YM226D Project

[rScotty]

What grade oil? 15W40 that is thick or SAE 30 being a tad thinner? 5W30 may be useless to test with wet.

I'd use the more viscous oil. Not too much; a couple of squirts ought to do it. There isn't a lot of room in the compression chamber of a diesel & you don't want to bend a rod.
Also give a little thought to oil as fuel. Hopefully this test will increase the compression - and there is a point at which lube oil and diesel fuel start to look similar to a diesel. If you can ignite it, chances are the diesel can too.
rScotty

 

[tc197]

Ran the wet compression test today and got improved results - 350 psi in all three cylinders. So I went from 280-250-250 to 350-350-350. I think this demonstrates that the rings are not sealing well enough to maintain proper compression, however I'm not sure I can only blame the rings as there may be a secondary issue as well.

 

[tc197]

Managed to squeeze the tractor into the overfilled garage. Hoping to get the head off and see what I’m working with in the next few days.

 

[tc197]

Still here, just slightly delayed. Opening it up any day now.

 

[Smokeonthewater]

How much run time have you put on this thing? If it sat a long time, you might consider working it pretty hard for a few hours w good fuel and fresh oil... you may find that the compression numbers come up just from that....

 

[tc197]

Behind schedule but making progress. I pulled the head the other day and got my first look inside. In general things appear to be in good shape. The only noticeable thing to me is that 1 valve is discolored compared to the others. I have 1 valve that is a greyish color and appears dry while the other 5 are darker and almost look wet. I'll try to post some pictures later.

 

[California]

...1 valve that is a greyish color and appears dry while the other 5 are darker and almost look wet. I'll try to post some pictures later.

Sounds burned. Pour a little solvent in the intake and see if goes right through that one.

 

[tc197]

Been working on the tractor a bunch and overdue for an update here.

After removing the head and getting my first good look at everything I decided I was going to pull the pistons and inspect the rings, sleeves, etc. Unfortunately everything I've found doesn't look good. I removed the oil pan to access the bottom end and remove the pistons and found huge chunks of metal and a ton of fine metal in the oil pan. Something exploded, although it's not clear what yet. I had pieces that were 1/4" wide and 2" long sitting in the oil pan. At this point I knew the work was only getting started and wouldn't be a quick fix.

I got the pistons out and found some damage on the skirts and a bit of wear on the middle piston/sleeve. Everything is accounted for so far and I haven't figured out what turned to shrapnel in my oil pan so I decided I just need to pull the engine completely and go through everything. Last night I split the tractor at the clutch housing and got it into two separate pieces. Following the manual instructions, next I will separate the front axle from the engine and I'll get it on a stand so I can continue disassembly and figure out what's damaged. Looks like this project is still just getting started.

 

[bmaverick]

Been working on the tractor a bunch and overdue for an update here.

After removing the head and getting my first good look at everything I decided I was going to pull the pistons and inspect the rings, sleeves, etc. Unfortunately everything I've found doesn't look good. I removed the oil pan to access the bottom end and remove the pistons and found huge chunks of metal and a ton of fine metal in the oil pan. Something exploded, although it's not clear what yet. I had pieces that were 1/4" wide and 2" long sitting in the oil pan. At this point I knew the work was only getting started and wouldn't be a quick fix.

I got the pistons out and found some damage on the skirts and a bit of wear on the middle piston/sleeve. Everything is accounted for so far and I haven't figured out what turned to shrapnel in my oil pan so I decided I just need to pull the engine completely and go through everything. Last night I split the tractor at the clutch housing and got it into two separate pieces. Following the manual instructions, next I will separate the front axle from the engine and I'll get it on a stand so I can continue disassembly and figure out what's damaged. Looks like this project is still just getting started.

Do any of the parts in this 3T75HA rebuilt kit look to be a 1/4-in x 2-in part?

 

[tc197]

Do any of the parts in this 3T75HA rebuilt kit look to be a 1/4-in x 2-in part?

Great video, but no I don't see anything resembling it. I really need to figure out how to post pictures here.

 

[tc197]

I think these pictures worked? The second picture is a sample of some of the metal I pulled out of the pan. There is also a lot of fine metal. I'll add more tomorrow.

 

[bmaverick]

Great video, but no I don't see anything resembling it. I really need to figure out how to post pictures here.

Drag and drop or click on another web page, copy image and past. Way better than it was before. Not sure with smarty pants phones though.

 

[bmaverick]

View attachment 706093View attachment 706094View attachment 706095

I think these pictures worked? The second picture is a sample of some of the metal I pulled out of the pan. There is also a lot of fine metal. I'll add more tomorrow.

WOW. That's a lot of metal pieces to be found in the pan.

