CK35 HST shattered piston at 400 hours

[deezler]

Whoever said something about the neighbor possibly using ether/starter-spray... that's also a very viable theory. Dramatically increased cylinder pressure places a lot more side-load on piston skirts. Due to the high compression ratios of diesel engines, this is a big no-no.

 

[sd455dan]

I have put 3 piece rings in tons of bikes. There is no way that serrated expander ring is supposed to ride against the aluminum along the bottom of the groove. No way. That's just common sense, i.e. no mechanical engineering degree required.

As another posted- that engine is equipped with 2 piece oil rings... When the metal in the pan is dissected the missing 2nd part ( the actual oil ring) will likely be found-in pieces

I did read the entire thread... i hope the picture helps explain the difference in oil rings used in the Kioti

 

[Fawken]

Where are the pieces of the 2-piece ring? Look closely at picture #1. The piston broke exactly in the center of the groove. The outer part of a two-piece ring would be in the pan. It could not still be riding on the piston because there is no bottom lip in the ring groove to hold it in place. And if it is somehow still in place, then how did the expander fall out? Oh, it could fall out if the outer ring broke, but where are the pieces of it?

 

[deezler]

As sd455dan notes, the oil ring body could be obliterated and smashed into tiny bits. I've seen this happen, but usually you can find at least part of it in the pan. Look closer at the picture though - see how part of the piston did not break off? That bit under the bottom pinbore is still fully intact. There could be enough ring groove left there to retain the ring. Those 2-pc expanders are pretty squirelly - it could escape and fall into the pan pretty easily.

We're all armchair quarterbacks without some better pics and info though.

 

[sd455dan]

Where are the pieces of the 2-piece ring? Look closely at picture #1. The piston broke exactly in the center of the groove. The outer part of a two-piece ring would be in the pan. It could not still be riding on the piston because there is no bottom lip in the ring groove to hold it in place. And if it is somehow still in place, then how did the expander fall out? Oh, it could fall out if the outer ring broke, but where are the pieces of it?

My guess is that if a person were to take a magnet and run it thru the oil pan- it would become obvious.
The piston is aluminum(whether forged, or cast) - so what is picked up by the magnet other than the expander is the oil ring.

This should help figure out this puzzle a little bit.

 

[Fawken]

As sd455dan notes, the oil ring body could be obliterated and smashed into tiny bits. I've seen this happen, but usually you can find at least part of it in the pan. Look closer at the picture though - see how part of the piston did not break off? That bit under the bottom pinbore is still fully intact. There could be enough ring groove left there to retain the ring. Those 2-pc expanders are pretty squirelly - it could escape and fall into the pan pretty easily.

We're all armchair quarterbacks without some better pics and info though.

Hard to tell if that little part of the skirt is still intact or if is just stuck on a lip in the block. Regardless, zooming in on the upper part of that same picture you can see a compression ring so, no it is not still being held in place. I would really like to examine this engine up close. IF (and that's a big "if") I did find the pieces of the rest of the oil ring in the pan, then what does that say for the quality of Kioti pistons? The other possibility I see is the end of the bore seems awful close to the bottom ring groove.

 

[CenTex Chris]

please confirm the following:
1) Did more than one cylinder/piston fail?
2) Did you neighbor notice the tractor rev too high at any point during operation?
3) Is there any history of funky engine operation or high oil consumption before this event?

1. No, as far as I know. The Kioti mechanic who discovered it told me just that it was the #2 piston. In fact, when I crawled underneath to look up into the crankcase, he told me to look at the other two for comparison, to see what they normally look like. I took photos of the other two as well, but not as many and I'm not sure that they're very clear. It's pretty close quarters up in there and I was trying not to get motor oil on my camera. A quick note about these pics... at first, #1 and #3 pistons were down and #2 was up, making it difficult to get a good photo. I moved out of the way and he bumped the ignition for me which brought #2 down so I could see it better. If you notice different positions for the broken piston, that's the reason why.

2. Unknown. I'll have to ask him. I was afraid that maybe he over-revved it but I thought the governor was supposed to prevent that. We live in a very flat area (east of IH-35, not the Hill Country) and our road on which he was working is very flat. No grade to speak of at all.

3. Nope, not at all. It's always held oil very well and the first thing I did when I discovered the knock was to check the oil level and quality. It was full and very clean. Although it is due for an oil change (but it's not overdue).

More pics for you. I have to be careful here because the last thing I want to do is get on Kioti's bad side by posting these. The latest word today is that they'll have a decision for me next week. I wouldn't be surprised if they're watching this thread. At the same time, I have no problem sharing these pics because this is something that happened which might be of interest to other CK owners. However if I get a message saying it would be better for me not to show these photos then I'll have to take that under consideration.

The bits and pieces in these pics are only what I could recover... there was a lot of very fine debris, pulverized aluminum and tiny little aluminum nits, etc. that did not survive for evidence. The pan was emptied and re-installed. Obviously I have kept all of the larger chunks. Does there seem to be enough material here to account for more than one piston skirt? Not to me, but what do I know. You see a snap ring, a tiny shard of expander, and up in one corner there are two small pieces of oil ring. That's all I could fish out of the pan.

The two longer lengths of expander form a circle about three inches in diameter. Originally there was more to it than that, but does three inches sound about right for a piston diameter? The most telling component is the piston itself and I won't be seeing it again until it's in somebody's shop. I'd definitely like to know the condition of the other two pistons.

I'll tell you what I would like to have happen. I'd like to be able to brag about Kioti. I'd like to sing their praises throughout Kioti-land. I sure hope they give me the opportunity to do that.

 

[CenTex Chris]

And to me it looks like part of the ring is still in there.

 

[Industrial Toys]

I had a crank break in my twelve year old Kawi Mule. Called Kawi and they basically said too bad, so sad, it's an old machine. I escalated it and they agreed to do the exact same thing. Pay for parts, I pay for labout AND I have to take it to a dealer. Twelve hundred or so dollars later, it's fixed. Better then nothing, but I had to fight (a little) for that.

 

[CenTex Chris]

Whoever said something about the neighbor possibly using ether/starter-spray... that's also a very viable theory.

I'll have to ask my him but I seriously doubt this. It had been starting just fine.

In fact, it still starts... and runs... barely... but I'm not about to try it again until it's time to lift the loader arms and ease it off the trailer.