I need some feed back.Take a look at these photos, it looks like the piston ring hung up on the cylinder porting and poped off a portion of the piston. Thanks for your help!
Any body had problems with piston rings hanging up on cylinder porting?
- Thread starter WFOPOWDERHOUND
- Start date
Did the ring spin on you? Check if the pin is still there.
It's hard to tell from the pictures, but it looks like some detonation around the outside of the piston. That can cause the top of the piston to fracture off.
I have hooked rings before... either from putting the pistons in wrong or from having the locator pin come out which is what marcuso is suggesting.
sled_guy
I have hooked rings before... either from putting the pistons in wrong or from having the locator pin come out which is what marcuso is suggesting.
sled_guy
Need more info. New cylinders? Maybe not chamfered enough? New pistons? Did you put them in backwards? I don't think the piston snagged, I think the ring snagged. Is the ring bent?
need to take out the pistons and see what you see.....did the locating pin for the rings come loose?....has this engine been run for a while?...could the rings have been installed upside down?....i don't think that a ring snagged and popped off the top of the piston....detonation and the subsequent softening and weakening of the circumferance of the piston with the piston material above the rings breaking off, getting jammed in the ports, causing the most of the damage...notice that the damage is at the outlet to the exhaust, typically the hottest place on the piston...combined with detonation heat is a good receipe for piston failure....if the locating pin for the rings is missing, the open ends of the ring would migrate around the piston until reaching a port, and then snag....take a look at that aspect and repost what you see............
G
Gimpster
Guest
Exhaust side ? I would say lean mixture made it hot
----- Gimpster -----
----- Gimpster -----
Hot Hot Hot!!!!!!
I think the outside half inch of the piston surface was very hot before failure. It also has no soot what so ever which also leads to a very hot conclusion. Molten aluminum everywhere is a dead giveaway that is was really hot!
I think the outside half inch of the piston surface was very hot before failure. It also has no soot what so ever which also leads to a very hot conclusion. Molten aluminum everywhere is a dead giveaway that is was really hot!
H
H2SNOW
ACCOUNT CLOSED
don't you mean muratic acid ???
Holes?
We have seen that kind of aluminum slag flow well into the exhaust port. Happens with lean jetting which is indicated by how clean everything is. It is to clean except for the melted slag. IMHO The ring land breaking is just the symptom of a very hot crown.
We have seen that kind of aluminum slag flow well into the exhaust port. Happens with lean jetting which is indicated by how clean everything is. It is to clean except for the melted slag. IMHO The ring land breaking is just the symptom of a very hot crown.
It looks like that baby took a huge gulp of its own coolent.
H
H2SNOW
ACCOUNT CLOSED
Engine history ~
This is a new top end, 860 kit on an 800r ski doo rev. never made it onto the trailer. mixed the fuel 150:1+ the oil injection, 460 jets. pulled it out of the garage to make sure the track was running true enought to go riding tomorrow. run it up to 6000 about three times and on the why down from from the third run it bound up around 4000 rpms.
I know the rings were not up side down, they wouldn't fit into the pistons that way, they're beveled. the pistons are also duel ringed for what its worth.
I checked the plugs 3 times prior to checking my track and each time I took the plugs out there was oil residue on the end of each plug.
You can't see it in the photos but the ring pin is right where the piston blew out, (at the largest point of blow out) it also looks like the ring had rotated about 1/8 pat the ring, not sure how that would happen? I will find out more tomorrow when I pull it apart. The cylinder walls dont look too bad, I'm woried about the lower end now!
This is a new top end, 860 kit on an 800r ski doo rev. never made it onto the trailer. mixed the fuel 150:1+ the oil injection, 460 jets. pulled it out of the garage to make sure the track was running true enought to go riding tomorrow. run it up to 6000 about three times and on the why down from from the third run it bound up around 4000 rpms.
I know the rings were not up side down, they wouldn't fit into the pistons that way, they're beveled. the pistons are also duel ringed for what its worth.
I checked the plugs 3 times prior to checking my track and each time I took the plugs out there was oil residue on the end of each plug.
You can't see it in the photos but the ring pin is right where the piston blew out, (at the largest point of blow out) it also looks like the ring had rotated about 1/8 pat the ring, not sure how that would happen? I will find out more tomorrow when I pull it apart. The cylinder walls dont look too bad, I'm woried about the lower end now!
well there ya go. Pistons in backwards. Ring end gaps should be towards the intake side.
yup. true dat. Gap is on the intake..
hone the cylinder a bit that should do the trick
If these cylinders were bored, then the ports should have been chamferred slightly back to keep rings from catching ports.
