YM336D - Started knocking loud while tilling

[284 International]

All of my tractors will pump fuel whether they are connected to an injector or not. If the number 2 line isn't pulsing fuel, but the others are, at least some of your roughness is accounted for. The pump needs some servicing, for sure. I have read that a little "percussive maintenance" with judicious hammer taps can loosen stuck plungers, but I don't know anything about it personally.

I DO know about doing the things one isn't supposed to do when rebuilding an engine to keep it on the cheap side. . If the seats aren't hammered beyond repair, one can hand lap them so they seat cleanly again. The glass or granite discard suggestions for flat tables are superb, and what I have done. I have used Harbor Freight's cheap combination square as an improvised machinist square for checking the trueness of flywheels and engine blocks. It's not necessary to buy that one particularly, of course, I just happen to have one in my tool bag, and it has a variety of angles and shapes and sizes that work well on small engines with their sometimes unusual head stud arrangements or packaging in the frame. Machinist squares are better, but I use what I have at the time. With a set of feeler gauges, one can very easily determine if something will work or not. For me it's akin to a go/no-go headspacing gauge for a firearm. It tells you if it will worker not, but isn't best practice alone, either.

You'll hear this a lot, but make SURE to mark your rods and their bearing caps as to orientation and number. Front to front, etc. Since I'm prone to leave things for a long time, I usually do different colors of fingernail polish in slightly different spots, so colors and alignment have to match, on the crank or block and the bearing caps alike.

From my perspective, put new rings in it. The thing has worn the cross-hatching off, so the cylinder wall and the ring are smaller than they should be. The rings will have lost tension too; they can't seal as tightly as they ought no
matter what. It will start easier, too.

I'm pulling for you, I really hope you can get this beast back together. I'm envious of your industriousness and dedication getting it looking so nice. Hopefully you can get it running that way soon, too!

 

[clemsonfor]

If you want to test the injector and swap lines around and stuff you can put the head back on with the old gasket at this point just for a test, but after finding this damage/wear on the cyl i think i would address that first, then maybe reassemble with the old gasket for an injector pump/line test if you decide not to take it (the pump) immediatly to a repair shop. Once you determine the problem or take it to a pro remove the head and then final install your new head gasket.

Kabotain you use the little button on each post looks like this " then you click each post you want, then on the last one actually click the "quote" button; and delete what you want to get it shortened like he did.

 

[Car Doc]

Domush,

Please take the lines off the pump and spin it check the flow w/o lines!

I dont know if you saw that in my last post or not it may save a lot of un-necessary work and a real headache later a pinched line wont flow.

 

[Domush]

Okay, I removed the injector lines altogether and cranked it over a bit (not much as I have already drained the oil) and #2 is spitting out just as much fuel as the other two, so I think it may have been a case of an empty line and not enough cranking to fill it up. Though I'm puzzled why it would be empty at all, as the other two were not. I'll come back to that later with a pressure test of the #2 line.

I'll be pulling the pistons today. I'm curious what the rings will look like.

Hopefully I can find a place to loan a ball hone, as I'd hate to pay $50 for a one-off use.

Now, I'm really hoping to not have to split the tractor and remove the engine in order to complete this rebuild. This means, of course, honing becomes an issue, as I don't want to risk not being able to clean out all of the debris. What I'm considering is pulling out the cylinder liners and honing them while they are out.

Does this sound reasonable? I know they are "wet" liners, so they are thick walled, which means they shouldn't warp while getting honed. The service manual mentions these can be removed without pulling the engine, so that seems like a promising approach to me. I simply don't trust my ability to effectively remove all of the particles honing will loosen up. If I'm just being paranoid, let me know, as if I can skip this step it'll make me life even easier.

Any advice as to how to go about the honing process? Pull the liner? Leave them in and clean well with xxx fluid? What about the crankshaft? Will that be in jeopardy with all of the honing debris flying around?

Also, any thoughts as to how to break the injectors loose from their homes? I can't seem to get them to budge after removing the hold down nuts.

Luckily it is a beautiful day here in KY country. I'm even keeping the windiws closed in my house as to keep the house cool! Mother nature was waiting for March to come for warm temps, I guess. A full winter without having to refill my propane tank! Yay! (pretty much the only reason I can afford this rebuild, haha)

 

[Car Doc]

The pump working on 2 is what I was hoping to hear that is good there could be a tiny piece of rust or dirt clogging the line or a pinch not visable. So lets hope so because at that point I would leave the pump alone and do the re-ring and see how it runs after that.

Oh and you arn't going to hurt anything by spinning the engine over checking the pump there is plenty of oil on everything dont spend all day at it but for our purposes no problem.

The liners just leave them alone it takes a special tool etc they are stuck in real good. The hone will just be scratching the surface with minimum pressure what I do is wrap masking tape around the rod journals and turn them down. After getting all the surfaces scratched real good spray them down with brake clean a then use oily rags wipe down until no more sand dust gets on the rag.

