The Old Leaking Cylinder Head, Or is it?

[PJBX]

I bought a Case IH 275 at auction, sight unseen (is there any other way to buy?).
Got it all back together and firing up. But it's only running on 2 cylinders, so digging into things a bit, I noticed exhaust coming up through the crankcase. Ah hah, cracked cylinder head (I thought). So I pulled off the head, cleaned it up, no cracks whatsoever. It's very clean. Only 400 hours.

Then I remembered the bottle of ether next to the seat when I picked it up.
And looked into the prechamber design of these tractors. It looks to me like the 2nd cylinder sustained some explosive damage somewhere in the prechamber, that allowed a pathway from combustion to the crankcase. Of course, the Mitsubishi manuals say the prechambers are not serviceable.

So now, I'm considering my options. I've seen no listings for these heads anywhere. I've got it running in a rednecky way, with the 2nd injector pushing fuel back into the fuel tank, and the vent from the crankcase to outdoor. It smokes some (but not a lot since there's not fuel or combustion in 2), and the tractor runs much smoother than I would have expected.

Anyone have any suggestions? I'd like to narrow down the problem more before giving up on it, but it's looking bad to me.

Jim

 

[560Dennis]

I’d say I would have to see what the cylinder damage is .
either not good , I would say the pre ignition forces of either bend the connection rods also due to the timing being off on the fuel Igni . So important to check everything you can.
interesting project ,good post ,
all Isn’t lost , been worse for sure , let’s see what you see ,go from there .

 

[PJBX]

Thanks Dennis. I've inspected the valves and push rods (visually), and they are all in tact. The initial gaps were the same on all the valves (loose out of spec), so most likely these are OK. The initial symptoms are: smoke out the valve cover, and zero (and I mean zero) compression on #2. Air barely hisses as it comes out and travels up the push rod opening. When I initially started it, it was burping oil up through the push rod opening up onto the valves. And black smoke. So I think the 2 was occasionally firing. I am thinking of some ways to narrow down the location of the leak to: 1. down in the cylinder with the precup taken out of the picture 2. leaking directly from the precup into the crankcase. The second case seems likely based on what the head looked like. When the head was off, the cylinders, the pistons, and the head surface were all in excellect condition. It's still a little mysterious. I should be back to it later this week. Jim

 

[BarnyardEngineering]

Have you done a leakdown test on the bad cylinder? You get the cylinder on TDC, pressurize with shop air and listen for leaks. Air coming from the intake indicates an intake valve, from exhaust indicates an exhaust valve, out the crankcase usually indicates leakage past the rings.

That tractor is pretty much an orphan, so finding parts is going to be a long and frustrating process. If you ever manage to find parts.

 

[used red MN]

Hello PJBX, welcome to YT! What do the cylinder walls look like? Broken rings and cylinder scoring are far more common failures that push compression into the crankcase. Did you run the piston down to the bottom when you had the head off and look at the cylinder? “Got it all back together and firing up?? What state of disassembly was it in when you got it? Usually a pre combustion engine has glow plugs. Pull that out and clamp a flat plate to the head with a chunk of rubber under it (old chunk of inner tube) and blow pressure into the glow plug hole with a rubber tipped blower. If there is damage like you proposed the pressure will come out of the area the push rods pass through. How about some pictures of the damaged pre-cups.
Dennis’ wording/spelling is not quite on the mark. He means “connecting rod” that is connecting the piston by the wrist pin to the crankshaft. An engine would have to suffer a serious overdose of staring fluid to bend a connecting rod, could happen. What kind of experience do you have with engine work?

 

[PJBX]

When I got it it needed: new cooling package, pump, radiator, new alternator, new battery cables, battery, etc. Normal oil change and other stuff just to get it started. Yep, did the leakdown check on all three cylinders. Two hold pressure well (1 and 3 of 4 cylinders). The second cylinder does not hold any! It's as if the air is just coming right out the side of the engine (into the push rod area). When I had the head off, there was zero scoring on the cylinders. I don't think the rings are broken. I'm pretty sure this isn't normal blowby. I have some experience with engines. Lots of motorcycle work, an old Deere tractor, and other stuff. I'm also an engineer and hobby machinist. I want to zero in on exactly where it's leaking. Then decide whether I could do something, or just push the whole thing off a cliff. It's definitely an orphan. Too bad, it rides nice, and works fine otherwise (lots of nice features, all seem to work). But it was not taken care of, and has a lot of weather damage. I'll take some shots of things when I get the chance. Thanks for all your input everyone.

 

[560Dennis]

Thanks Dennis. I've inspected the valves and push rods (visually), and they are all in tact. The initial gaps were the same on all the valves (loose out of spec), so most likely these are OK. The initial symptoms are: smoke out the valve cover, and zero (and I mean zero) compression on #2. Air barely hisses as it comes out and travels up the push rod opening. When I initially started it, it was burping oil up through the push rod opening up onto the valves. And black smoke. So I think the 2 was occasionally firing. I am thinking of some ways to narrow down the location of the leak to: 1. down in the cylinder with the precup taken out of the picture 2. leaking directly from the precup into the crankcase. The second case seems likely based on what the head looked like. When the head was off, the cylinders, the pistons, and the head surface were all in excellect condition. It's still a little mysterious. I should be back to it later this week. Jim

My pleasure pjbx
may I add investigate the starter ,bendix ,and ring on flywheel . With either that starter system has taken some big wollops try to start that engine. I think you will surely have to find the reason they were using either and correct that .
good hunti press ahead