330 Piston rings

[karla48]

Does anyone know why some Homelites 330 use thin Piston rings (.024) and others use (.047) rings, and is there an easy way to tell from the UT#'s or manufacture years which 330's have which?

[tommyhnavix]

Not sure why, but you could remove the muffler for a peek to see which rings are used. There may be a difference based on newer or older models. I think newer saws have higher UT numbers. So maybe above a certain number they only use the one style

Tom

[karla48]

Tommy, Thanks for the reply, and that is what I'm thinking too! I keep checking all the IPL drawings for the different UT#;s and have not figured it out yet, just a curious thing! Maybe as I add more 330's to my fleet, I will get a better clue.

[dynodave]

I know of this engine design principle that when some piston rings if 1: to heavy and then when
2: the piston speed exceeds a particlular feet per second velocity
3: the ring will unseat from the piston ring land due to the momentum and I think they call it flutter. It causes a loss of power at high RPM.
Higher tension on thinner rings is the fix.

Of course only guessing.... but it popped up in my head as a possible explanation.

I can pull the muffler off my UT 10604A and give you a data point for the research value.

I was reviewing all the 330 posts since my new donated saw was supposedly "no spark"
tests out at 125psi compression, It does have spark and with some mix in the spark plug hole... it fired up......wooo hoooo
Might just need a carb kit (ZAMA) to keep running.

ADDED: I think my rings are the .024" ones..p/n 96510 ?

[karla48]

Dynodave, Thank you for the information, neat stuff!

[chainsawlady]

Tribulation
I still have Phelon points for the XL=Homelite series and 2 of the condensers. When Homelite was taking them off of the parts list I must have lost my mind as I ordered plenty.
chainsawlady