Crank rod bearing update with pictures

I recently made a post about putting new crank bearings in, Ive got some pictures now.

I have a Massey Ferguson 165 Perkins diesel, the engine is out and upside down on a stand, Id like to just replace the rod bearings without removing the crank, the main bearings are in spec and look good, the rod bearings are out of spec and one is scored, the crank journal has a small ridge I can barely feel about 1/2 around it. Just wondering if I could get by with just new rod bearings, maybe polish the one journal? Pics are added.

Main bearing clearance: .003
Rod bearing clearance: .002

No way would I put that back together without turning that crank. I did one that looked much better than that and was within spec and still turned a rod bearing. If the crank looked smooth andre bearing was worn but smooth, I would stick new rod bearings in and go. That crank looks to me to need turning. Your talking about $300 +/- and I think you will regret not spending it.

Easy for me to say as I aint footin the bill, but I wouldn't even consider just sticking another set of rod bearings in there. If I am looking at pics right crank needs ground. Plus feeling a ridge 1/2 way around to me is worse than all the way around? You have no idea what the piston pin bushings look like on the other end of that rod. I would be putting new pin bushings in and getting rods checked and resized, check pins while you are at it. I can see why you are hesitant because once you start it will probably turn into a major over haul? Maybe an illusion in your picture but shank of rod bolt looks smaller than the threaded section? Caps do not look like they have anything to locate them on the rod so the bolt shank should be a reasonably tight fit in the bolt holes of cap, I think? I dont have much experience with the Perkins in your 165 so I am sure others will correct me. Another thought is were there match marks on cap and rod? maybe was out 180? It would probably be a good idea to get someone in the know to have a look at it in person. Maybe someone from your local automotive machine shop?

Diesels are very unforgiving.

I give it another no vote.

ooh my, not good. that crank needs work. those brgs are bad.

You cannot eyeball that mess and make a sensible decision. Try cleaning it up first to see what you really have. All it will cost is a piece of sandpaper and an hour of your time. Take a piece of wet/dry sand paper, 600 grit. Cut a strip to fit perfectly around the crank pin, and tape the ends together. Put 1 wrap of rope, small hose, or a spark plug wire around the sandpaper and pull the end alternately to make the sandpaper rotate. After about 15 seconds you will have a surface you can accurately measure. You have to have a light touch on the rope; do pull both ends too hard or it will choke the sandpaper against the crank pin and it wont turn. It will turn hard for the first few strokes as the high spots are being cut off and/or the sandpaper wears out slightly. Before taping the ends together, though, put a dot of oil on the crank pin to keep the sandpaper from plugging. After you get it turning good, you can simply spray some penetrating oil on the edges of the sandpaper to keep the cuttings floated out. The method of measuring is whatever you like best. If you come up with .0025 clearance with a new bearing insert, Id say you are in good shape. Any more than that, I would call some suppliers and see if anyone offers bearings in undersized of .002-.005 inches. Failing that, Im afraid the crank will have to come out.

Pay now or pay later. Your choice but the first time will be less work since it is already on the rack and parts will be more later as you will have already spent money once and then same again. Turn it and a set of bearings. If you want to cheap by reuse a pan gasket or something like that. Reuse the old clutch. Not doing the crank work would be merely foolish to me. I hate spending money on parts if I can avoid it.

From the looks of that bearing I find it hard to believe that crank doesn't need regrinding.
After cleaning the journal up have someone who is experienced in measuring crank journals check it for out of round. You might find that it is out of round and just using plastigage isn't the most accurate way to check a crankshaft. As was mentioned before it's your money and you make the final decision. My thoughts are based on 25 years of working in an automotive machine shop.

Pull the crank out send it off and have it gone over its not that hard to do it right and will cost less in the end

As said pull it out and do it right you'll be way ahead in the long run.

Send it out, and let the shop get the bearings.

I've overhauled many engines and by the looks of that crank, it needs to be sent to a machine shop along with the rods.

Unpopular view but onelonleyfarmer on youtube had a spun bearing on one of his older tractors a few years back, a 4320 Deere IIRC. He didn't even pull the engine, just polished it up with emery cloth and put a new bearing in. Fired it up and deemed it just fine, not going to fail, all the commenters saying he needed to have the crank turned didn't know what they were talking about and should just shut up.

Of course we've never seen that tractor run, move, or do any work on his channel. Just sits in the back corner of his shop.

Frankly if you're willing to pull the engine down again if/when the bearing fails, then polish it up and put a new bearing in. You've got nothing to lose really but your time and the cost of a bearing.

Fourteen years ago I had the oil pan off my Ford 9000 with 10,000 hours looking for a bearing problem. I couldn't find any in the mains but the Rod bearings were showing a little copper here and there. The crank journals all looked smooth as chrome. We decided that the sound that I was hearing was piston slap. So I replaced all of the bearings, rolling the new ones onto the crank. Since then I increased the RPMs and the fuel bringing her up to around 500 HP, and regularly for five years used every last one of those ponies. She seemed to run stronger all the time.

Huge difference between running 500HP for 300' once a week, and running 500HP for 10 hours a day, 6 days a week, in the field.

Listen to Rusted, crank issues you can feel are not good. You have done 90% of the work. You will need a book to set the timing gears and on a 203 Perkins the marks once lined up may appear incorrect if you rotate the motor after initial alignment.