I am looking for an engine arrangement number for a tractor recently aquired. I know it is a 4G series D4 with a D4400 from around 1939. It has the large PTO drive pulley on the back. What is perplexing is the duplicate SN tag on the side of the block where the arrangement tag should be. It shows #4G9986 just as it does on the rear of the machine. Right below where the head meets the block near the back cylinder, the number 435 has clearly been punched (not cast) in the side of the block, pictured.
I ask this because I consider new sleeves for the engine, it is stuck with some pitting. Does anyone have experience with this? How much pitting is too much? I am looking to make this an operational tractor. Not to farm with but maybe pull an old plow at local events. Thoughts?
 

  the serial number tag has been refitted .give the origanal tag spot a clean and see if there the number there ?

Those early D4's did not have an engine arrangement number, they just used the serial number. Any pitting is not good, oil will get past the rings and it will puff blue smoke.

That makes sense. I hope the unabtanium parts Gods will be kind in my quest to find what I need. Furthermore, I hope I can relay what I need to the correct channels without an arrangement number. I am assuming that Florin tractor is the best place to start? My further exploration has indeed prompted me to do what I should have done initially. A good power washing. The allure of experimental mechanical surgery on the new D4 got the best of me.

A lot of the early tractors like the 4G as it was quicker to replace the engine and put back to work than have it sitting around not earning its living.

I also have a dead 4G with different numbers front and back.

As for the pitting in the bore, I would replace them as Rome K/G said as it will damage the rings too.

As for parts I would stay to obtain the quickly as they are getting harder to get as i have heard Florin Tractors are closing next year.

Regards

if you have part numbers i have found the dealer helpful. they were at least able to give me availability and price. and some pn had changed due to updates and they were able to give the new pn. ive also head some success with a google search of the part numbers. get a parts book for that serial range and go from there. the internal parts for any of the engine series are generally the same its the bolt on accessories such as manifolds and water pumps, generators etc that can be different.

The Cat serial number book tells me your D4 was built in 1938, and I'll assume late in 1938 because your serial number is about 13 from the end of that early RD4 / D4 run starting in 1936, the last tractor was 4G9999, they then went to D4 7J series in 1939.

Without actually seeing your liners, it is difficult to give you accurate advise, but if you are only going to use the old girl at local events every now and then, my advice is to try the cheap and easy fix first, so get her freed up gently, rotating the engine in reverse can be a big help, with lots of loose juice. You can also make up a 50:50 mix of diesel and engine oil, put a couple of cups in each bore, drop a old rag in the oil to act as a wick, and light them up, they should burn for 30 minutes or more, and is very entertaining at night. This will really heat up the pistons and engine block, getting everything moving.

Once the engine is loose, get each piston at bottom dead center in turn, and put a good bead of thick grease around the top of the piston where it meets the bore, and give that cylinder a good hone, scrubbing the bore clean when you are done, the grease bead will prevent the honing trash from going past the piston.

If the head gasket looks OK, give it a good smear with Aviation Gasket Sealant and refit the head using the old gasket after you have given the valves good lapping, if the old head gasket looks dodgy, buy a new one, they used to be cheap, like about $60, current price here in Australia is around $US90 from the Cat Dealer. Florin Tractor are brilliant, they might have some aftermarket and genuine gaskets in stock, part number is 4B3052.

Original gaskets would have been copper, the current one's sold by Cat are steel, my advise is to use some Aviation Gasket Sealer on a new steel one too, I've rebuilt two of those old D4 engines, the new steel gaskets can slightly weep initially, you will definitely need to retorque your head after running the engine for an hour or two.

These early Cat diesels are considered low compression engines, and they were way over engineered compared to modern diesels, you have lots of rings on those D4 pistons, 4 compression and 2 oil scrapers, so unless your bores are shocking, I'd give her a good flogging on a heavy plow for a few hours and see how much oil she burns at the end of a couple of days, you might be pleasantly surprised she only burns a quart or two, big deal, cheaper than a full engine rebuild.

The reason I suggest you go down this path is because those D4 liners are often not available to buy, I've bought 8 for my engines and got the last stock from the Cat Dealer at the time, secondly, once you open a engine up, you nearly always take a lot longer, and spend a lot more money than you expected, getting it buttoned on up again, heading down a rabbit hole of crankshaft grinding, and then trying to find undersize bearings, and maybe replacing the camshaft, and worn timing gears.

These old Cats will often start easily, and run great even when badly worn internally, just make sure you have decent oil pressure, anything over 4 pounds at idle was good, and that you have a good thermostat, something around 190F - 195F, the diesels need to be warm. Keep it simple, and cheap, is the best advice you can get right now, if you were going contracting with the tractor, doing 2,000 hours a year, that's different, but your tractor will be lucky to do 20 hours a year.
Good luck
Mike

This is some great advice and input. I think it will get me started well on my way to getting her back to life. I love the idea of heating up the cylinders to help break them loose. I plan to give it a go. New liners aren't necessarily my last resort but having done many projects where I fixed way more than necessary, I am constaintly aware not to go down that road.

The head and valves look fine as does the original copper head gasket. With a good cleaning and some copper sealant it will be fine. The engine appears to have never been apart and still had the original gasket between the head and pony motor. The only perplexing thing were some broken valve springs for some reason. I was able to procure some good used ones. Here are some pictures of what I am working with. The engine was stuck in this position so what is under pistons 2 & 3 will be a suprise. 

I would hone those cylinders now, before trying to roll the engine, and doing the lighting the wick trick, then hone it, then gently try and roll the engine backwards, cleaning the cylinder walls as the pistons drop, that will help protect the rings better. Is there any lip at all at the top of the ring travel in those cylinders?

That number stamped on the block, suggests to me that engine has been worked on at some stage in its life, I have a engine here stamped in a similar way, I think they are workshop repair stamps, perhaps the head was pulled for a valve grind, or a full engine rebuild. Keep in mind your tractor is over 80 years old, and might well be on its second or even 3rd set of cylinder liners, and piston rings, and valves, unless you know the full history of that tractor, assume it has done a lot of hours.

Some people anneal a good used copper head gasket before reusing them, its not hard to do, you sound like a smart fella, just follow that KISS principle, Keep it Simple......

Worse case scenario, you get her running, and after a couple of days flogging her hard, you discover she burns 2 gallons of oil a day, OK, hunt around and find your new cylinder liners, seals and rings first, then pull the head and sump off, do the repairs, get on with your life, but you might get lucky here, my option will cost you a can of copper head gasket spray, $20, pretty cheap roll of the dice.