2013 m8 engine failure

[durangorider]

I am looking a purchasing a 2013 m8 Sno pro locally that had a engine failure. They are not sure exactly what happened but one of the pistons is fried. And he said there is scoring on the jug wall. Other piston looks fine. Should I be worried about rod or crank damage or would a top end rebuild be good? Sled has 1400 miles on it. Here are some pics. Also what would a fair price be

 

[Hardass]

With parts of the piston missing i would be worried that something went into the bottom. However the head does not look pitted by your pictures.

 

[Coldfinger]

Personally, I'd be concerned about crank damage since pieces of the piston are missing. Not versed in what to look for to determine that, beyond a visual inspection.

At a minimum, I'd say one new piston and probably jug (can't see the jug condition in the pic).

Might want to replace the other piston while you are in there. The other jug is probably ok.

Not sure about price. Look at comparables, then deduct from there for pistons/jug, labor, the unknown.

 

[jim]

Looks like lines/scoring on the crank down there. Missing pieces of piston. Major seize (the piston looks like it was ran after it seized until it seized again and broke). Very good chance that stuff went into the bottom end.

And then you don't know what caused it...something else is broke to make it lock up in the first place...usually a very reliable motor so something else is broke to cause this in the first place.

Not to mention at 1500 miles the primary clutch is usually toast...and secondary not far behind.

I wouldn't touch it. I don't think I'd even do it for free.

 

[durangorider]

When I asked the owner what he though caused it his answe was snow ingestion. Can you get the bottom end rebuild or is it cheaper to find a whole used motor?

 

[jim]

If it was snow ingestion, the guy kept running it after the initial seize and spread metal everywhere throughout that motor. I have a hard time believing snow ingestion because it would have to be a ton of snow and the other piston certainly would have scarring. I think there is something else going on with that motor waiting to waste a bunch of new parts.

You can find used motors online for $1000 to $1500. Might be a decent way to go, but there is some risk there. You can also buy a brand new motor for $3k.

If you really want that sled, I would look at typical retail for that model and subtract $3k.

But if it were me, I'd find another sled that was better taken care of. You almost have to try to destroy these motors...takes lots of neglect. Which begs the question: What else is wrong with that sled? Lots of guys around that take great care of their sleds and you would be able to get 4k+ miles without doing anything but basic maintenance.

 

[jim]

how to delete an erroneous post?

 

[SnowJam]

That looks highly neglected. I would got with Jim finding another project.

 

[Kingkittycat]

M8 burn down

That engine is just fine! The proof is in your pictures. Here's the facts.
#1. It burned down because it was running lean and for quit some time. As to why it was running lean, I don't know, you'll have to figure that out.
#2. As for the metal missing, don't assume pieces were breaking off. When it runs lean for extended period of time, it slowly melts away. Where does it go? Right out you exchaust port. That whole area melted away is exposed to the large exchaust port twice a revolution, once going up and once going down. The incoming air/ fuel charge will blast the melted metal out the exhaust.
#3. There's no evidence any metal got into crankcase area. It would have to get past the bottom ring. For a chunck to get in there, there would have to be a deep vertical groove for it to pass between the piston and cylinder wall. All you have is smearing like most typical burn downs.
#4. Metal or piston pieces in crankcase, come from broken piston skirts. I did not see broken skirt in you pictures.
#5. The head looks pretty good. When a rod bearing goes out or pieces of the skirt break off, they get blasted up through the intake ports. Every time the piston hits TDC, it smashes the pieces against the head. Top of piston and the head will be full of dents. Again, no evidence of metal in that motor.
#6. What's it worth? I have no idea! You'll have to figure that out. I can only comment on what it would cost me for a piston kit, top end gaskets, and a new jugh.
#7. Like the other guys said, it's a excellent motor, never heard anything bad about it. That wasn't the motors fault
#8. The most important one. You have to figure out what caused this so it don't happen again. Took me 3 times in one season to figure out what was
causing mine!. Buy it, fix it, ride it. Happy sledding.

 

[jim]

All respect Kingkittycat. Metal can and does find its way into the bottom end from the top of the piston. There are dents in the head (I see 2 clearly). The piston was not melted away, it had large chunks of metal fracture off. The bottom of the piston is compromised with a large ding or missing piece. The crank lobe clearly has streaking from something. And you are kinda making my point...it took you 3 times to figure out your gremlin on your last motor...that can get very expensive and cost you riding days. Also don't forget that anytime a motor is locked up, it can cause damage to the lower end that doesn't show up for a bit. But, everyone does things differently. I just wouldn't advise a gamble on this situation. That is not a standard seize and lock-up...that piston is absolutely hammered. I've fixed and ran many seized motors...but I wouldn't touch one that looked like this.