   They are thinner on the ground but are still available.  I do want to keep all the insides inside and not create a windowed block but this thing sees pretty light duty.  The oil pump was brand new at previous rebuild.  I'm going to move ahead with all the lower end bearings-main and rods-then drive.  With the 5 speed and 3.70 Auburn rear end it may see some long overdue burnouts when I get those wheels and tires from Patrick.

Yeah no noises from the internals.  Bearings are for my peace of mind as I decide what the next motor looks like.  Not gonna lie, I've got a pretty good idea already formulated.