YM336D - Started knocking loud while tilling

[Car Doc]

Domush,

I see the water staining on the sleeves but I cant tell you what it will do later with 100% certainty from here. I have re-ringed lots and lots of engines w/o even honing the cyls and had no problems with rings seating etc.

NOTE on this: I cant see this in person and the surface may be so bad I wouldn't feel comfortable with it but with that said it looks useable.

I would like to see you use a dingleball hone I understand the cost etc I think the cyls would be better for ring seating. They will get a lot of the staining out also not all if its low but take out the peaks and thats what is important. The look of the cyls at that point would tell me a lot about the likely outcome fwtw.

With that said a perfectly straight and true surface is always going to be the best isn't new always the best thats easy to say??? This is a repair and what will work is what is at stake.

I believe if the stains/corrosion are low meaning into the sleeve it will work better than if they are high intrusive on the pistons. It will run fine the oil rings may not control oil as they should (probably wont) but I assure you the compression rings will do their job.

The rod bearings need replaced if the lead surface is gone and you are seeing copper bearings only have about .0015" of actual bearing material.

The broken rings on #2 are a big concern. I mentioned why in Verns thread I have never seen a piston that ran very long that didn't wear the holy crap out of the ring grooves and the cyl so read that part of his thread and I wont need to re type it please.

Btw so far so good nice work coming along like a pro!!!

 

[Domush]

Thanks for all of the advice, fellas. It's nice to have some opinions from people who aren't writing the checks, as my brain begins losing objectivity the secodn I look at my bank balance. I know deep down in some hidden recess of my neocortex the money is well spent to have new parts rubbing against other new parts and not a galaxy of pits and valleys.

That said, I broke down and ordered up two replacement cylinder liners. The #1 liner looks pretty near perfect, so I see no nee to spend the extra on it. The other two, even after some excessive honing, have some pretty extensive pitting (more like a grand canyon on #3). I'm tired of dealing with burning oil (diesel is bad enough to inhale) and it will help resale whenever I ditch this for the brand new 80HP Kubota I already have $12.65 saved up for. haha. :laughing: Maybe when I turn 140 I'll have enough to buy one. Of course, by then it'll cost $500 million and a small child with inflation.

So, hopefully all of this expense will get me a decently running tractor which won't be a worry for a couple of years (hopefully more).

So far, we have a total of $640 plus whatever it costs to have the valve seats ground today. Quickly approaching the $800 limit I was hoping to come nowhere near

Now to find someone with an 84mm sleeve puller.. wish me luck with that one

A question on the new liners.. do I need to hone those or do they come ready to go?

 

[Car Doc]

Quoting myself check this before making the order please:

"The broken rings on #2 are a big concern. I mentioned why in Verns thread I have never seen a piston that ran very long that didn't wear the holy crap out of the ring grooves and the cyl so read that part of his thread and I wont need to re type it please."

They will come honed to size however you may have to re-do it a bit because of surface rust etc anything is possible. If so the stone type glaze breaker will work on them.

I am not saying to do this but I have seen guys that know what they are doing (take that with salt) mig weld chunks of metal in liners to have something to pound against and pound them out from the bottom up this is where another special tool and special procedures will be required to do it properly and is definitely what needs be done if you intend on replacing them.

NOTE: I want to point another thing out to take into consideration and that is whether the BLOCK even can be reused again once the liners are out. Meaning if they ran that thing on straight or weak water solution the o-ring bores and so forth may need further special machining procedures???!!! (see my next comment)

Another set of eyes would be a good thing on this decision it is getting into technical territory the average guy isn't supposed to know about and makes posting pics difficult to make educated decisions.

The Sunnen square hones that are used to hone engine blocks and sleeves will clean up those cylinders and straighten them they do however take a lot of material out and you are at the .020" limit and that in itself a concern as far as noisy pistons go later flip a coin.

Like I say I have done a lot of overhauls and very few had perfect parts you would be surprised what will work as long as there are new rings and the valves all seat well, once an engine can tie every bale it will run a long time just using a bit of oil or having a little piston slap....and that can be helped by knurling the piston skirts, I have a knurling machine still its ancient but thats how we used to have to build engines I use it occasionally.

 

[Domush]

I'm headed to the garage to check the #2 piston out now. I even have some brand new feeler gauges to check with (my 40 year old set has officially been retired.. in other words.. I got tired of reading the number off the few feelers I have never used and counting backwards from there)

 

[Domush]

Okay, just checked the #2 piston (all of them really) and none of them have any rounding off at all. The edges are all nice and sharp. The oil seal and the bottom two rings on all pistons fit nice and snug, but I notice the top ring on all three is loose. Is this on purpose or is this some odd wear? I don't really see how the groove could wear like this without rounding over the edges, so I'm going to guess this is normal. Just speculating, though.

It should be noted, the broken oil ring on #2 was, quite literally, a 'lucky break', as the oil seal has a top and bottom section and only the bottom section broke (in two places), which means the top section held it together and maintained its shape. I don't even see where the broken bits made any wear at all :confused2:. This makes me wonder if the ring had just broken when the knocking started, as I can't see this staying wear-free over even a few hours of use. Again, just speculating.

As for the feeler gauge test.. the lower 3 rings (besides making a circus :laughing, fit so snug I don't think I could even fit a feeler in there with them. They spin semi-freely, but they are certainly perfectly sized for those grooves.

 

[Car Doc]

Take one of the rings that fit snug and put it in the top groove see what that measures. The top ring takes all the abuse of combustion and it will wear as well as the piston groove.

They need to be smooth along the bottom of the groove to seal and no torsional stress also thats the spec I gave.

