Oh Crap!

[czyhorse]

Ok so I am down recovering from hip surgery and decide now is a good time to do the 365 to 372 mod on. my Husky. So I go at it and eventually gets the cylinder off only to find the lower ring was broken. I have so many questions.

did I do this getting the cylinder off? I had it off and had to slide it back on when I heard a ping. I was not shoving and banging it back on. Are rings that delicate?
could it have run with a broken ring?
the rings are really loose, are they supposed to be that loose?
it looks like there is a very slight score in the cylinder head (last picture). It is just barley detectable with a finger nail. The piston does not look damage in any way.
do I need to replace the cylinder head?
can I just put new rings on?
is there a good tutorial somewhere on how to replace rings?

 

[The Shooters Apprentice]

If going from a 65 to 72 cubic inch engine, you would need to replace the jug anyway.
And yes, they will run with a broken ring.

 

[czyhorse]

The only difference between a 365 x-torq and a 372 x-torq is a baffle in the transfers. I was going to remove the transfer covers and grind out the baffle when this came up. I am trying to decide if I just need new rings or if I need a new cylinder too. I’d rather not spend that money if I dont have too. If I do I’ll buy a 372 x-torq cylinder and piston.

 

[The Shooters Apprentice]

I did not realize it was a X-torq saw. I was thinking older. I would try honing that cylinder and seeing how it looked.

 

[huskihl]

The cylinder will be fine. Make sure there are no high spots around those vertical lines. Scuff it off with sand paper.
The piston shows some wear on the intake side probably from sucking some fines through the air filter, but would probably be alright if it needed to be. I’d pick up a set of Caber rings for it, or buy a new Meteor piston, which comes with Caber rings

 

[czyhorse]

The cylinder will be fine. Make sure there are no high spots around those vertical lines. Scuff it off with sand paper.
The piston shows some wear on the intake side probably from sucking some fines through the air filter, but would probably be alright if it needed to be. I’d pick up a set of Caber rings for it, or buy a new Meteor piston, which comes with Caber rings

No high spots. I can barely detect it with my fingernail. Do I need any special tools to put on rings or put it back into the cylinder? I figured I’d get a new gasket too. Anything else? Are there gaskets on the transfer covers?

 

[buzz sawyer]

No high spots. I can barely detect it with my fingernail. Do I need any special tools to put on rings or put it back into the cylinder? I figured I’d get a new gasket too. Anything else? Are there gaskets on the transfer covers?

Best to use some sort of ring compressor. There is a kit that includes adaptors for different dia. pistons as well as a bottom support to hold the piston up while sliding the jug down. I've used one like this for years. https://www.ebay.com/itm/353646546744?hash=item5256fa0f38:g:cP0AAOSwepJXUu7v

 

[billyboy]

A hose clamp and thin piece of plastic will make a good ring clamp. Cheap

 

[Bobby Kirbos]

A hose clamp and thin piece of plastic will make a good ring clamp. Cheap

I took a 1" long piece of 2", SCHD 40 PVC pipe and cut it in half (along its length). It's not always the perfect diameter, but it works, and it was free (scrap from another project).

 

[huskihl]

No high spots. I can barely detect it with my fingernail. Do I need any special tools to put on rings or put it back into the cylinder? I figured I’d get a new gasket too. Anything else? Are there gaskets on the transfer covers?

If you’re only doing it once, a tuning screwdriver will push the rings in with some patience.
No need to replace the base gasket if it comes off in one piece. I believe you can delete it on a 372 and still have ample squish clearance if you want

There are rubber o rings inside the covers. Be careful you don’t tear them, as I don’t believe it’s an item you can buy. I always clean them up well and smear Motoseal on the o rings before reassembly

 

[lostone]

I bought and used these at first but now I just hold the rings with my fingers and slip the cylinder over them, you can make a holder out of a piece of wood to place under the piston to hold it from moving around and make things easier.
https://www.amazon.com/Stens-751-04...9733&sprefix=small+engine+ring,aps,211&sr=8-3The cylinder looks fine, I personally would use some 2000 grit wet sandpaper to smooth it (I know you said you can barely feel it with a finger nail).
https://www.wolfcreeksawshop.com/pr...aly-fits-husqvarna-365xp-372xp-x-torq-372epa/ Theres a set of Caber rings if you decide to go that route.
Ask ten people what they would do and you will get ten different answers, I would sand the cylinder and replace the piston and rings.
No matter what you decide to do MAKE SURE to do a pressure/vac test once it's all put back together or you could be doing all this for nothing.

 

[lostone]

Also make sure when you get the new rings to place them about a inch into the bore (one at a time) and use the piston to square it up and check the ring end gap. Mahle states typical is around .004 per inch of bore diameter which is putting you around .008 on 50mm but I have set mine around .006 and haven't had issue's YMMV, I don't have the specs in front of me so you would have to look it up but I believe Husky called for a max of .020 before a new set of rings are called for.

 

[cookies]

you can squeeze the rings in by hand but you must keep the rings oriented correctly or the pin will break them during install (what sounds like happened to you taking it apart). Fit the rings and compress them correctly then mark them using a permanent marker so at a glance during install you know they are correctly oriented. Scotch brite the cylinder and wash it before installing a new piston/rings.

 

[holeycow]

cover the crankcase with a clean rag wrapped around the rod. Use your fingers to compress the ring. Take your time. I've never used a ring compressor, but perhaps that makes it easier, idk.

 

[holeycow]

you can squeeze the rings in by hand but you must keep the rings oriented correctly or the pin will break them during install (what sounds like happened to you taking it apart). Fit the rings and compress them correctly then mark them using a permanent marker so at a glance during install you know they are correctly oriented. Scotch brite the cylinder and wash it before installing a new piston/rings.

scotchbrite, soap and water, dishwasher, and brakeclean. Then a skim of oil in the cylinder, on the piston, and the ringlands. Try to refrain from twisting the cylinder when you put it on the piston.

 

[holeycow]

That little slotted board is a good idea, but I haven't felt the need to make any yet.

 

[Gord404]

Best to use some sort of ring compressor. There is a kit that includes adaptors for different dia. pistons as well as a bottom support to hold the piston up while sliding the jug down. I've used one like this for years. https://www.ebay.com/itm/353646546744?hash=item5256fa0f38:g:cP0AAOSwepJXUu7v

I bought a set like that from my local Husky dealer about 4 years ago - use them all the time, - about 11$ then.

 

[holeycow]

Do the ring compressors eliminate the fiddling?

 

[huskihl]

2000 grit……..80 grit………..whatever ya got won’t hurt the plating doing it by hand

 

[lostone]

Do the ring compressors eliminate the fiddling?

Yes and no. It helps on some rings that are stiff, however then you have to raise the piston and cylinder all the way in order to get the ring compressor off while trying not to hit the yamabond if you aren't using a gasket. Basically trading one fiddling around for another.