Where’d the other ring go? 009L 1120 series

[PhattyMatty]

It runs — don’t know how with ~30 - 45psi compression. New piston is on the way — the cylinder looks okay to me… but seriously

WHERED the ring go??

 

[pioneerguy600]

You best spend some time working on that damage below the exhaust port or it will tear up a new piston. Remove all high spots and re check the bevel on the bottom of the port floor so a ring does not catch again. Look in the muffler for any bits of the ring that disappeared.

 

[spuldup]

Well the ring went several places. Some in the muffler, some in the crank. Big cleaning ahead of you. Cylinder may not be salvageable because you'd have to lower the exhaust to clean that snag up, which may make it run like a turd.

 

[thompsoncustom]

looks like he just has to lower the bottom of the exhaust port which won't hurt performance unless it's to the point that the piston is above it at TDC and it's free porting and even than you can get by with just a little free porting on some saws and be fine.

 

[pioneerguy600]

No need to lower the port just clean off all the high spots, I have done plenty with just using a chain file those saws are still running fine many years after. As long as the cylinder wall is flush or just a bit lower than the rest the piston and rings will pass over it with no problems, many of the cylinders I run several old rebuilt saws that would have been discarded by many as unuable but in reality they have provided hundreds of hours of reliable cutting, these are not race saws just saws that cut firewood for their owners. I have a John Deere 56 that has 30% of the cylinder wall below the exhaust port lowered .010 or thereabouts lower than the rest of the cyl wall, 7/8 inch below and the full width of the ex port the plating was destroyed by the previous owner running the saw far too lean for extended periods, the transfer was very thick and when removed the plating was gone. Cleaned it up and a new piston and rings the saw makes 175 lbs comp and has run for 5 years on firewood duty, 5-6 cords bucked per year and storm cleanup in between. So many cylinders are tossed unnecessarily that just the correct cleanup can save them , damage below the exhaust port don`t hurt the performance much if any as long as the piston and rings ride over it without catching or rubbing on high spots. I have even seen saws with free porting run very well so I had no issues with a saw that has just a few nicks below the exh port.