Can this Cylinder be salvaged!!!
- Thread starter KTM640
- Start date
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I don't see any relationship in this article to what this P&C shows.
If I'm interpretting this correctly, the damage you see to the crown of the piston and squish land of the cylinder is due to detonation, which in turn eroded the metal away. This detonation also can beat out bottom end bearings, be it on the rod or crank ends. Am I getting this correctly?
Hit your self in the head with a ball peen hammer a couple hundred times ...J/K
You get the picture
In this case, I'd say several tens of thousands.
PB
Addicted to ArboristSite
First off the disclaimer, I am not an expert, that's why we have Lakeside and Spike.
I have seen this before with some of my project saws and they were all the result of a bad bearing somewhere.The crowning around the edge is from taking a beating from something. Detonation wouldn't cause a gouge in the side of a piston, something was definitely in the saw.
First off the disclaimer, I am not an expert, that's why we have Lakeside and Spike.
I have seen this before with some of my project saws and they were all the result of a bad bearing somewhere.The crowning around the edge is from taking a beating from something. Detonation wouldn't cause a gouge in the side of a piston, something was definitely in the saw.
The detonation is the start.....Then something lets enough slop (bearing ect) that the piston hits the head and hammers it self to death...
PES+
Addicted to ArboristSite
Are both the ring stop pins still in the piston?....
It does look like it may have been small end bearing failure but they rarely come loose and get caught in the transfers but it is possible.
It used to happen often in Macs but that was due to the needles being in the piston rather than caged on the pin.
The piston side damage looks VERY familiar....we used to call it the dreaded
needled the block syndrome
Whatever the object was it stayed in the combustion chamber long enough hammer it silly until it developed hot spots and detonation took over from there.
If it was straight up detonation there would be more pronounced crowning up at the edge of the piston crown.....I'll dig some out when I get a chance and show you the dangers of very low octane mixed with very tight squish bands.
Clean up the cylinder and see how bad the combustion chamber is......
It does look like it may have been small end bearing failure but they rarely come loose and get caught in the transfers but it is possible.
It used to happen often in Macs but that was due to the needles being in the piston rather than caged on the pin.
The piston side damage looks VERY familiar....we used to call it the dreaded
needled the block syndrome
Whatever the object was it stayed in the combustion chamber long enough hammer it silly until it developed hot spots and detonation took over from there.
If it was straight up detonation there would be more pronounced crowning up at the edge of the piston crown.....I'll dig some out when I get a chance and show you the dangers of very low octane mixed with very tight squish bands.
Clean up the cylinder and see how bad the combustion chamber is......
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PB
Addicted to ArboristSite
Thanks Ultra, that post is the reason I joined AS, to learn something.
As Pes+ said.......Seen that before...........There are so many things that can go a muck........
Alot of the answers are here on the site.......
PES+
Addicted to ArboristSite
I wonder
Maybe the PO took the diesel in race saw talk seriously?
I have seen stranger things
Maybe the PO took the diesel in race saw talk seriously?
I have seen stranger things
RiverRat2
Serio Tree Freak
LOL!!!!!! I believe that!!!!!!!! looks like scrap to me!!!!!!
PES+
Addicted to ArboristSite
Had a thought
I once had a plug self destruct and the damage looked like that minus the detonation damage so you may have damage from both the ground electrode and the center electrode coming loose and then someone just replaced the plug without fishing out the loose bits
I once had a plug self destruct and the damage looked like that minus the detonation damage so you may have damage from both the ground electrode and the center electrode coming loose and then someone just replaced the plug without fishing out the loose bits
lawnmowertech37
Addicted to ArboristSite
could that be a possible fuel related problem to cause that type of build up on top of the piston i think it could be possible ethanol issue
Lakeside53
Stihl Wrenching
It's mechanical damage... something either came loose in the lower end or passed down the intake, was spit up to the top and hammered around for a while.... at full throttle even a 1000 dents only takes 4-5 seconds...
and.... loose the shielded bearings (or their shields) - that was not a good move on Stihl 044's - and they quickly went back to open bearings... Never have come accross them in the 064.
and.... loose the shielded bearings (or their shields) - that was not a good move on Stihl 044's - and they quickly went back to open bearings... Never have come accross them in the 064.
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Freakingstang
Doctor Freakinstein
looks like the remnants of every big end bering failure I've seen. i've got a 268xp here that is beautiful with a beautiful cylinder----wint a pin dent in it..... You pulled and tugged on the rod, did you spin in around a couple times, any kind of resistance in the rod pivoting on the crank is bad news......
KTM640
ArboristSite Operative
Freakingstang, I've done several full rotations on the rod while looking at the bearing and found all the rollers present without any resistance. I did the pull test and there was no play up and down as I rotated the bearing.
This was a basket case and did not include the wrist pin bearing, but there is a witness mark on one side of the upper end of the rod where it looks like the piston was rubbing against the rod. I do have the wrist pin and will take a picture. Looks like a normal wrist pin with wear marks form the bearing.
The crank bearings also feel smooth and I think that the shields saved those from the projectile.
Jon
This was a basket case and did not include the wrist pin bearing, but there is a witness mark on one side of the upper end of the rod where it looks like the piston was rubbing against the rod. I do have the wrist pin and will take a picture. Looks like a normal wrist pin with wear marks form the bearing.
The crank bearings also feel smooth and I think that the shields saved those from the projectile.
Jon
Lakeside53
Stihl Wrenching
If it's not from the bottom end, it most likely came in though the carb... Some chance something was dropped down the plug hole OR, if it had no muffer screen, got in through the muffler.
Or maybe someone didn't like him and dropped in small ball bearing...:greenchainsaw:
And are you 100% sure this piston/cylinder came from that bottom end? Scraping in the bottom is not proof;many case are like that.
Or maybe someone didn't like him and dropped in small ball bearing...:greenchainsaw:
And are you 100% sure this piston/cylinder came from that bottom end? Scraping in the bottom is not proof;many case are like that.
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