Looking at the head image by clicking on it and then clicking a 2nd time to zoom in, all looks fine except the top far left area above the cylinder area. Just a tad higher than the gasket surface, I see what looks to be a crack.
The good thing is, that crack is NOT on the gasket area, BUT, still needs tending to for welding or hot liquid steel filler. Yeah, it's a pain getting all those things out of the head and having it dipped clean. Now, I can be totally wrong, and the crack has nothing to go wrong in the future.

How do the cylinder sleeves look on their walls, bottom and top edges? Smooth, clean and no visible marks is a great thing.

Due note, everything on these machines is METRIC. Digital calipers would be real handy to check parts and clearances.

Whatever you do, try not tot mess with the engine governor or the governor rod-link. Even with re-assembly, do not apply pressure to move it out of the way, gentle get it where it should be.

On my previous JD850 (aka YM2500) the Yanmar 3T80 had a crack literally in the head of the cylinder circle. No possible way to fix.

That's when I went looking for a new head. Searched the entire North America region, learned much about John Deere 50 Series, and then kept getting Yanmar turning up. I was like, why is this happening. Found Fredricks, they had a head, but the place to rebuild the JD850, with the head, and getting it all running right was $1,000 less than getting a YM2500 or YM2610 totally 100% RESTORED to new like condition. I would have a machine with a great engine, but everything else decades old.

The good thing is, your parts so far are not destroyed. The middle piston crank-rod was snapped in two. Your image is far better. Less damage is GREAT.

If you elect a rebuild kit, align the rings just like the current engine rings on the pistons. The reason being, the rings allow a certain amount of engine oil to help lube the cylinder walls while the engine runs. Or, should the kit already have the rings on the pistons, turning them to position is rather easy.

Yes, keep us posted on the progress. There are many members here who have wisdom and knowledge with getting things rebuilt. Even folks on the Yanmar Tractor Owners Group too. So, don't be shy, ask away.

 

[tc197]

Thanks for all the info as usual. I looked into the potential crack but I don't see anything so I think that crisis may be adverted. The cylinder sleeves are tough to see but I attempted to take some pictures and I think better pictures of the piston damage will help show the potential sleeve damage. Measurement is not a problem - I have access to top notch metrology equipment and work in this field. Thank you for the governor heads up - I will try to avoid it. I am going to try and upload some videos to give better visuals of the head as well as the pistons and rods/caps. I attempted to upload the sleeve pictures in order to match the video of the head and the pistons. The first two sleeve pictures match up to the first piston in the video and the first valves in the head video. The first location is the cylinder furthest from the drivers seat.

 

[bmaverick]

Bravo, nicely done! You must be an engineer.

Each group of piston+rod are a little different, none are the same.

The last piston+rod was interesting. The 2 halves holding the bearing had score marks, yet the rest of the piston+rod looked the best of the bunch.

The middle piston head sure looked like trouble with the piston sides mared up symmetrically. That is a real puzzlement.

The rings on each piston tell the story really well. Should the rod or bearing be out of scope, the rings would wear noticeably at the top level and work to the next ring level down.

How is the crank (cam-shaft)? This would be key to know if bearing sizes need to be adjusted. This would help eliminate the ring ware issues.

The piston heads on top don't look too bad for the age of the engine. Was there a bunch of buildup on them prior to the video?

Glad you have a nice well laid out work area. It's ideal as you work towards re-assembly. I like it!

BTW, there are a few tricks getting off the old gummed up head gasket. 1. soak the surface suspended in a tray of mineral oil over night. Just less than 1/4-inch.

And this from CRC.

 

[winston1]

Possibility someone has used starting fluid in the past.

 

[ponytug]

Great videos.

I agree with @bmaverick that the head looks good.

Beats me how you can "ovalize" (#2) a piston on a diagonal like that. Hands down, that is the strangest wear pattern I have ever seen. Is that connecting rod flat? i.e. not twisted?

Is it possible that, in addition to the chunks of metal in the oil pan, that the oil hadn't been changed for awhile? Sludge? I just wonder about the difference in the wear for the two outer bearings and the the center, which may be just added friction from the out of round piston.

This seems like a project, but a rewarding one.

All the best,

Peter

 

[tc197]

Thanks for the comments guys. No build up on the pistons prior to the video, that's how they came out. The connecting rods all appear flat and show no signs of twisting. The oil definitely sat for awhile and hadn't been changed in years, but the tractor also hadn't been touched in years. When I got the tractor one of the first things I did was change the oil and filter but I didn't see metal like this or any chunks come out, I also didn't pull the pan to look though. Below is another video after I pulled the flywheel off to get it ready to go on a stand - I think I found a pretty big issue as you'll see at the end.

 

[California]

Ow!!!

I'll bet that thing clanked when it ran. I can't imagine not shutting down long before things got that bad.

Could that explain the chipped piston skirt?

 

[tc197]

I bet it explains why I was leaking oil from the rear main area