Re-power D69U

It would make more sense to use a bigger Cummins, like a NH250, or later over the road engine. Still better would be to fix the original engine, or find a replacement.

Too bad we aren't closer together.
I have a D4600 with a good working pony engine (thanks to this forum).
I believe that your early crawler uses this engine.
Would trade up for your winch.
Also have all the parts to rebuild your engine if it is indeed a D4600.
Rings, bearings and gaskets.
Oh well, I can dream right.
Regards Chris

You don't mention if the tractor has an oil clutch or dry? The neat thing about the oil clutch 8/9U tractors is the modular design. You have an engine with a clutch assembly mounted in the frame ahead of a u-joint/shaft which connects to the transmission input shaft. The dry clutch has an input flange instead of a bolted U-joint mount flange, but could certainly build an adapter to a u-joint that would run true as long as space didn't get critical. The oil clutch duplex u-joint shaft is about as compact as can be made.

So if you could find an industrial engine with an over center clutch, you could fairly easily drop it in after fabricating some mounts and a new shaft. Dropping one into the frame ahead of the CAT clutch is not likely to be an easy project. Only major obstacle would be the equalizer spring mount/frame cross member.

I suppose you could make a version of an over-center clutch that you snapped over center to DIS-engage the standard Dodge clutch or maybe better, you could use the Cummins plus an automatic transmission to both get the rpm input to the transmission right and handle the clutch duties. That combo would be getting pretty long though, not sure if that would fit. Something like a marine gear might work well, but don't know if such a thing exists?

The D6 of that era was a popular ag tractor in some parts and there were quite a few Detroit diesel transplants using the ~240 hp 6-71 engine. The rest of the tractor was protected somewhat by eliminating the lower 2 gears in the transmission and the high revving detroit diesel design. Even then, I think the final drives had a tough time with extended high hp loading in ag work.

Your best plan would be to convert the engine to direct electric start and to do any repairs or replace the engine with a good one that's in better shape while you had it out. There's lots of tractors out there with the factory bellhousing for direct electric start. Some of the converted former dry clutch machines even have the direct start bellhousings.

I think your simplest option is to rebuild or replace the D4600 - anything else is going to be a hassle. The D4600 obviously fits exactly, so, if you had one that worked properly, you'd be golden
Cheers,
Neil

A Cat 318 would be easier than most to replace the D4600.I have been lead to believe the dry clutch was the same on both,just that the later ones had the cover to keep the dust out.With OM's help direct start is possible on all 318's.Many of the engine parts were available from after market sources as well as Cat. Deas had another point in the 318 in the D6 never exceeded 1600 RPM and I would think the D4600 may have been even less.
Ray

it is my understanding that the 9u's only had the d318 engine, alothough it had a few different power options through the years as it was produced for ten years. I have a 5r d6 with the d4600 and dry clutch. looks like you could bolt the d318 right in if you had a dry clutch unit. looking at my 9u's it appears you could more than likely remove a dry clutch and engine assembly as a whole unit, and replace with a wet clutch and engine assembly. I haven't compared the parts books between a 5r and a 9u. I have however combined a 9u transmission into my 5r. most of the main parts where the same, and the 9u parts that where upgrades fit the 5r case. most gears had the same part number. From my limited knowledge, I figured that the 4r/5r tractors where the same as the 8u/9u's from the flywheel back. there are a few guys out there with 8u/9u engines for sale that would be a cost effective way to fix. high idle on the d4600 is 1500 rpm, full load speed was 1400 rpm. a 5.9 cummins does around 3000 rpm. it is possible to install a repower unit into your old cat. if you used an engine tranny combination and hooked the tail shaft of the transmission to the input shaft of the cat transmission. I have a friend with a 1u d8, he repowered it with a 427 chev big block, and a th400. he said it has more power, and with the auto tranny he has a 3 speed power shift with reverse. and it burns less fuel using the v8 than the old cat diesel did. he also adapted a hydraulic pump tot he front of the v-8 and installed a hydraulic blade with tilts.

Ay chance you could post some pictures of the 427 powered D8. We would love to see it.