Rod bearing question

So what kind of bearing would you want made for a crankshaft journal that is worn egg-shaped/oval shaped (not round) ??  or even tapered...worn more on one end than the other. Crankshaft bearing tolerances must be held within a couple of thousands of an inch for successful service life.

would never last long enought to get out of the yard ,and not to mention all of that metal ready to grind somthing easle apart

I'll bet "Hayes" could could come up with a solution as they have with fasteners:

Ok, so it may be possible to only need rod bearing if they sell undersized shims if not egg shaped. Or a knock sound could be a broken ring or something else...

Hmmm, ok so it may be worth looking into if I need or can utilize and undersized bearing on my G188D motor. She's a smoker and I bet at a minimum it needs a upper half overhaul kit, would cracking line loose on each cylinder for the injectors tell me if that cylinder is one making noise by stopping it from firing?( I'm trying to figure the theory of doing that one out!Thanks for the info

As mentioned above, many older engines (not just AC) were designed to allow bearing adjustment using shims; about 20 years ago I did an in-frame freshen-up on a neighbor's Model M Farmall using 0.002" undersize rod bearings. It still runs fine.

I freshened up my 1941 John Deere Model A about 30 years ago; it has the poured babbitt rod bearings with shim adjustment. I forget how many shims I removed, but it wasn't over 0.003" or 0.004". I'm pretty sure my grandson will still be running it after I am long gone.

Some years ago an old retired mechanic friend was cleaning out his shop as he was downsizing; he showed me some tapered shims for putting underneath rod bearing shells. He said he hadn't done that in many years though. I wish that I had asked him for them just as memorabilia.

I have seen rods that someone filed the caps by hand to tighten up bearing clearances. The engines ran successfully for many years, but I still do not recommend it.

What is a G188-D engine ??

Codger wrote: I'll bet "Hayes" could could come up with a solution as they have with fasteners: I know this is a funny but I've 'modified' many a bolt to make things work. When you've got a die that needs to go back in the press, you do what you have to do! Turning down the shank so you can get proper cutting clearance not that uncommon. Trimming the head because the die block has been sharpened to death and should have been replaced long ago....

Well then, a diesel engine that you want to try and patch up a rod bearing ?? That is a BAD idea. Deezel engines have twice the compression as any gas engine and have more pound to them when they fire. You've got a knock you say ??   Does the exhaust emit any white puffing smoke ??  A really bad (beyond fixing) rod bearing will lower the compression on ONE cylinder and can make it knock and partially miss-fire. The piston could also be hitting the cylinder head if bad enough. I saw a D-19 turbo-deezel that bad once and it only took a new crankshaft and connecting rod to fix it.

Hunt, i think the moral to the story is that a knock , can be a rod bearing, can be a wrist pin, can be a cracked piston... or who knows... You really cant tell until you do a Complete inspection......... If you doing it in frame, and pulling the head and piston / rods out ... you can leave the crank in the tractor "until" you determine the extent of damage and if the crank journals are round or not..... at this point, you just dont know..

You haven't answered the question about the exhaust puffing any smoke, white or black. Your engine is not a direct injection engine. It is the old LaNova system like Buda and Oliver used. They do not "knock" from cylinder firing. They are smooooth. So, if you have a knock, I'd bet it was mechanical.

Wow, thanks for the story! Gives hope to enginuity😜

Ok sooooo, pulled drain plug today and green anti- freeze( probably about a quart) came out first then oil so I'm guessing I've got a blown head gasket to start with... Probably the cause of my white smoke. One positive about the short time I was able to spend after work before dark was one of my worries was breaking free my lug nuts on all 4 rims, which had me worried a bit since these tires look original and probably never been off but thankfully looks like some never seize was on threads! It will be a long process but it was at the right price and I'm not in any hurry to get projects done I have planned so I'll need some more time to explore and fix her up!

YEP... just like ALLIS... could be liner o-rings , could be freeze plug, could be gasket.