OUCH! what happened and why? 2 stroke Piston Failures

hey guys welcome back so today's video we're going to be showing you piston failures basically what happened to them what causes it and how to fix it so the main thing when your engine fails you want to know what happened and what caused it so you can make sure it doesn't happen again in this video we're going to show you a whole bunch of different things that cause these Pistons to fail and what to fix them follow along with us guys thanks for watching [Music] what's up guys welcome back first I want to thank everybody that went to ericksonmmp.com and bought some of our merch right now we're doing the 10K giveaway if you guys buy or have any of our merch posted on Instagram post a picture tagging us in your merch doing something fun with a family jet skiing whatever it is shenanigans and we're going to be picking a winner from that want to thank everybody it's greatly appreciated so today's video we're going to be talking about piston failures what causes them and what to look for so this is a really important step when you're rebuilding an engine to make sure it doesn't happen again I would love to say that you know everything is fixed the first time but unfortunately it doesn't always work that way and a lot of times people just think it's one thing don't look at it or get bad advice on what caused it and it happens again which is terrible so we're going to be showing you a whole bunch of Pistons that I've collected you know over the past few months so that I can show you what happened to them what caused it and what the solution is so there's several things that really lead to engine failure so there's detonation which this Rose mainly detonation some of these Pistons have multiple failure causes which is the other tricky thing diagnosing this because you know you can end up with detonation because the lower rod bearing starts to go the Piston comes up higher which increases the compression and wipes everything out you look at you go oh you know it's detonation whatever you don't notice the rod bearings failing you put it back together it happens again same thing with lean conditions you know you think whatever oh you need to rebuild your carbs but it's really you know the seals that are bad or you know the case is leaking something else you put it back together and it fails so you really want to pay attention to this stuff to make sure it doesn't happen again so with that Nation it mainly looks like sandblasting so when you look you can see all the little pits on the top of this piston this was too much compression for the octane used um so you have to be careful with that but that's one of the signs so you can see it on this piston you can also see it on this one it's mainly it looks like sandblasting which is the best way to describe it now the tricky thing is when these start to get hot you super heat the top ring the top ring can break and then it can actually put little hard pieces of metal in the top where it looks like a crank failure so here is another eaten detonation piston this one was just the start of it and this is detonation that's really bad but it was caused from a rod failure so basically the rod bearing failed which allowed the Piston to come up higher which caused the compression to go past what the fuel could accommodate and it decided to kick its way out so that's really The Telltale sign of detonation so there's detonation and then there's pre-ignition which this can happen from lean as well where the mixture gets so combustible that it starts to explode now lean you're normally melting metal so with detonation my understanding is when it detonates you damage the air barrier and when the air barrier is damaged from that shock wave that's what causes this pitting with lean the mixture gets so hot that you start melting stuff so you super heat the top of the Piston it's very common to melt off the section around the exhaust where you can see here you know here are the locating pins in the back so it melted this whole upper edge off which is what took out this piston same thing here where it's superheated it it basically turned the spark plug into a glow plug superheated that and started melting its way I believe this one's melted all the way through yep same with this one you can see the edge of the Pistons melted away there's some detonation on this as well and burning a hole now if you look on this one it got so hot melted it away and broke the ring which happens and then you can see the imprints in the ring on top which is where you have to look you know a lot of people get confused between detonation which is this and debris damage which is this two totally different things um so lean you can also check over here this one was extremely lean he overheated everything and locked it up before it melted so on and so forth here so now we're going through debris damage so this is in printing in the top of the Piston so like you can see this one you can actually see the piece of metal there um so something on this one went past the flame arrestor and nicked everything and beat it up pretty badly you know this we found taking it apart but it's still a totally fine engine um oh no this one we did it sorry I forgot which one it was so you can see that piece of debris went past everything it got caught in a port and beat it all up but that's debris damage here's more where you can see it's actual imprints in the top of the piston and you'll see it on the head as well this was most likely a crank failure I don't remember what it is but you can see large chunks and detonation now the tricky thing with debris damage is the pieces of metal that bounce around actually turn into like glow plugs and cause detonation so you can end up getting both where I was telling you know there could be multiple failure modes in it which is where this one is showing you know this was Heavy debris damage from a crank failure most likely that also detonated the whole top of it which is why it looks sandblasted over here where these are so this one was loose this one was loose this was a crank failure and this was a defective piston now having defective Pistons is extremely rare I've only seen a couple in about 25 years this was one of them where it looks like when the Piston had these oiling holes drilled it caused a crack in it because it split the piston in half this had less than two hours on it um the company that made the Piston completely warrantied everything for it we redid all the work for the customer and it was replaced but it is extremely rare to see this happen so it's better off not to blame somebody but to kind of look at all other options before you go that way so this one we got it back this was an engine we built a couple years ago it had like two hours the Piston came apart it was all sent back to us we repaired