Buying Advice YM1110D (2T72) Head - need advice!

[gbirky]

OK all you diesel mechanics and experts...
I pulled the head off of a YM1110D (2T72 engine) because it was running poorly. I expected a leaking exhaust valve on one cylinder. I wasn't prepared for what I found. It looks like the cylinder head rusted badly inside the no 1 cylinder. I haven't removed the valves yet, but I took a digital photo of the cylinder head. I attached a small version here, but here is a link to the page on my website with the larger version.

Please take a look at the photo and give me your opinions and advice. What could have caused this damage? Do I need to replace the head? If I get the valves to seal, is there any reason to believe that the head wouldn't work OK?

Any advice is welcomed!

 

[normde2001]

Is that actually pitting that we see, or just heavily carbonized?

 

[gbirky]

That is actually pitting - or material removed by oxidation. The surface looks like it is heavily rusted.

 

[normde2001]

Had to be water getting in there, (head gasket, head or block crack). I'm no expert, but I believe I would check it over closely for cracks, clean up, valve job, head gasket, maybe shave head, good to go. For sure let a machine shop handle the head. That may be the cavitation, (pitting), caused by the wrong type of antifreeze that I have heard about on these forums.

 

[EFC]

The guys are right, it is water that ran down the open exhaust pipe and entered the cylinders through the valves. The exhaust valve seat will be bad. That is also caused by sitting for long periods of time without running and condensation builds up. It is a very normal problem with 4 cyl Mitsubishi heads. Have the head shop do new valves and seats and your good to go.

 

[gbirky]

The cavitation from the wrong antifreeze happens on the coolant side of the cylinder sleeves. There is no evidence that the head is cracked - no oil in coolant, no coolant in oil, no overheating, no mysteriously disappearing antifreeze, and no bubbles in the antifreeze. The gasket surfaces on the head and block look very clean and nice. The other cylinder is very clean and shows none of the pitting.

The only thing I can think of is if the engine sat with the exhaust valve open to that cylinder for a long time, and got moisture in the cylinder. Then the head rusted - but the sleeve looks good with some minor imperfections down low in the bore. I suppose its possible that the coolant was leaking into the cylinder, but in that case I would have expected bubbles and overpressure on the coolant side - which I didn't see.

Anybody else with ideas???

 

[gbirky]

Buck,
Thanks - you must have posted just as I was posting my last one. On these heads, the valve seat is just the head material - there is no insert. If I replace the valves - that means new guides as well doesn't it? I just need to know what parts to get.

Greg

 

[normde2001]

I like Buck's explanation. Looks like you just need to rework the head and put it back together.

 

[EFC]

The head shop will cut out the old seat and plug it with a new one then grind. You will need a new valve but every time I have had it done they just turn an oversized one to fit and hand it back to me like it is the easiest thing to do in the world. The last Mitsu head I did needed to new valve seats and new valves and it cost around 150.00 to get it done and put together.

 

[kayssupply]

I had a YM 1700 head that looked worse than that and had a crack between the valves. I sent it to a head shop that welded it and filled in the pitts and then remachined it. They said if you didn't do that the compression would be different between the cylinders. They also put the hardened seats in like Buck said. It's still working hard as far as I know.

 

[gbirky]

Buck,
Thanks. I'll take it to a shop and see what they say. Here is another photo of the exhaust port with the valve removed. It really looks bad, but they may be able to cut out the old seat area and put a new piece in. It really looks bad, but I guess it should be OK if they can work it.

 

[Anonymous Poster]

I'm no mechanic...But I'm impressed the machine was stiil running. It appears they can take quite a bit of neglect and abuse.

 

[gbirky]

It was a son-of-a-gun to get started as it only fired on one cylinder on startup. Once it was running for a while, and got some heat in the engine, the bad cylinder started firing. It had pretty good power, but smoked alot.

Anybody out there have a good used head for a 2T72? I'd prefer to replace the head with one in better shape - especially if I don't need to do such significant machining.

 

[bruce1966us]

Greg,

We do cylinder head work on a regular basis. We have only had one we could not fix and that was because someone had tried to weld it. Give me a call if interested 931 455 6999.

Thanks,
Bruce

 

[gbirky]

Here's an update. I took the head to a local machine shop where it was determined that the head is cracked between the valves - into the water jacket. He couldn't fix it - but said he could send it out for repair. He couldn't give me any kind of cost. Another shop referred me to yet another local machine shop that can make these kind of repairs. I'll take it there today to see what they say.

Bruce, thanks for the offer. I'd like to keep everything local to avoid shipping costs. I'll keep you all up to date.

What is the consensus on welding repairs on heads? Will the repaired head hold up as well as a new or remanufactured one?

 

[gbirky]

Another update. The head is at a local machine shop where I will get a firm price on repair once the head is cleaned up a little. Initial guesstimate is $250-$300.

 

[gbirky]

One more update....
I just got a call from the machine shop. The damage is a little worse than they thought. Its going to run $375 to fix the head. But it will be ready to bolt on when I get it back next week sometime.

He said the damage was from overheating. Let that be a warning to those with older YM tractors that don't have water pumps. BE CAREFULL NOT TO OVERHEAT THEM. Don't use over 30% antifreeze - though I cannot trace it back to that, I suspect that is why it overheated and cracked the head.

I'll post more photos of the repaired head when I get it back.

 

[gbirky]

I got the head back on Friday, and finally got around to taking a couple of photos. Attached is one of the photos of the repaired head. The total was $372. Originally I was told under $300, but since the shop had to do some welding down inside the exhaust runner where it had pitted badly, it ended up being more.

 

[EFC]

sweeeet! /forums/images/graemlins/grin.gif