Spray down the hone while honing with either spray oil or brake clean. I use it with brake clean so it is more a dry process what you are wanting is the entire surface look like an x cross hatch. and fyi these dingleball hones work real fast you wont be spending much time on any of them fwtw.. The zone loans them I am pretty sure check and see?

www.flexhoneblog.com/2009/11/dingleberry-hone-dingle-ball-hone-or.html just fyi a quick search...

another www.enginehones.com/hones.html This is the one I would buy- www.enginehones.com/312240sc.html

How to- www.enginehones.com/technical.html

And you achieve that by fairly quickly moving the hone up and down the cyl dont pull the hone out w/o it being moving it will make vertical scratches that we dont want in there.

Obviously as has been mentioned keep everything orientated you know that just saying and be extra careful you dont nick the crank pushing the pistons out I use a wood or plastic hammer handle end and if you do make a mark a small file and sand paper will fix it fwtw.

The injectors will undoubtedly be full of dirt and rust spray oil and air is your friend there and patience. I suppose they could be knocked out from the bottom using the pre-chambers as long as you were real careful not to dent them maybe use a socket that fit the outside edge?

If I think of anything else I will post back good luck glad the weather is cooperating.

edit: Don't worry about all the debris if you are fairly diligent with the the air and oily rags in the cyls and so forth the oil filter will get anything out that would do any damage. That and anything small enough to go thru the screen will not stop the oil pump and will be caught by the filter so get all you can out and dont give it a second thought beyond that. One exception is wire brushes that will not be an issue if you dont use one.

And I would cut the filter apart soon so as to know how much metal is in there before calling the mains and so forth good etc. I believe the knock was no compression/fuel on #2 at this point but we need all the facts we can get now..

 

[Domush]

Alrighty then!

I now have a hone, a valve spring compressor, a ring groove cleaner, plastigauge and valve lapping compound. I'm wavering on whether to front the money for a ball hone, as i couldn't find anyone with one to borrow. Is a ball hone needed or will the 3 legged one do?

I removed the exhaust valves (the small ones) and boy are they worn! The intake valves look fine, really nice even. All valve stems are within spec, as are the guides.

The exhaust valve seats will likely need grinding as they are pretty rounded. The intake seats look great.

I did some sanding on the head but still have a bit to go. There are a few areas which are pretty caked on, and my arm was beginning to feel the burn.

I haven't pulled the pistons yet, as I was feeling lazy and the head was on the bench at bench height.

I priced out everything I think I'll need for the rebuild, here is the breakdown:

WPG-2000 GASKET WATER PUMP TO BACK PLATE $1.58
RS-252 RING SET (3) $142.26
HG-250 HEAD GASKET $65.71
EV-4600 EXHAUST VALVE (3) $41.40
RB-45 ROD BEARING STANDARD (3) $46.74
Total: $297.69

I decided to suck it up and get the bearings. $300 is certainly doable for a rebuild. I still have the pistons and connecting rods to check before I place the order.

On to the eye candy (or eye sores, depending..):

#1

#2 - Notice the dull appearance inside the exhaust valve. The other two are shiny. I'm not sure what this means. Any thoughts?

#3

The intake seats are nice and angular

The exhaust seats.. not so much, but not awful either. They are kind of pitted (all 3), though.

The intake valves all look nice and clean like this one.

The exhaust valves on the other hand.. notice the razor sharp edges. They are all still within spec for face width, but I don't see that being true much longer.

The head with the gasket off

After light hand sanding with a rubber block, a couple pieces of 220 grit wet/dry, some Marvel Mystery oil and a pair of tired arms. I'm a web developer.. this stuff is considered effort to me

Tomorrow the pistons come out and the honing begins.

 

[Smoody]

its coming along, thanks for documenting this all, may come in real handy someday..

Do you plan to replace the sleeves or just hone them, just curious if you hone them would you not have to get larger pistons depending on how much you hone out? am I understanding that process correctly?

 

[clemsonfor]

its coming along, thanks for documenting this all, may come in real handy someday..

Do you plan to replace the sleeves or just hone them, just curious if you hone them would you not have to get larger pistons depending on how much you hone out? am I understanding that process correctly?

Nah, your honing, not fileing or boreing. IF you just do it till its shiny and crass hatched like Doc says. Your only taking the few minor verticle scuffs if any may exist, the rust at tops and the minor pitting out, creating a fresh surface for the new rings to seat against. The new rings will take up any small amout of metal that was removed. Remember this is not a total rebuild or how you would expect one to be done at a shop. The honeing and reringing is pretty common though for back yard guys and cheap rebuilds.

That is unless he goes crazy honeing on each cyl for 30 mins or something. Me personaly have not done any of it, thats not to say i wouldnt try like Domesh is doing though, engine is due anyway?

