Antique fuel injection systems on the older engines didn't change much in 70 years so it's easy to work on. My father owned an International Harvester dealership from 1939 to 1952. I still have his last service manual - it covered all tractors in one book. The diesel injection system in the 1951 WD-9 is not much different than the systems before they started improving fuel burn, but that varies by model. For example, the fuel injection pressure on the WD-9 differs little from that of my
L5740 (reference workshop manuals on both). Remembering our TD-6, TD-9, and some WD-9s dad sold, the smoke output is similar. Never have found a good cleaner to get the soot off the loader frame of the
L5740. Once when I finished talking to my partner and started my engine forgetting he was standing near the exhaust discharge, the blast of smoke from tarting triggered an asthma attack - fortunately he had is emergency inhaler. To clean the exhaust most have gone to a high pressure pump capable of about 30,000 psi (book value on my
L5740 is 2,400 psi) which breaks the droplets into a much finer size but requires precision manufacturing and clean fuel. In addition the injectors now incorporate a piezoelectric control that allows multiple injections as the piston strokes, but the simple old injectors gave one good pfft and that was it. It relied on swirling air to distribute the fire/heat that expands the air pressing on the piston. In automobile terms the old fuel system is not unlike a Model T carburetor as compared to today's individual direct injectors. Like a Model T the older diesels are relatively easy to work on but remember that black smoke is unburned hydrocarbons, the fuel you payed for, going out the exhaust. Not saying a DPF cleaning exhaust particles means all those $$$ are saved because they end up in the DPF. The DPF, however, is not capable of handling the massive amounts of soot produced by older technology injection systems. There will be growing pains just like the auto industry went through. My first fuel injected cars were 1988 and 1989 Pontiacs and the injectors were not durable but the fuel economy gain over the cars they replaced was impressive. Now my latest cars and my pickup have double the miles those first injected cars had and still no problem. So if you don't feel comfortable with a DPF, I understand there are still plenty of old style tractors sitting around. Some say, however, they command a premium price. From personal experience, however, that gas not proved to be true. When I wanted to trade my
L5740 on a
L6060, the dealer me a worse deal than he did when I traded a 10 year old
L3710 on my
L5740.
