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Deleted member 149229
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Can’t tell from all the dust.
Damage to 372xp
- Thread starter jr27236
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jr27236
Addicted to ArboristSite
I know bad pictures he sending. I'm gonna have to wait till Tuesday but with what I have at least he is kind of locked into its condition before he decides to squeeze some 2 stroke in there lol
For some reason Husqvarna has bearing problems with those saws, never see it much on Stihl saws of that type and age. My guess is a bad bearing. I have one of those here in the shop right now.
Trent Curtis
ArboristSite Guru
Scoring comes from a couple things. Heat or mechanical failure... broken ring, bearings, carbon etc.
Can we agree that straight gassing causes the saw to run really hot (friction)? And the exhaust side of the piston is exposed to the highest temps?
So how does straight gassing not toast the exhaust side of the piston??? Every straight gassed saw I've ever seen has damaged the exhaust side. If caught early you are dealing with aluminum transfer, or in other cases a piston that tries to weld to the cylinder walls.
The lean condition you are referring to is an air leak I assume? Which simply means the saw isn't getting enough fuel/oil to lubricate properly.... again causing HEAT and the exact same symptoms.
Trent Curtis
ArboristSite Guru
additionally, it's rather suspicious that he is "selective" in the pictures that he sent your way. No pics of the cylinder walls, or exhaust side of the piston?
IF this was simply a mechanical failure it will be obvious looking at the cylinder and piston. A piston/cylinder exposed to extreme heat looks very different than a saw that catches a ring or throws a bearing while being properly lubricated.
I think it was Ms.White, in the library with the lead pipe
IF this was simply a mechanical failure it will be obvious looking at the cylinder and piston. A piston/cylinder exposed to extreme heat looks very different than a saw that catches a ring or throws a bearing while being properly lubricated.
I think it was Ms.White, in the library with the lead pipe
Big_Wood
westcoast dweller
the PTO bearing does look dry, i would even go so far as to call it crispy lol hint hint it looks like that bearing spat out it's cage and overheated really bad before it died toasting that side of the case in the process. most times a cage just lets go and wipes out the compression not allowing a major bearing overheat but if a cage comes apart and the saw passes it into the muffler it can run til it burns like that saw did. the scoring half way up is the cage bouncing around in there. the top of the piston looks good as far as color, even the ring groove looks like it has some oil on it yet.
i don't believe this saw was straight gassed and he probably wasn't lying. look how clean the intake and carb is still, doesn't even have a tank on it.
lets get walt in here to discuss this metal cage failure lol @weimedog
i don't believe this saw was straight gassed and he probably wasn't lying. look how clean the intake and carb is still, doesn't even have a tank on it.
lets get walt in here to discuss this metal cage failure lol @weimedog
RIDE-RED 350r
No wing, no prayer
In my experience, when only or mainly the exhaust side of the piston is melted and leaves transfer on the cylinder, that is cause by a lean condition, usually an air leak. Yes, the exhaust side of the piston is the hottest. I the case of a lean condition burn down, it's the extreme combustion and exhaust heat that starts to melt the exhaust side until the ring land smears and "seizes" the ring resulting in the loss of compression and the engine to stop running but not locked up tight most of the time. Most times the intake skirt is mostly unscathed or sustains little damage compared to the exhaust side...again based on what I have put my hands on. I have seen extreme cases of a lean burn down on larger two-strokes where the exhaust side of the piston crown had actually begun to erode away leaving a rough/pitted finish.
The piston showed by the op had definite scoring to the intake side of the skirt, and alot of it. Most likely from bearing debris flying around in the bottom end.
Now talking about straight gassed, we all know that piston skirts expand when they come up to temp, but still not to zero or near zero clearance with the bore. You can easily start your saw that is still hot two seconds after shutting it down right? Yes, mix oil does play a role in piston/bore lube, but I see the ring/s amd bore as a little more durable to no oil supply than the bottom end bearings. There is an inherent slippery relationship between the rings and plated bore. But based on what I have seen, the bottom end is usually the first place failure occurs in the absence of mix oil. Bearings spinning at 10K or more rpm will exhaust their oil in pretty short order when the oil supply is cut off, especially the caged needle bearing that is the lower rod bearing in this case. It's the weakest link in the system. It takes the up and down stress of the piston stroke as well as rotational load. That bearing works hard. Now add the factor of heat already present in the bottom end of a saw that is fully up to temp and running hard.
I still say: Straight gassed/extremely poor fuel quality, lower rod bearing failure.