Domush, by the way great work your doing a fine job, and you sure your a web designer? Your doing good Fast work here and providing great details. I think the webdesigner helps with the pic process as thats most folks problems it seems on here. This forum is better in that i can put many large pics on here at one time another forum im on Hearth.com (wood stove forum etc) they oly take like 1meg a post and pics have to be tiny to go up, what apain resizing etc, and then they dont ever look like other guys pics???

 

[Car Doc]

Domush,

Stay away from the traditional stone type glaze breakers they don't conform to a cylinder properly once there is wear the dingleball hone will and rings will seat 100 times better.

You need the valves and you need the exhaust seats ground the intake seats look good and may well lap in I would have the valves ground also. So 3 exhaust seats and 3 valves ground at the machine shop minimum. Better have them all done and you are covered.

To air check the valves you assemble the head and spray dawn soapy water on the chambers and spray air in the ports see if the seats bubble, some is ok but a perfect seat is desirable.

btw dont go wild about getting all the dark spots out of the surfaces that is only stains you only want to get them cleared of gasket material and make them soooth and that's as far as need go.

 

[Domush]

Okay, I pulled the pistons today. All three pistons look great and are all within .01mm of new spec, so they are in prime shape. The oil seal on the #2 piston was broken in two places which certainly explains the massive oil burning. The ring ends on the #2 and #3 pistons were pretty much lined up perfectly, which certainly didn't bode well for compression or oil consumption.

#1 piston (which has the cleanest sleeve) had all rings where they are supposed to be and could probably be reinserted as is, as it looks great, but I'm going to replace the rings and hone it anyhow.

Stay away from the traditional stone type glaze breakers

Oops.. too late . I already honed all three liners, though it didn't seem to do much. I used the 220 grit blades and Mystery Oil, but the blades seemed as though they were gliding on the oil and not actually honing, so I switched to Liquid Wrench, but not much happened with that either, so finally I switched to WD40 and that seemed much better. I considered carb cleaner, but it evaporates much too fast (mostly acetone).

I would have the valves ground also. Better have them all done and you are covered.

I'm bringing it in for 3 seats.. might as well do 6. Likely won't be much of a cost difference, as it only takes them about 15 seconds per seat anyhow (according to some youtube videos I've seen).

To air check the valves you assemble the head and spray dawn soapy water on the chambers and spray air in the ports see if the seats bubble, some is ok but a perfect seat is desirable.

That makes sense. Noted.

dont go wild about getting all the dark spots out of the surfaces that is only stains

Oh, cool, then I'm already finished! I did the same to the block as well today. I noticed the sleeves protrude a hair's width out of the block which makes sanding between them difficult. Any tips on that?

Here's what I accomplished today..

The pistons are now removed, about to polish it up

The piston sleeves protrude a bit and sanding the gap between cylinders is proving impossible while keeping the sanding flat. Not sure how to work around the issue without tilting the sandpaper and risking making a trench.

#3 sleeve before honing. It looks pretty good to begin with, so honing should really help perfect this one.

#3 after honing. This one is nice and smooth, now. It looks crappy in the photo, but it is really smooth and barely off original spec.

#2, the one with the broken oil seal. It is reasonably pitted with what look like rust remnants. This one needs the most work.

#2 after honing. I can still feel roughness in there, but I don't dare hone it too much. Right now it measures 84.20mm, which is max spec. It should be noted, the service manual is useless for the pistons. I'm not sure if in later years Yanmar swapped out the 84mm pistons for 90mm or what, but all piston/liner specs are for a 90mm and mine is 84mm. I had a major "no way is this 6mm off!" moment before I figured that out.

#1 with that weird oxidation hump. Everything else is nice in there except for that hump

#1 after honing. You can see how nicely it turned out, but that hump is still there, though not as pronounced as before. Not sure what to do, here. I still have .07mm to go before it maxes out spec

The pistons all look great with no scoring. This is piston #2. You'll notice near the wrist pin the broken spot on the oil seal. The broken bits are in the background. They somehow managed to stay within the oil seal and not fall to the pan, and still managed to avoid scoring the cylinder liner.

#1 bearing. This one has the most wear. You can actually see copper. It is just enough wear to feel with my fingernail, but not my fingertip.

#2 cap looks perfect, likely because it was low on compression and didn't do anything

#3 shows a little copper as well, but not enough to feel any ridges, fingernail or no.

The connecting rods are all straight to the eye (it seems any bent rods are unmistakably obvious from the 'bent rod' threads I've seen on here).

Well, that's it for today. At least now I can place that Hoye order, now, as I know what I'll need to replace, which is exactly what I estimated in the previous post.

As always, any advice is appreciated. I'll see if I can't find a ball hone to borrow on Monday. Maybe a local diesel place or even the auto guy down the road will have one I can borrow. I hate paying $50 for one for one use. I'd rather that $50 go towards the break-in oil change.

EDIT: Oh, I also cut open the oil filter and it was clean of any metal filings. I expected it to be full of sludge but it seemed pretty okay. It was dark, but reasonable healthy and clean.
Cheers!