I am going off memory on this but I think .007-.010" is max side clearance. Not saying it still wouldn't work for how we use these tractors though.

 

[284 International]

On another forum, a poster made a fairly low-buck sleeve puller out of a turned down circle of plate, some all-thread, a piece of rectangular stock, and a couple nuts. You may be able to rig or make something that would work without too much trouble.

 

[DABSGT]

[B]The issue comes in.. is replacing the liner easy enough for me to do myself? I'll need to track down a liner-puller if that is the case. I'm on the fence.. a liner costs $150, which is 1/2 the cost of the entire job right now. $470 for a rebuild still isn't awful, but that does add quite a bit of sting to the cost. We're talking about a tractor which still doesn't have a 1st and 2nd gear, so resale down the road will still be abysmal[/B]

Years ago I picked up an old JD 410 just about got her home smoked and had no power (I got her cheap). Not knowing much about motor work I like you did a front yard over hall. I would suggest replacing all the sleaves if you can and with the new rings that tractor will run a good long time. You may even decide after all of your work to keep her. But if replacing all is out of the question better do #2.

Nice job, a labor of love for sure. Have me thinking about kidnapping my uncles old AC. B and doing a rebuild.

 

[Domush]

Take one of the rings that fit snug and put it in the top groove see what that measures.

Okay, the final measurements are as follows:

#1
groove 1: 2.75mm
groove 2: 2.5mm

#2
groove 1: 2.86mm
groove 2: 2.52mm

#3
groove 1: 2.75mm
groove 2: 2.52mm

The manual says .012" is the max ring groove gap for groove #1 (and .010" for the other grooves) and here are the results of each piston:

#1
groove #1: .012"

#2
groove #1: .014"
groove #3: .006"

#3
groove #1: .012"

I used ring #3 to measure the gap on groove #1 on piston #2, just in case the original ring was overly worn. So, as you can see, assuming the ring is not worn at all, I am .002" over the max spec.. is it safe to assume the new top ring will be .002" wider (hopefully more) than the used ring #3?

no torsional stress also

I don't know what that means. How do I check for that?

The question remains for me.. if the #2 cylinder is so pitted and had such crap compression.. why on earth would it have the most worn top ring? I would think, if compression was the main factor of top ring wear, it would be shiny new and #1 would be the most worn. This tractor is a riddle wrapped in an enigma. :confused2: Does the pitting (and the oil it traps in there) make the rings have more resistance? If so, that would explain the excess wear. Sort of like driving a car through a shallow puddle vs a deep one. More oil to displace == more resistance. Again, in theory.

 

[Car Doc]

Well it is somewhat a mystery I give it that but what I see is it sat out in the open and took on water quite a few times and somewhere along the way someone freed it up and got it running again but thats my theory.


I cant/wont read mm's so if possible can you post specs in inch fractional terms thanks.

The end gap and ring side gap are 2 different and separate specs the one I am concerned with is the side gap between the ring and the piston. Its measured with a feeler gage between a ring in the groove and the piston.

The end gap is what it is- we cant change that on a standard dimension set of rings so unless they are to big to even fit in the cyl we wont even worry about that you can check one but beyond that its a moot point.

If you are .002" out of spec it will work we have to look at the big pictuer there are thousands of these engines running out there this one was up until the exhaust valves went and so on. A little extra clearance in a ring wasn't the cause of the engine fail.

We used to be able to buy ring shims and we cut the groove in the piston and added these shims to tighten up the rings. If they are available in 84mm etc I dont know but then again we are talking another machine shop procedure...with the throw away nature of engines these days finding an old school machine shop may be tough.

That and what does a new piston cost that makes more sense to me than new sleeves but then again I cant feel the cyls either but either way 3 new pistons will fix all these issues.

Your compression and leak down figures are something to fall back on in asking yourself these questions and is the EXACT reason I ALWAYS say get that first we need those facts before someone tears into any engine. :thumbsup:

quoted from you-

Does the pitting (and the oil it traps in there) make the rings have more resistance? If so, that would explain the excess wear. Sort of like driving a car through a shallow puddle vs a deep one. More oil to displace == more resistance. Again, in theory.

Resistance is futile (pun) to the engine all that makes no difference whatsoever it is more along the line of how well the cylinder stays sealed above the rings as the combustion pushes the piston down the stroke. The further down the pitting etc is the less pressure there is and the less will blow by into the crankcase and the oil rings can continue scraping and returning oil back to the crankcase. hth

edit: me "no torsional stress also"

I don't know what that means. How do I check for that?

You are by doing the feeler gage measurements. The side clearance will cause the twist (torsional stress under combustion force) if there is too much the ring face doesn't have constant effective contact with the bore and the wear is accelerated by the clearance the more slapping around they do the more they wear, that and they dont seal real well either. fwtw.

edit #320 haha: The question remains for me.. if the #2 cylinder is so pitted and had such crap compression.. why on earth would it have the most worn top ring? I would think, if compression was the main factor of top ring wear, it would be shiny new and #1 would be the most worn.

Ok pressure is the answer! The pitting is water simple as that. Uneven cylinder pressure is one of an engines enemy's beside contaminants think of everything in the rest having equal pressures which one was worn? #2 and we know for a fact it had no compression and no fuel so the pressures were unequal in comparison to the rest does that make sense yet?

Another way to see the why the wear is that on an intake stroke there is a negative pressure in the cylinder thereby that pulls oil onto the rings and cools and lubes them and on a compression stroke the compression rings seal and the lower compression rings scrape oil and seal the cylinder at the same time and help the oil rings do their job. The differential of pressures complements all the parts and w/o that they just flop around for lack of a cool way of saying it.