CAT 246 Engine repair

I bought a 2000 CAT 246 that needed to be repaired. Broken rod, hole in the block, basically total failure.
It has the CAT (Perkins) 3034 4 cylinder turbocharged diesel engine.

It requires a block, at least one rod and a crank or crank repair that involves welding and regrinding.

Sourcing parts has proved to be a major problem. CAT wants 12k for a long block. There are several on eBay at that same price, Drews salvage has a rebuildable core for $6,500. All off those are out of the question, I'll cut my losses and part the machine out before spending that much.

One option I am trying to explore is, using a naturally aspirated Perkins 704.30 from a Daewoo 1760XL skid steer.

Perkins number for the CAT engine is 704.26 family is "UB"
Perkins number for the Daewoo is 704.30 family is "UA"

CAT block casting number is 3711H09A/4 HP rating is 74? I believe?
Daewoo block casting number is 3711H09A/1 HP rating is 63? I believe?

As you can see the only difference in the casting numbers is the last digit.

Both motors are 2.9l, visually from an external comparison, the blocks seem to be identical with two exceptions.;
1. The CAT 3034 has a threaded hole for the engine oil dipstick. the Daewoo has a pressed in dipstick tube, located a bit higher on the block. The emboss is still there on the Daewoo block, just not drilled and tapped.

2. The oil drain from the turbo back to the block is the same situation. The CAT 3034 has a drilled and tapped hole for the turbo oil drain. The Daewoo only has the emboss.

I can purchase the Daewoo short block including rotating assembly for under 1k.

My thinking is to recondition the Daewoo short block, then use the cam, injection pump, cylinder head and turbo from the CAT. I have no way of knowing if the turbocharged engine used more robust pistons, rods and crank, but hopefully the rebuild parts from the CAT kit (including pistons) would work in the Daewoo.

Am I crazy for considering this as an option for a personal use machine?

Looking for some constructive feedback, thank you.

https://es.ruttsmachine.com/assets/pdf/literature/es/Perkins-Engine-Number-Guide.pdf

There ARE a lot of if’s.. but 1k vs 6500... you’d almost b crazy not to try..
Just make sure to lock the timing on your old injection pump if it has a locking bolt..

thepumpguysc said:

There ARE a lot of if’s.. but 1k vs 6500... you’d almost b crazy not to try..
Just make sure to lock the timing on your old injection pump if it has a locking bolt..

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Thanks , I was thinking the same thing.

My CAT has the 704-30T UC motor, the Daewoo is a 704-30 UA motor. The specs are identical. I think the donor from the Daewoo can be made to work.

It would be good to document for progress as there are a lot of those out there with rods hanging out

The “T” stands for TURBOCHARGED..

There are a lot of those with that issue. I would be curious what the machine is worth as a parts machine. If you could get 10K out of it as it sits, I would take your 10K and use it (with some additional money) to get some thing else. It certainly isnt worth an OEM replacement engine, but putting a non oem engine into can suck as well. Those Frankenstein machines can be a PINTA.

Somewhere here on the forums someone swapped in a different engine and wrote about the whole procedure. Without looking I don't remember what engine he used. I had the same thing happen with my 248, I was able to convince Caterpillar to give me a long block and I paid a local heavy equipment mechanic to swap it for me.

I'd say you don't have much to lose. Maybe back the screw off a little if anything, no idea what that would involve on that fuel system, maybe just back off the RPM a couple hundred?

Find a Perkins dealer

Recently installed one direct from Perkins off boat with slightly newer emissions as a running complete with fuel system for $6800

Was really affordable

The last pictures show a 404 series but the OP has a 704 series which is a totally different engine.

My question is what is the history on the Daewoo setup? At first I was thinking it was a running take-out but then you said short block so that makes me wonder.

What I was thinking originally was a running take-out that was non-turbo and save all the time and aggravation of swapping parts, just put it in and have less power. Who cares, a skid steer seldom runs at full power anyway in my world, mostly used for maneuvering things slowly.

If it has to be a short block, then beware that the pistons can be different, or they might be the same. I would just compare the volume of the piston top combustion chamber between the toasted engine and the good short block and if the same, go ahead with your plan with the head, camshaft, etc.

If it looks like the piston tops are lower compression on the turbo motor, then I guess you have more work to do and decisions to make.

Jonas302 said:

It would be good to document for progress as there are a lot of those out there with rods hanging out

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I can do that, if the group thinks it would be beneficial.

thepumpguysc said:

The “T” stands for TURBOCHARGED..

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Yep.

KSSS said:

There are a lot of those with that issue. I would be curious what the machine is worth as a parts machine. If you could get 10K out of it as it sits, I would take your 10K and use it (with some additional money) to get some thing else. It certainly isnt worth an OEM replacement engine, but putting a non oem engine into can suck as well. Those Frankenstein machines can be a PINTA.

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If I could get 10k for it, I would definitely part it out. The machine has a few things going for it;
1. It has the Loegering track system installed on it with fairly new tracks.
2. It spent it's life with one concrete company (not a rental machine).
3. That company used Michigan Cat for all of it's service.
4. Most of the major hydraulic components have been replaced by CAT within the past (4) years.