it all we fixed it all and we sent it back out completely re-fit completely repaired sorry I can't talk today so here is a rod failure which damaged the skirt normally when you're damaging skirts like this it's because there's too much Rock so a piston is not designed to rock like this in the bore so when you measure a piston the top of the Piston is smaller than the bottom because the top gets way hotter than the bottom does So in theory when these things are at operating temperature although their Barrel they're tapered now they end up straightening out so what ends up happening is when the Piston's too loose in the bore it rocks like this going up and down and as it rocks it will start bending the skirts in and then eventually the skirts will break and then it will go like this and Destroy Everything which that is what happened with this one a shop set this up this was like a brand new actually I know exactly which one this is so this was from a major engine rebuilding company um I'll just say in Florida that has three letters that this thing was sent to the customer with thirteen thousands clearance this engine had like an hour and a half on it and wiped everything out we repaired it and it has been running since but that is what too much clearance looks like when you start breaking skirts it's either the rod failed or there was too much Rock in the Piston there was way too much clearance same thing with this this was a four stroke that came apart so but that kind of shows you that now other things that cause damage but don't necessarily destroy the engine if you see streaking like this so this is from water ingestion it's really really common on freestyle engines let me see I don't know this one as well so this you know in all honesty this will not really kill performance if you get a lot of it you'll actually hurt the sleeve but the main thing is you want to figure out why you're ingesting so much water and try to stop it before it wrecks everything so when you see streaking like that it is from water ingestion or it could also be you lost a head gasket and that's what's causing it so that's water ingestion to look at now this piston this was another rare one this engine had sat for a very long time obviously it wasn't fogged correctly and when they fired it up it had zero compression it brought it to me for me to check it out if you notice the piston rings are completely locked in so the ring Groove you can't open them up so this engine is one of the rare ones where you you lose a ton of compression and the engine's actually not blown up surprisingly if I recall all we did was hone this one and put new pistons in it and it was good to go we replaced it because there was rust on the pin board and at that point it's time to replace these puppies so that shows you you know if the Rings lock up it's fairly rare but it does happen this one was I believe this was a cold Seas on a fresh engine it would be the same as basically being too tight so that is normally where you'll see a multiple Point seizure on it where you know unfortunately some of these things can look similar so too tight overheating or cold seizing where cold seizing what I'm talking about is if you're running in really cold water the engine is hot and then you go idle in really cold water the cylinder will actually shrink from the cold temperature and all of a sudden you'll take up all your clearance and you'll lock them up so this was like a January ride somebody was doing and cold sees that setup luckily we were able to pour acid put new pistons in it and it was good to go uh um these were damaged from getting water splashback on the exhaust so this engine he was running a lay down pipe with no water box and every time he would do a trick it would splash the exhaust port we ended up it did a lot of damage because water will take the oil away which is what locked all this up and wrecked it we ended up putting one of our water boxes in it and it has been running for years at this point running great so and you can see you know people talk about piston watch which we're going to do a whole video on tuning as well showing piston wash and what you're looking for the tricky thing is everybody goes right to piston wash that that's what you want to look at and one it doesn't react quickly and depending on the Dome of the Piston it changes the shape that you want so on a dome piston you normally want about a fingernail's worth like that that's kind of what you want to see on the top of the Piston but on a flat top piston because you know the fuel is actually washing the Piston as it's going over on a flat top piston it's less because although the fuel is coming in on an angle coming out of the port the Piston's flat so less of the fuel contacts the top of the Piston which means the Piston wash ends up being less this was I think this piston was just in for a general rebuild this was a race motor we did but I stepped it this is going to be in the Piston wash video I just wanted to kind of show you guys some of it because all of this goes together so all of this knowledge so piston wash reading spark plugs checking compression you know they're all tuning aids to make sure that you're in a good spot every setup is different some engines run great one way some engines run great a different way so there's nothing really set in stone in these I've seen engines with 180 pounds compression detonate I've seen engines with 200 pounds compression not detonate so riding style comes into play setup cooling carburetion everything has something to do with this but this kind of gives you a good idea what to look at at your pistons and what caused the failure you know in general if it looks like it's sandblasted on top odds are detonation caused it if you have melting on your piston odds are it was lean if you have debris damage something went through your engine now whether something fell in through the flame arrestor or your cranks coming apart or a screw came out of a reed valve something like that if you're breaking skirts on the piston odds are it's too much clearance if you have streaking on your piston in a watercraft odds are you're getting water ingestion with whatever you're doing or you have a leaking head gasket so but I hope this video worked out for you guys I hope you liked it if you have any questions comment down below please like share and subscribe have a great day guys thanks for watching

Channel: Erickson Machine & Performance

Views: 16,535

Keywords: piston failures, seized, over heated, oil, detonation, lean, 2 stroke, two stroke, engine failure, fail, failure, yamaha, 701, 62t, 61x, kawasaki, 650, 750, 800, 760, pwc, freestyle, port, brap, brapp, brappp, jetski, jet, ski, ported, cylinder, head, burrs, machining, engine, builder

Id: ZfRxBvjNShY

Length: 16min 11sec (971 seconds)

Published: Mon Aug 07 2023