Lets see what the OP comes back with.
Big_Wood
westcoast dweller
in his second pic of his first post you can still see the gold color of a healthy big end cage. that color would be long gone if it let go.
RIDE-RED 350r
No wing, no prayer
Could be.
That same pic you can almost see the piston crown in the squish band area looks peckered up from debris. Definitely a bottom end failure of some sort.
I'm waiting to see what the prognosis is for sure.
That same pic you can almost see the piston crown in the squish band area looks peckered up from debris. Definitely a bottom end failure of some sort.
I'm waiting to see what the prognosis is for sure.
Big_Wood
westcoast dweller
straight gassing also would have left the top of the piston a grey color just like the bottom end. second pic, post 20 looks like the balls have piled up in that bearing. always neat to see a saw that died for a good reason lol
Adirondackstihl
Flyz, Fuel & Fotos
I’ve yet to pull apart a saw that was ran @ 50:1 and have it appear “wet”.
To me....by photo inspection only, knowing the model, it ate a bearing. Which one? I’ll leave that up to forensics. Most likely one of the mains. A piece of said bearing wedged between the cylinder wall and skirt and perhaps some more made it up through the transfer tunnels.
Straight gassing normally scores the entire circumference of the bore, not just the intake side.
I’m guessing he was given her the ole piss rev test when sh!t went south.
The only other time I’ve ever seen a piston look similar to that is when I cold seized my 066 in -30 temps while helping a friend buck logs for heat for his family.
Saw never stopped running, but the incoming air from the intake and cooling air off the fanwheel what enough to catastrophically change bore diameter. Shrinking the hot cylinder on the intake side, closing it around the skirt.
I still have that piston for pic references.
To me....by photo inspection only, knowing the model, it ate a bearing. Which one? I’ll leave that up to forensics. Most likely one of the mains. A piece of said bearing wedged between the cylinder wall and skirt and perhaps some more made it up through the transfer tunnels.
Straight gassing normally scores the entire circumference of the bore, not just the intake side.
I’m guessing he was given her the ole piss rev test when sh!t went south.
The only other time I’ve ever seen a piston look similar to that is when I cold seized my 066 in -30 temps while helping a friend buck logs for heat for his family.
Saw never stopped running, but the incoming air from the intake and cooling air off the fanwheel what enough to catastrophically change bore diameter. Shrinking the hot cylinder on the intake side, closing it around the skirt.
I still have that piston for pic references.
jr27236
Addicted to ArboristSite
Well hopefully he sends me more pictures, but I can't help feeling bad for the guy. I sold it for $650 (a beautiful 372xpw 32" b/c) I went over this saw so thoroughly before he took it. There is NO way he didn't put gas in it before he used it. Any person would of checked and topped off the bar oil and gas before firing it up. Right???? But I do know that based on how he responded to my question about fuel mixture he said he didn't fuel it and was only using the gas I had in it when I gave it to him is total BS. I didn't have a lot of gas in it and no way near as much needed for 20 minutes of use at WOT. It's like the people I used to stop for DWI....they ALWAYS said they only had two beers/drinks when asked what they drank. Lol
But I can't help feeling I missed something? But I didn't. If I kept this saw I'd be screaming her through rounds of wood without any issue. I know that, but now I have to defend my sale, that what makes me not want to do this anymore.
But I can't help feeling I missed something? But I didn't. If I kept this saw I'd be screaming her through rounds of wood without any issue. I know that, but now I have to defend my sale, that what makes me not want to do this anymore.
Adirondackstihl
Flyz, Fuel & Fotos
You sold an XPW with Meteor cylinder for $650?? Dang!!!
jr27236
Addicted to ArboristSite
I didn't even look. That's a meteor.piston on there??
Adirondackstihl
Flyz, Fuel & Fotos
Don’t know about the piston, but that’s a Meteor cylinder.
I’d be pissed
RIDE-RED 350r
No wing, no prayer
Couldn't be 51.4mm then if that's a Meteor cylinder...unless they started making them recently.
cus_deluxe
Commie Satan turd
That does not look anything like straight gas damage to me.
cus_deluxe
Commie Satan turd
There looks to be no aluminum transfer just looking at the piston, that is all mechanical damage from whatever it was that let go in the bottom end (most likely). As jeremy said, pretty well known failure in 372s.
cus_deluxe
Commie Satan turd
Adirondackstihl
Flyz, Fuel & Fotos
MP = Meteor Piston
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