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D8H Engine Swap

em7-300

New Member
Joined
Jan 23, 2021
Messages
4
Location
ohio
What s/n is the D4D? If it's early with the D330A (4-1/2" bore) it does not readily interchange with the 3304. If it now has the D330C engine (4-3/4" bore) upgrade to the 3304 has been done without to much hassle.
Not sure where the serial # is on these old Cats. Several maintenance plates and casting #'s but I didn't find a serial plate or number for sure.
 

em7-300

New Member
Joined
Jan 23, 2021
Messages
4
Location
ohio
Only one machine shop around that could handle the D342, and they are not cheap, but they are the best. Anyways, starting at $5K to have the block welded and line bored, another $2k to have it milled and counter bores cut. More if they run into problems. They will not weld the crank as they say it takes the hardness out, but grinding should clean it up - have another shop that can do that for a more reasonable $400.

Anyways, I am looking at $7500+ to get the block and crank fixed. I haven't even called Cat to get a price on a complete rebuild kit and pair of reman heads, but I am going to guess at least $15K. Add a few little parts and I am figuring on $25K to $30K to get it done the right way. If I had a need for another D8, that would be a good option, but I don't really need two...

Or, I can take a cheap Big Cam and 13 speed and a can of welding rod and have it running for much less than $10k.

My biggest concern is how to make the transmission oiling system work without the torque divider. I can easily handle the rest.
A lot of old Allis and Terex dozers ran Detroit Diesels that were not really all that powerful. HD-19 etc.. If you can get it coupled properly, the Cummins should work just fine. I know Cat is ahead of the rest with respect to torque but gearing should make up for that. I see a lot of scrap Cats because the engine is too expensive to repair for what the machine will be used for.
 

ETMF 58 White

Well-Known Member
Joined
Feb 21, 2011
Messages
184
Location
SEC West
So far, the vote on here is about 20 to 2 on doing the Cummins conversions. I’m thinking the majority is probably the better idea group.
 

Jonas302

Senior Member
Joined
Jan 4, 2015
Messages
1,197
Location
mn
Wait now I didn't know we were voting :) I say go for it cat engines cost to much to build so the dozer is scrap either way and I assume that you would have fun doing the conversion it would be different if you really needed it to work

By the way after rc mentioned blade plowing I had to look that up and came across a d11 with 12 cyl cummings conversion those plows must pull hard in that dusty ground
 
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Seabass77V

Member
Joined
Dec 22, 2019
Messages
7
Location
Georgia
Sounds very interesting. My grandpa swapped a turbo charged hino ranger engine into an international TD15/151 took him years to get it right but it would push like his D7G when he was done. I do remember he couldn't keep clutches in it. Such a shame the lack of parts forced him to scrap it.
Subbed.
 

Orest Anhel

Well-Known Member
Joined
Jun 27, 2018
Messages
53
Location
Dease Lake BC
Was doing some helicopter work off a neighbours property a few years back. They were placer gold miners and had a bunch of old equipment around the yard. Was walking by a D6 C (I think) and a black air cleaner caught my eye. On closer inspection there was a Ford V8 gasser with automatic transmission in it
 

Welder Dave

Senior Member
Joined
Oct 11, 2014
Messages
12,257
Location
Canada
The shop that rebuilt my 3204 rebuilt a big old Cat generator engine used on a drilling rig. I think it was 12 cylinder(might have been 8) and cost $50K to rebuild but they said would go 30,000 or more hours if maintained properly. Might have even said 50,000 hours but can't remember for sure. It's basically running the whole time the rig is set up.
 

Welder Dave

Senior Member
Joined
Oct 11, 2014
Messages
12,257
Location
Canada
They do most of their own work. They got new management when they moved to Nisku. Apparently they watch the sales staff like hawks. Old managers and good staff were either let go or forced out. I spent a lot of money there over the years. This is the place that charged me $160 to pop a sprocket off my skid steer wheel motor and wanted payment in advance. They said would take an hour. I went the next day after paying up front and it was still sitting in the same place on their counter. Guy says give me 20 minutes! It took longer only because it had to cool off enough to handle. They certainly won't be my 1st option if I can find what I need elsewhere. They did my engine, steering clutches, rotary swing motor (sent out for shaft build up) seals and repaired my stick cylinder. None of these repairs were cheap. They do good work but not the same as they were. More a recipe to lose customers.
 

zhkent

Senior Member
Joined
Apr 21, 2007
Messages
294
Location
Kansas
Occupation
Earthmoving
I like the idea of your conversion, and I would think you could fix a pump to run the trans.
To me the concern would be shifting forward to reverse without a torque converter.
That's gonna hurt. And if you use the clutch I think that would end badly.
Unless a guy came to a complete stop to shift.
If you used the clutch and did a reverse forward shift while rolling, that powershift is gonna send the clutch disc spinning backwards. Starting the clutch disc from a dead stop would maybe last quite a while, stopping the disc from spinning the wrong way and then engaging, that sounds like a lot of wear.
Had though about this once, wondering if I could lighten up a D9G. I didn't go any further than thinking about it. Would sure like to see how it goes if you proceed.
 
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