Don't get me wrong, it still has a few warts, but to put back into service for personal use, I think it's a good candidate.

Delmer said:

I'd say you don't have much to lose. Maybe back the screw off a little if anything, no idea what that would involve on that fuel system, maybe just back off the RPM a couple hundred?

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The bore, stroke and compression from both engines is listed as identical, I think it would be fine "as is".

Zkdiesel said:

Find a Perkins dealer

Recently installed one direct from Perkins off boat with slightly newer emissions as a running complete with fuel system for $6800

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Perkins wants 12k, mines a different series of engine. CAT was a bit confusing in the way they applied their own identifications, to third party supplied motors, but yeah, yours and mine are very different.

Birken Vogt said:

The last pictures show a 404 series but the OP has a 704 series which is a totally different engine.

My question is what is the history on the Daewoo setup? At first I was thinking it was a running take-out but then you said short block so that makes me wonder.

What I was thinking originally was a running take-out that was non-turbo and save all the time and aggravation of swapping parts, just put it in and have less power. Who cares, a skid steer seldom runs at full power anyway in my world, mostly used for maneuvering things slowly.

If it has to be a short block, then beware that the pistons can be different, or they might be the same. I would just compare the volume of the piston top combustion chamber between the toasted engine and the good short block and if the same, go ahead with your plan with the head, camshaft, etc.

If it looks like the piston tops are lower compression on the turbo motor, then I guess you have more work to do and decisions to make.

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I should know more as to the condition of the Daewoo motor today. The yard I'm dealing with actually has two of them. Both were being offered as cores, no claim that either one would run. The day I was there, the cylinder heads were still in place. One of them, the valve cover was loose, and it was apparent water had gotten inside of it, it was froze up. The other one was sealed up tight, red plastic plugs in any opening that would let water in. Valve cover was still bolted down. It was free and would bar over. That is the one I told them to pull the head off of, so I could get a closer look.

I can absolutely do some volume comparisons on the pistons, as well as pin to deck height, pin to pin on the connecting rods, etc etc

That brings me back to my question. If the one that is all sealed up runs good, why take it apart at all? Put it in and run it as non-turbo. I doubt you will notice a difference for a home use machine. Unless you are running high power attachments or moving large piles of heavy, loose material long distances.

Birken Vogt said:

That brings me back to my question. If the one that is all sealed up runs good, why take it apart at all? Put it in and run it as non-turbo. I doubt you will notice a difference for a home use machine. Unless you are running high power attachments or moving large piles of heavy, loose material long distances.

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The first things that come to mind, would dealing with fabricating a different intake and exhaust system for the normally aspirated Daewoo motor. The turbocharger is integral to both of those on the CAT turbo application. The Daewoo had neither an intake manifold or exhaust manifold on it.

But it would definitely be a possibility. I should know more later today.

Staggerlee said:

The Daewoo had neither an intake manifold or exhaust manifold on it.

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That is a bummer then. I would rather scare up the manifolds if they can be found than to open up a good running engine. But I could go either way on this one since the fab work to make it fit will be significant and keeping it original is always a good plan.

Well, I finally heard back from the yard that has the two "core" motors.

Apparently the one that was sealed up well, had a cracked block. So that leaves me with the one that had the loose valve cover, the only good news there is the rocker arm shaft was missing so all the valves were closed.

At this point, beggars can't be choosers. All they will state as to the condition is they guarantee the block, crank and rods to be machinable. I'll pick it up this afternoon, get it home and map out a plan.

I other news, I found the service manual from Perkins for the 704-__ engine family. There are some differences noted between to UA and UC motors, but one of those will be addressed with the new pistons, the other most notable one has to do with the heat treating of the crankshaft. But again, it's a compromise I'll have to live with.

I'll attach snips of the manual.

Remember, "UC" is the CAT 3034 (turbocharged). "UA" is it's normally aspirated brother. "UB" is a smaller displacement variation.

just a question- why do these engines fail or did i miss something? another note- turbo engines usually have a steel insert for the top ring lands and use a keystone top ring to aid in longevity but i'm not sure about these newer small engines

56wrench said:

just a question- why do these engines fail or did i miss something? another note- turbo engines usually have a steel insert for the top ring lands and use a keystone top ring to aid in longevity but i'm not sure about these newer small engines

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I'm not sure, to be honest. In reality mine's a high hour machine, the oil pressure sending unit was broken (picture above shows the spade connector, missing from the sending unit) . I believe the idiot light in the cab was probably on all the time and the previous owners were ignoring it. When that main bearing spun, it lost oil pressure, if the warning lights were in proper working order the machine should have been taken out of service. At that point it would have needed a rebuild, but the block, crank and rod would have been serviceable.

I will be using pistons for the turbo application for the rebuild.

It was my impression that the smaller 404 series, which is a Perkins Shibaura based unit, is the one that has more failures in Cat skid loaders. Model 3024 I believe. This is a 704 which has no relation. The 404 is an engine design that Perkins just borrowed from IHI Shibaura, that Cat uses because they own Perkins. The 704 may be an original Perkins design or come from somewhere else, but it has nothing in common with the 404 that I can tell.