Hi all. I picked up a Cat 950 serial number 81J667 as a "hobby project" and I need to find a replacement engine block because the one in it came with two non-factory windows (one on each side) where it had thrown the number 1 rod. I toyed with the idea of patching the holes, both of which are in the skirt between the balance shafts and the water jacket, but upon further inspection there are some hairline cracks that are very close to where the water jacket starts, so now trying to find a replacement block. This is a "for fun" project with the ultimate goal of using it as a yard forklift and occasionally moving some dirt with it - not planning to make money with it so budget limited. As noted, machine serial number is 81J667. I have looked all over the engine and cannot find an engine serial number or engine arrangement tag (or even where it looked like one used to be). The block casting number on injector pump side is 5S5300. I read somewhere (maybe here?) that this casting number appeared on both D330Cs as well as early 3304s. It has the pump arrangement where there is an "accessory drive" with the service meter between the pump and the front cover, and the fuel lines come out of the pump in the middle of the engine front to back. From pictures I have seen of other early 950s, it appears to be correct, but the number cast into the front cover doesn't match the part number in the machine parts book (dead tree) that I have (book shows 5S6385 but my front cover has 5S5974 cast into it) so who knows... I bought an engine parts book for 78P 3304s but according to it that series engine didn't start in the 950s until a later serial number machine than mine so it is not much help. My general questions are: Can I use a non-turbo block so long as it is a counterbore (not spacer plate) block if I intend to swap cover, turbo, pump, air compressor, etc. from old block to "new" one? And does industrial vs. vehicular matter? My concern is that my engine is turbocharged and I am not sure if (1) only turbo 3304s have piston cooling nozzles; (2) all 3304s have piston cooling nozzles; or (3) no 3304s have piston cooling nozzles. Neither of the two parts books I have show or list "piston cooling nozzle" "piston cooling jet" or anything similar, so maybe not even the turbos have them? If the turbo requires piston cooling, can it be added to a nonturbo block and if so is that drilling and tapping some holes or is it $$$ at the machine shop? I found part of a Cat service bulletin online somewhere that seemed to indicate that there is a way to use a spacerplate block with a PC head - some special spacerplate that adapts from the spacerplate block oil passage to the PC head oil input passage. True? are these available? cost effective? I think I know that I cannot use a DI head because my PC injector pump doesnt make enough fuel pressure (and there probably aren't correct fuel lines available). A specific question: I found a block candidate but it is either industrial or marine and nonturbo. It is serial number 4B8359 and arrangement number 4N9960. Would this engine work if I only use the block from it and everything else from my engine?
I think the first thing you need is a Parts Manual that corresponds with your machine Serial Number. It will also contain details of the engine parts. Machines of that era fitted with D300-series engines carried the same S/N on the engine as they did on the machine, so if you can't find a S/N plate on it there is a possibility that either the cylinder block or the engine are not original. The manual you need (UE070123) covers all 81J machines from first built up to 3501. See illustration below. There appear to be plenty of that particular publication reference for sale on eBay starting from $12 upwards. FYI as near as I can determine the 3304 engine was not fitted to 950 wheel loader until Serial Numbers from 81J7846-Up (definitely) or 81J5411 (maybe).
Regarding your cylinder block. After a bit of digging it appears as though 5S-5300 is probably the original block despite what I thought earlier. That Part Number services to 8S-3711 and then to 2P-8774. The aformentioned P/N are all counterbore blocks and 2P-8774 was the last iteration of that design. Regarding upgrades in reference to the newer spacer design of plate blocks see the attached. Check the casting number on the block of this engine. It could well be 2P-8774, the last of the line in counterbore blocks. If it is then in my opinion it would fit.
Forgot to mention, your installed engine is a 4.75" bore D330C. It's far too early to be a 3304.
Nige, Thank you for looking into this - I appreciate your time. Pardon me being a little slow on the uptake here - is what I am looking at in your second attachment telling me that the jets are in the rods and fed off of the rod journals rather than from the block oil galleys, such that block provisions don't matter as far as having or not having piston cooling? I have the parts manual for the machine (UEO70123 dated July 1977 original Cat dead tree book). It doesn't list piston cooling nozzles/jets/orifices, and the drawings of the con rods don't show any orifices... D330C and 3304 are identical except the label, right? Any reason to prefer counterbore block versus spacerplate block with conversion kit if I find a good deal on a spacerplate block?
Go back and look closer. You are misinterpreting the drawing. The orifices that are mentioned are for the oil feeds to the crankshaft main bearing, not the rod bearings. No they are not although the D330C morhped into the 3304. Some parts are the same but others are model specific to either one or the other. To go more deeply into the differences you need someone with more experience than myself with the D330C engine. That's why I tried to make it clear that for sourcing parts you need a Parts Manual that covers the particular engine you're working on. If you changed to a spacer plate block there could potentially be more parts required (again you need someone more expert than me) to make the conversion apart from the block. In view of the comment in your OP - "This is a "for fun" project........so budget limited" I would suggest that you try to stay with a counterbore block. My 2c. YMMV.