955L cat loader motor issues (grey market at that serial)

we have a 955L we just purchased an it has had an awful knocking in the motor,,, pulled it out an was guessing for bad crank an a rod or two ,,, needless to say pulled the head off an the number 4 piston has been busted an the top all beat up due to it dropped both valves into it,, pulled the bottom apart to find the cranks in perfect shape an all rods are fine,,,, needless to say the motor serial number tag on block matches the same serial number to the tractor 31J773 called cat an talk to my friend an he looked it up an the tractor is grey market an from Japan. so I went to my after market parts guys that I get all my motor kits from an gave em the part numbers off the main ,rod bearings an piston numbers an cant any one get the parts,,,there good numbers but the availability is from Japan,,, so I called my cat dealor back an gave em the piston number an he looked it up an said he had a piston sitting in a warehouse up north but couldn't do anything with bearing numbers,,, me an my cat guy have allways dug threw cat sis till we found an American serial number tractor close enuff to use to go by to order our parts buy, but were having issues with this motor unlike we have before... this motor I noticed when I removed the bottom end I found that the main an rod bolts all had cotter pins threw em to hold the nuts from backing off,,, never seen that before.. also the motor is old enuff for it to have a canister oil filter an not a spin on. not sure what were gonna do ,,, not sure if we find a lil newer motor if we can adapt all our exhaust an intake manifolds too,,, I know on a few 955L s ive worked on before they had the big square injector pumps an differ style belt tensioner,an they have the big heavy intake manifolds. any idea guys what to do ,,, just scared if we went with an whole completely newer motor with out changing an putting my older stuff on newer block that my hood would fit properly or would have to modify with cutting hood up... don't wanta look shady.

seeings the piston went into the head and dropped valves if it was me i,d pull it completely down, send the crank,rods (mark the rod where there was a problem ) check them for straightness, rebush them all, replace rod bolts in rod where problem was, check crank for straightness-polish or turn as necessary, magniflux block especially where the problem cylinder was, check align bore, bore-hone cyly as needed, check deck and surface if needed. check head for damages and cracks,do valve job and surface as needed, replace the injector in bad cylinder. too much as risk to cut any cornners imo. hope it turns out good for you.

Thanks for ur reply but the problems with my motor is that with it being a grey market serial number I cant seem to get any parts for it,,,parts found are in Japan an that's a bummer not knowing if an when an the cost to getem here

What are some of the part numbers that you have?

Starting to wonder if it is a K model and maybe the S/N prefix is 71J (1968 to 1978) which would put it in the Japan market. Is the what your oil filter looks like

More info, now I'm thinking it may be S/N prefix 60A due to the bearing caps. Which puts it in the 1960 to 1967 range and a 955H model
7M4303 CYLINDER BLOCK ASSEMBLY
SERIAL NO. 60A8413 TO 60A13706, 60A13708 TO 60A13711, 60A13713, 60A13715, 60A13717, 60A13725,
60A13729, 60A13731, 60A13733 AND 60A13735-UP. PART OF CYLINDER BLOCK AND COVERS SHOWN ON PAGES 26 & 27A

If it is a 31J machine as per the OP's information then the equivalent for parts in the US would be a 61H-prefix US-built machine. That prefix exists in the Cat SIS system and any dealer or parts supplier should be able to supply parts to fit the 31J based on using the 61H.

BTW the 31J prefix is not a 955L, it's a 955K, whatever decals might actually be on the machine.

My thought of the H model is the mention that the bearing caps had cotter pins. I kept backing up until I found the one above

Hello friend,,, I talked to my cat guys again today an he played around with the early serial numbers around the 71j area an looked up the piston part number an it don't match the piston number outta my grey market,,,, he was gonna keep digging round with early numbers an get back with me,,,, I looked at an motor outta a guys 955l from up the road an blocks totally differ. plus the head is smaller an don't stand as tall as mine on grey market motor. also mine has the cartreidge type (inner) filter as a oil filter instead of a regular spin on element. my cat guy even went threw some of his ole micro fishs an threw legacy parts. some of my parts do have regular cat part numbers on them too,,, my block is a part number 4S5400x an it has the long injector pump on it instead or the regular small square box type. an the serial on my block an tractor both are stamped with same 31J773 number.

and the cranks number is a 8M8500x I think my cat guy tried to find the crank an piston number it other early serial numbers an never found anything,,, I use to work for cat for 8 yrs an I know how we use to could email the head cat guys up at the head place when out head tech service guys got stumped on stuff an they answer our email to help us,, I asked my cat guy if that was an option or was our issue dealing with grey market not important an too old to bother them head guys with. ill get with my cat guy in morning to see if he came up with anything today

Hey friend,, its possible the machine was installed with wrong decals,,, but I had gave my cat guy at cat several differ part numbers off my gray market motor an he looked threw sis an legacy parts an the old school micro fish cards,,, he never could find my grey part numbers in any other regular cat serial numbers breakdowns,,, I gave em my engine block part number today hopeing he came up with something with it,, I will call in morning to see block number is a 4S8500x looked at a 955L block today just to see how close there were,,,,blocks completely differ not to mention the head on my grey markets motors neary twice as think as the L series.

the part number to the block is 4S8500X,,,, an my injector pump is 4S8378x I don't have my piston number with me it in my shop,,,,it has a good number on it but its not a regular looking cat number,,, when my guy at cat typed the piston number into system he said its a good number an hed showed a warehouse in Morton to be sitting on one but its not in a regular kit (with sleeve an rod an rings) needless to say its just a naked piston an when he went threw the breakdown of that part number it didn't tell him what all other serial numbers or other machine that the piston was put in. so were sitting ducks in the water here.