Husqvarna 455 pistin ring mystery........????????.........????????

[david newbie]

I picked up a 455 that I needed for a few parts. However, it was in pretty nice cosmetic condition so I decided to try and rebuild it, ( low compression). It's a little odd, the cylinder looks good to me, and the piston doesn't look too bad either. However,, the ring seems quite worn. However, It does not seem to be a split removable ring!!?? Did it simply get fused, or is this how they were made? I guess I will have to replace both piston and ring. This will be my first clamshell rebuild. Ive never replaced seals before either. They did not blow any bubbles when I pressure tested with soapy water. Maybe this is a good chance to try learning to replace seals? ( a little nervous, as I'm fairly good at messing things up)

 

[ballisticdoughnut]

That ring is stuck from carbon buildup. Remove ring, clean grove, and install new ring. You’ll be good to go.

 

[david newbie]

That ring is stuck from carbon buildup. Remove ring, clean grove, and install new ring. You’ll be good to go.

I cant see how to remove ring!! there's no split or open spot. Isn't there usually a gap!?

 

[ErnieG]

Its split rite here ...
Ernie

 

[Jasonrkba]

Soak it on diesel or something. It may loosen up. The seem can be hard to find sometimes.

 

[david newbie]

You guys have better eyes than me!!!

 

[david newbie]

And any repossess to my question about seals? Or just leave those alone?

 

[Jasonrkba]

The seem will always be at the locating pin.

 

[Jasonrkba]

I'd do the seals. Just my opinion.

 

[cookies]

I'd reuse the seals, soak the piston in atf/acetone a day or three until the carbon starts falling off then use a sharp pick at the locating pin hole to pry the ring free, it may snap coming out. clean the piston's ring groove and install a new ring. Ask if possible what oil was used in their fuel at what ratio.

 

[singinwoodwackr]

You guys have better eyes than me!!!

Zoom is your friend

 

[leaf]

Just trying to help... When you put the new ring in, use assembly lube (a specific kind of oil) or just decent synthetic motor oil to lubricate the ring at install. I also use assembly lube on the wrist pin and down at the crank. Keep everything super clean as you put the cylinder onto the piston.

 

[cscltd]

I would replace the little rubber base gaskets that they use also. Guy may have been using cheap oil and old fuel?
Rub seafoam or similar to remove varnish on piston skirt before putting back together

 

[JKNW]

I've had good luck heating the piston from the inside with a propane torch to unstick rings. I got my 455 cheap with the same stuck ring issue, I ended up putting an aftermarket pop-up piston and a seal set in it for less than 40 bucks.

 

[singinwoodwackr]

Just trying to help... When you put the new ring in, use assembly lube (a specific kind of oil) or just decent synthetic motor oil to lubricate the ring at install. I also use assembly lube on the wrist pin and down at the crank. Keep everything super clean as you put the cylinder onto the piston.

I use mix oil

 

[Gord404]

I use mix oil

Me too

 

[david newbie]

I managed to get it off after a 2 day soak with sea foam , torch, dental pick. hammer, steamroller, etc. Of course I broke the ring.... Found a caber on ebay for 9$. Hopefully I can put it back together and get it to run without leaks.......

 

[bwalker]

I managed to get it off after a 2 day soak with sea foam , torch, dental pick. hammer, steamroller, etc. Of course I broke the ring.... Found a caber on ebay for 9$. Hopefully I can put it back together and get it to run without leaks.......

I would wager that that piston ran very hot judged by the coaking present. This can be caused by a very worn ring, but in this case the piston doesn't show alot of wear. The other things that cause this are lean carb settings, excessive load with a dull chain and using the wrong type of oil. Or a combination of the above.
Given you have the saw torn down I would absolutely replace the crank seals.

 

[Tobystihl]

I boil pistons in a pan of water, often does the job