Will rings stay seated if piston removed
 

I would like to remove a piston and inspect the rings. If rings are OK, can I put the piston back in, even if the rings turn a bit, and the rings will still be seated.

Re: Will rings stay seated if piston removed
 

You will be fine.

Harry

Re: Will rings stay seated if piston removed
 

You can remove all the pistons provided you put them back in their original cylinders. If all is well, the rings move while in use. Good luck.

Re: Will rings stay seated if piston removed
 

That's one thing I've always wonder. Do the rings, while the engine is running, rotate or move. If so, why do they tell you to put them on a piston a certain way when originally installing them.

Re: Will rings stay seated if piston removed
 

I hope one of the expert engine machining guys (Ol' Ron or Walt D) chimes in here and explains the action that takes place for the rings to "seat". Do the rings/walls wear a bit? Do they move in the pistons? Always a mystery to me. I know if they don't "seat" properly you can get blow by. Thanks
John

Re: Will rings stay seated if piston removed
 

Are you supposed to be sure the gaps don't line up? Also ring squeezers are available to compress the rings. In the junk I drive that is not a problem. I'm lucky if the piston comes up the same hole it went down in.
clem

Re: Will rings stay seated if piston removed
 

Yes, both the rings and walls wear slighty to accomplish "seating" Yes the rings rotate on the piston. Positioning the end gaps at specified locations is good for only the first few minutes of engine operation.

Re: Will rings stay seated if piston removed
 

the rings dont walk around the pistons, in fact some pistons have dowls inbeded in then where the ring gap is so they cant walk, the rings wear to the cylinders because they are easier and cheaper to repair, compared to boring the block, i use hasting steel vent rings because they seem to work good in a tappered cylinder, they can expand and contract a lot in a worn cylinder with out breaking

Re: Will rings stay seated if piston removed
 

The rings do rotate in the bores while the engine is running,much has been tested to prove this.Rings that are pinned to stop rotation are referred to as pin mill rings this is very common in 2 cycle engines that have ported cyl walls.This pin is used to prevent ring rotation to keep the ring points from rotating and snagging in the bore at the port in the cly.Your post says they are pinned to prevent rotation and you also say they don't walk.Then why pin them? Snowmobiles are a common application.

R

Re: Will rings stay seated if piston removed
 

a lot of the english engines use the pins, basically to make sure the rings are installed with the right ring gap locations, fail safe for hand built engines and for non trained help,

Re: Will rings stay seated if piston removed
 

O K
So I guess this thread is settled

Rings move

Rings don't move
Gaps line up
Gaps don't line up



And Clem still has a problem with pistons going down in one cylinder and coming up in another.
Now, how do rings "seat"?

Re: Will rings stay seated if piston removed
 

That last statement was hilarrious Clem. still laughing on that one. ken ct.:)

Re: Will rings stay seated if piston removed
 

http://www.hastingsmfg.com/ServiceTi...ng_seating.htm

Re: Will rings stay seated if piston removed
 

Cyl are honed to have a cross hatch, the new rings scrub on that cross hatch and lap them self to make a good fit in the cyl. Most of the rings on later engines have a Moly face on the top ring, that is pretty soft stuff, you have to hone the cyl with a fine stone or you'll wear that moly off before the ring get seated. Cast iron rings will seat on about anything. Chrome rings are hard to seat, you have to drive the s-it out of it to make them seat but after they do seat they last longer. Alot of guys make a big deal about lineing up the ring gap. If you just put one ring 180 degrees from the other they will be fine. I have taken more than one engine apart with the rings all lined up, I'm sure thay the were'nt put together that way. I know the 2 cycle rings are pined for a reason. Walt

Re: Will rings stay seated if piston removed
 

I think the rings rotate clockwise in the northern hemisphere but CCW down under. Any of our "mates" on here confirm that?

Re: Will rings stay seated if piston removed
 

Most 4 stroke engines have no pins to hold the rings, at least none that I have ever overhauled. We here in the USA don't always choose words that describe what happen visually but we are what we are. The folks in the Uk use a term called "bedding in" and it refers to the whole engine more than just one specific item. We use break in but nobody wants any thing to break in there. It all boils down to how parts that move against each other wear in a manner that provides the best possible fit for those parts.

If I was taking the time to remove a piston, I wouldn't reinstall worn rings. Now if they are near new, why waste a part that hasn't even bedded in completely yet. It's not a lot more effort to ream the ridge & hone out a bore then install some new rings but thats just my own preference. A lot depends on how much wear has taken place in the bore since the last overhaul. If the wear is minimal then a break of the glaze and some new rings will insure a decent compression. There is some method to the madness if your only doing one slug versus all eight. Ya'll can do however it pleases you if your experience is good with it.

Kerby

Re: Will rings stay seated if piston removed
 

36tbird,
Greetings from down under. I'm not 100% sure which way the rings rotate around the piston (LOL) but I do know that the end gaps line up after some use. In our shop we have noticed this more after an engine has banged it's self to death by detonation. That's if the land between the top and second ring is still in one piece. Subaru, WRX engines for sure, have pins in the oil rings to stop rotation because of the hole in the bore for the piston pin to be removed from the engine.

Re: Will rings stay seated if piston removed
 

Some engines have pins to keep rings from rotating on pistons to prevent ring end gap from being located on the bottom when not running on horizontal bore engines This was to help prevent oil that was in cylinder from getting into combustion chamber. my 2 cents lee34

Re: Will rings stay seated if piston removed
 

My 2 cents worth,

If the ridge around the top is not reamed out you may not even get the piston out.

Whatever you do make sure the pistons 1) go back in the same hole and 2) don't rotate them 180 degrees.