Case/Davis trencher backhoe

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Eugen Canada
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Re: Case/Davis trencher backhoe

Post by Eugen »

I got some good news and some bad news :109:

Rust pitting but don't know how deep. The cylinder measured around 3.25 and the piston STD confirms it. Maybe, maybe, it can go 0.030 over. 🤷‍♂️
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Case 224, 444, 644, 680E
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Re: Case/Davis trencher backhoe

Post by Eugen »

The valves are just a little gummed up. :D
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Case 224, 444, 644, 680E
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Re: Case/Davis trencher backhoe

Post by DavidBarkey »

You need to get the engine out and do a full tear down . Until then fill the cylinders with varsol and cover . let sit for couple of days and see if you have weaping through sides . That will tell you if you have a cracked block or not .
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Re: Case/Davis trencher backhoe

Post by Eugen »

I just went back and saw your comments, aren't you guys funny :rofl: :rofl: :rofl:

On a serious note though it seems like a very cool engine, I'm not sure it's worth fixing ($$) as much as I hate letting an old engine go to scrap. Missing starter, hard to find parts and quite pricey when found. Pistons and all the new stuff plus the unknown bore work? Needs to be pulled out anyway, hopefully I'll find a way to get to that last engine mount bolt.

On the other hand I'm thinking that I should better start with the backhoe, as that would be rather useful to have working even if not on the tracked chassis.
Case 224, 444, 644, 680E
Kubota B26 :blush:
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Eugen Canada
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Re: Case/Davis trencher backhoe

Post by Eugen »

Here's some more food for thought. Seemed to me interesting that both pistons are seized at about the same depth in the cylinder. What the hey, let's measure, me thinks. We know that stroke is 3.625 for this engine. But both pistons are exactly at 2.67 inches deep from the top of the block! So I did a quick search for what the crankshaft looks like. Oooh! Aaah!

Screenshot 2023-03-10 at 11.35.40.png



So this is like one big cylinder engine really! :O cool or not?
Case 224, 444, 644, 680E
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Harry United States of America
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Re: Case/Davis trencher backhoe

Post by Harry »

I would say that engine is a torque monster for sure. :peace: Harry
1973 444, 1974 644, 1976 446, 1977 646, 1986 226
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Re: Case/Davis trencher backhoe

Post by Timj »

Definitely interesting, haven't seen that before. Just like 2 one lungers coupled together. ;)
:446cart: let's go, it's finally time to blow. :peace:
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Re: Case/Davis trencher backhoe

Post by DavidBarkey »

Eugen wrote: Fri Mar 10, 2023 11:40 am Here's some more food for thought. Seemed to me interesting that both pistons are seized at about the same depth in the cylinder. What the hey, let's measure, me thinks. We know that stroke is 3.625 for this engine. But both pistons are exactly at 2.67 inches deep from the top of the block! So I did a quick search for what the crankshaft looks like. Oooh! Aaah!


Screenshot 2023-03-10 at 11.35.40.png




So this is like one big cylinder engine really! :O cool or not?
Yes and no . I would say if you look and the cam the lobes from one cylinder to the next are 180 degrees out from each other . They may be both up or both down but they will be 360 degree apart in the firing order . A four stroke takes 720 degrees to make one full cycle . Like the Onan Horizontal twin . While both go in and out at the same time they are both not firing at the same time .
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Re: Case/Davis trencher backhoe

Post by Harry »

I had a Lincoln Welder powered by a thd Wisconsin engine. Both went up and down at the same time but as David mentioned the firing was opposite. It was a hand crank magneto start. I sold it because I wasn’t using it anymore. :peace: Harry
1973 444, 1974 644, 1976 446, 1977 646, 1986 226
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Re: Case/Davis trencher backhoe

Post by Eugen »

As I said, it seemed to be a good idea to start taking the backhoe off. It attaches to the machine with four big pins. Was able to take the upper two off, but had poor access to the lower once below the machine. Plus the backhoe seems to be really heavy. Decided to start taking it apart. It was a beautiful sunny day. The snow is still not melted, so it was really hard to get the 644 there to help me lift the backhoe. Got stuck several times.
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It didn't go fast. This thing must've been out in the open for many years. Pins, clips, everything severely rusted. Sprayed most parts since yesterday with rust spray, but still was hard. Eventually got the dipper off. One silver lining I guess, clean red oil came out of the bucket cylinder. With it off I lifted it up with the 644 and thought, off I go.

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Didn't happen, as I got stuck in the snow. No matter what I did, chains under the tire, pulling with the 444, nothing worked. I gave up and unloaded the dipper and moved back pushing myself with the loader bucket and then just dragged the dipper along to where I had more traction where I could lift it up with the bucket and bring it next to the work area.

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It was around 4PM and I went in to spend time with the kids, then a long walk with the family, dinner, kids to bed, and it got 10:30 or so. Thought I would end the day with a bang. It turns out it was more than one bang, as I wrestled two big pins. Once they came out I was able to pull the cylinder a little away from the dipper body and clean the gland area. I do not have this type of wrench, so now I'm looking.

E5287156-1BFD-4712-A39B-9E640BFA2167.jpeg
Case 224, 444, 644, 680E
Kubota B26 :blush:
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