Hi, rehpig.
I'm with Gauntjoh on this one. Those pistons are around crossover with the 2 middle ones being higher in their bores than the end ones.

If #4 has metal on the sleeve, that would seem to indicate that it has 'grabbed' at some stage

The whole D4D range was one of the most bulletproof models that Cat made up to that time - and not many or much better since.

Some of the early D4Ds fitted as dozers did have frame cracking problems as they were the first D4s set up standard with the blade lift mounted on the nose like their bigger brothers.

I never did see a D4D as a bare tractor around where I lived and worked. Everybody seemed to want them to be miniature D9s.

Just my 0.02.

That's 17,844 hours. Meters read up to 99,999 or 100,000 hours before rolling over.
You will find that very few bolt ons interchange between the Industrial/Marine engine and the D4D and what does interchange, like the governor will be set up differently. What you have to work with is the basic short block.
I would recommend checking the head and the engine bearings. The D330A was not one of Cat's most durable engines and the heads were prone to cracking. Also this was Cat's venture into bearing inserts with the locating tabs rather than dowels and those wide bearing clearances that Cat's were know for resulted in spun bearings if clearances became excessive.
The turbo arrangement of the Industrial/Marine engine will not fit the D4D, location of the turbo is different and different manifold is required. At least if you choose to turbo the piston oil cooling jets are there in the turbo engine.

Dozer is home. Oil pan removed. About 2 cups of water in the bottom along with about 1 inch of sludge and about 5 gallons of oil. Crank is intact. Only deep pan is removed at this time. I don't have my books yet but it looks like I will be able to jack up the front of the engine enough to remove the few bolts left in the rear plate. I am hoping that I can at least remove that plate without removing the cross over spring at least to further investigate the conditions. I will attempt this in the morning unless someone on here tells me that that won't work. Being optimistic, may only need new sleeves, pistons, and rings. Only time will tell.

On the trip to pick up, I got to the destination only to see that the dozer was being pushed with a loader with one side of the tracks not moving. Simple fix. Brake band stuck. Loosened the adjuster and free!!!! Also found out, while looking the unit over at home that it has a oil clutch for the drive clutch. Just one more good reason that it might be a worthy find.

Full oil pan is off with jacking up the frame and removing the bolts off the crossover spring. Biggest issue now is the accessibility of the outermost rod end nuts. Unless I make a special welded socket wrench I am at a loss as to how to proceed. Thought possibly to tap on the pistons with a block of wood. All issues appear related to rusted piston rings. All else appears normal. Intentions are to replace sleeves pistons pins and rings.

Hey Robert, if you're able to rotate crankshaft ( think tooling I have that applies if starter motor is removed) . You may be able to remove liner and piston by forcing liner out of packing area then remove con rod nuts. Don't be underneath engine while doing this as you could get a bath. If you need the tooling, let me know.

All pistons and liners removed. Replacing with all new liner kit which includes piston, pin, rings, liner and seals and new connecting rod bearings (std). No real wear on the bearings but minimal cost. Will be sending head out to be machined and new valves installed. This old girl is going to run again.
Stuck engine problem was water sitting in cylinders. Number 2 and 3 were stuck tight. Liner and piston came out together. Will have to put in the press to see if I can get them to move out of the liner. Hope so.... as I believe the conn. rods are still quite good. The crank does rotate freely now and all the connecting rod bearings had great oil coverage on all surfaces.

Oil pump: I did remove this to gain access to the number 1 piston/liner. Is there a reason to break into this pump while it is off. Are there serviceable parts inside it that make sense to change while it is out. The oil pan did have a bit of sludge in it but I don't believe it was to the level of the pick up tubes.

In removing the connecting rods I struggled to locate the typical 1,2,3,4 markings on them. I have never seen before, in my limited engine work, where they are not specifically labeled. The only markings on them are a HAND ETCHED number on each cap. l will get a picture of them but the numbers are like 4.07....15.67 etc. Random numbers. No stamping type numbers on the caps. Is it weights? I do have them in the order and location where they were removed. Any one seen this before? The service book states that they should be labeled. There is a single caste tick mark on each to identify matching cap to rod but no numbering. Is it that they have been replaced in the past? What should I be concerned about? Thanks is advance for your help and knowledge!

Hi,
will await the pix before comment on etchings--sometimes are used during production for machinist ID, production line runs, batch numbers, etc.
No cylinder numbers stamped suggests replacement and/or aftermarket rods which for obvious reasons would not be ID'd for a particular cylinder--imagine getting No5 or 6 rods to fit in a four cylinder engine--although I have seen it when used rods were used to rebuild a four banger with 6 banger used parts--they still go the same.
Cheers,
Eddie B.

not sure on these old girls....but be careful on piston orientation....usually an arrow, notch, valve eyebrows...to the front(or)....and same with the rods....i'm thinking gasoline v8's....but just be certain....little details....

As I mentioned early on that is not the original engine/block in your 78A. Stands to reason rods may not be marked if supplied by rebuilder.