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Re-power D69U

Re-power D69U

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MetalmanD69U
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Want to ask for opinions here;
What do you think about re-powering a D69U with a 12 valve Cummins diesel out of a Dodge pickup?

I have two '9U's, one is early 1950's with the original engine, winch, hydraulic straight blade, decent undercarriage etc. and the pony needs rebuilding, but it will still start the diesel. I want to sell this machine.

The other machine was put together from spare parts, it is 'mostly' from the '50's, hydraulic + 'C' frame, winch, excellent undercarriage, but has the 6 cylinder diesel from the 1940's, and is quite low on power. The pony on this one is locked up, I assume the pistons have seized in the cylinders. Back when it did run it was very low on compression, barely had enough power to spin the diesel.

It just seems like a sensible solution to convert to the Cummins. They are plentiful, easy to find parts for, and electric start.
I like the old Cat bulldozers, but would prefer to have one that I can hop on and use for small jobs once in a while, and not have to tinker for half a day to get it running. The machine will sit for months between uses. One fellow I mentioned this idea to said that the Cummins does not have enough mass, even if the torque numbers of the Cummins do exceed those of the 1940's Cat diesel.

Any educated opinions out there?

Thank you.
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Mon, Oct 7, 2013 2:11 AM
STEPHEN
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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.
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Mon, Oct 7, 2013 3:14 AM
snowshoveler
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Reply to STEPHEN:
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
193? d4400 cat powerunit
1950 john deere M
1959 international t5 crawler
1977 powerking 1216 tractor
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Mon, Oct 7, 2013 3:57 AM
Deas Plant.
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Reply to snowshoveler:
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
Hi, MetalmanD69U.
IMHO, you would need to use an engine with similar horsepower (A slight upgrade won't hurt.) and torque characteristics at around the SAME revs as the original D6 engine. Many later engines operate at somewhat higher revs to achieve their power and torque and installing an engine like this could have you driving a tracked go-cart rather than operating a serious dozer. It would also increase track wear and make it a bit harder to control the machine for any serious trimming work.

Too much power might also be a problem. As I understand it, the later D6B used pretty much the same back end as the 8U-9U tractors but with a bit more 'grunt' and they had some back end/final drive failures which were not all that common in the 8U-9U machines with the lower horsepower.

I do agree though that it is nice to be able to decide that you want to do a bit with a machine and just hop on and go do it.

Just my 0.02.
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Mon, Oct 7, 2013 4:31 AM
ccjersey
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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.
D2-5J's, D6-9U's, D318 and D333 power units, 12E-99E grader, 922B & 944A wheel loaders, D330C generator set, DW20 water tanker and a bunch of Jersey cows to take care of in my spare time😄
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Mon, Oct 7, 2013 6:18 AM
neil
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Reply to ccjersey:
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
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Mon, Oct 7, 2013 7:07 AM
Ray54
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Reply to neil:
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
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Mon, Oct 7, 2013 9:55 PM
MetalmanD69U
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Reply to Ray54:
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
Quick note to say thanks guys for the excellent replies.
Both of my tractors have the dry clutch by the way.
Have to get to work, more later.
Regards.
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Mon, Oct 7, 2013 10:12 PM
rmyram
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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.
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Mon, Oct 7, 2013 10:20 PM
old-iron-habit
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Reply to rmyram:
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.
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Tue, Oct 8, 2013 2:00 AM
MetalmanD69U
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Reply to old-iron-habit:
Ay chance you could post some pictures of the 427 powered D8. We would love to see it.
STEPHEN; that's a good idea, I had'nt thought of that. There should be lots of those around, though I guess I would have to be careful not to overpower, some of those rigs have a lot of h.p. and torque.
snowshoveler; thanks, but I have my heart set on electric start
Deas Plant; good points, and I agree, the hp and torque/rpm should be similar to the D318 that my machine should have!
ccjersey; thanks for the suggestions, I like the idea of a transmission between the re-power and the dry clutch.
Neil; you are right that would be the simplest, I am hoping to end up with a bit more power than the D4600 has, and the D318 should be a bolt in (I assume)
Ray54; I agree on the D318,, but have not seen one of those for sale. Have been keeping an eye out for one of those for several years.
I replaced the clutch 10 years ago on the 4600 equipped machine, ordered all the parts using numbers for the 318 equipped machines, and it all fit.
rmyram; I think you are right on that, but this machine was assembled from parts by an old catskinner (Ole Olausen) who used to log in this area.
Comparing the 4600 equipped machine to my other one with the D318, pretty well everything is identical.
As far as I can tell, everything except the diesel is from the fifties. I first discovered that the engine was not for a '9u when I tried to source an exhaust manifold, the one I ordered obviously did not fit so I sent it back. I ended up welding the cracked manifold, and never did get my money back!

I hope to get to work on the engine issue before the snow flies, will keep posted.
Thanks again for all the help.
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Tue, Oct 8, 2013 12:59 PM
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