Piston clip / ring position

[hampshirehog]

I pulled this in to a new thread from 'Piston Fun' as we were unintentionally hijacking that thread.

Trippivot said:

no failures eh? ever? yeah like we all believe that. the tip I gave away freely is true. bad information is the easiest to get.
if the circlip is at 12 and 6 it works like a self lock inside the groove-both ends pushing outward together. anywhere else and the flex of going up and down will pop it right out of the groove one side against another-like a spring. try squeezing one like a c and then squeeze one right on the opening. my point will stick right into your finger. it is a true engine building detail.

20 years and never worried about where the circlip opening is? next you probably like to put the top ring opening gap at 12 and 6 o'clock too??

which is also a no no it is called the thrust surface...

Whilst I agree that you should not reassemble the piston rings at 12 and 6 o'clock I'm not so sure that it's a big no-no. Rings will move around on ther own and I've pulled engines apart that I know were put back properly and found the rings in, or close to, those positions.

The absolutely key thing is that both gaps don't end up in the same place - and the chances of that happening at random, with the rings moving round, must be almost unmeasurable.

Of course, on strokers you have the pegs in the ring grooves to stop this happening. This is to stop the end of the ring poking in to a port and snapping off. If ring position was critical on 4 strokes then I'm sure that manufacturers would put pegs on those pistons as well.

On the subject of pin clips, again I'm not so sure. I've always done it 'right' with the type of clip that is in our GSs but on some bikes (I'm trying to think of a specific model but can't - definitely some early Suzukis though) they use a butterfly clip. In the manufacturer's service book clip position isn't specified.

[Agemax]

as far as piston rings goes its quite easy to get it right, as far as piston pin circlips goes the geezer in question is totally wrong, you cant teach the thick headed!

[sharpy]

No need to start calling people names. If you do what you do and works so be it, We all have our personal "tricks" so let this thread die. Personally i put the spacing of the clip at 12 or 6 position. Its the same as gasket sealant. I use a smear around oil galleries and thats all, why would u when there is a gasket there? Oh yeah ive been building engines for 35 years. Dont make me a expert but i know what im doing. (i think) So bottom line if it works for you so be it he was only offering advice. If someone cares to choose to use it or not so be it. So die thread, die you useless thing.

[Agemax]

No need to start calling people names. If you do what you do and works so be it, We all have our personal "tricks" so let this thread die. Personally i put the spacing of the clip at 12 or 6 position. Its the same as gasket sealant. I use a smear around oil galleries and thats all, why would u when there is a gasket there? Oh yeah ive been building engines for 35 years. Dont make me a expert but i know what im doing. (i think) So bottom line if it works for you so be it he was only offering advice. If someone cares to choose to use it or not so be it. So die thread, die you useless thing.

ok each to their own but why have a go at me for name calling then come out with that reply? your as bad as i am lol

[Footy.]

I pulled this in to a new thread from 'Piston Fun' as we were unintentionally hijacking that thread.

Trippivot said:

no failures eh? ever? yeah like we all believe that. the tip I gave away freely is true. bad information is the easiest to get.
if the circlip is at 12 and 6 it works like a self lock inside the groove-both ends pushing outward together. anywhere else and the flex of going up and down will pop it right out of the groove one side against another-like a spring. try squeezing one like a c and then squeeze one right on the opening. my point will stick right into your finger. it is a true engine building detail.

20 years and never worried about where the circlip opening is? next you probably like to put the top ring opening gap at 12 and 6 o'clock too??

which is also a no no it is called the thrust surface...

Whilst I agree that you should not reassemble the piston rings at 12 and 6 o'clock I'm not so sure that it's a big no-no. Rings will move around on ther own and I've pulled engines apart that I know were put back properly and found the rings in, or close to, those positions.

The absolutely key thing is that both gaps don't end up in the same place - and the chances of that happening at random, with the rings moving round, must be almost unmeasurable.

Of course, on strokers you have the pegs in the ring grooves to stop this happening. This is to stop the end of the ring poking in to a port and snapping off. If ring position was critical on 4 strokes then I'm sure that manufacturers would put pegs on those pistons as well.

On the subject of pin clips, again I'm not so sure. I've always done it 'right' with the type of clip that is in our GSs but on some bikes (I'm trying to think of a specific model but can't - definitely some early Suzukis though) they use a butterfly clip. In the manufacturer's service book clip position isn't specified.

I have been building engines of all kinds for 40 years now. This idea of placing the circlip gap in a particular position seems to be a notion invented by some self elected engine building "experts".

I have never seen such a recommendation from the actual engine manufacturers. The inertia issue is not a player here, particularly with the very light wire clips as in GS's.

What is important is the circlip design in relation to the natural resonance of the engine. All engines produce vibrations of certain frequences, and if these match the natural resonance of the circlips at particular revs, the circlips will start to vibrate in sympathy and can then "jump" the groves. But this issue is delt with in the developement stage of the engine. The wire thickness/hardness being adjusted to alter the natural resonance.

It's the same principal as a particular musical note shattering a glass. The glass vibrates to the frequency till it breaks.

I am sure that as such a circlip gap position is not specified in GS engine manuals, many engines have been built over the years with the gaps in the "wrong" position! So where are all the reports of circlips jumping out? If you have had a circlip come out you have another issue. Usually it because someone has re-used an old clip. This should "NEVER" be done with wire circlips.

The ring position issue is also a myth. Hepolite pistons researched this years ago and found that rings rotate quite quickly, again depending upon the natural harmonics of the particular design. This is why two strokes need pegs to stop ring rotation.

In 40 years of looking at worn four stroke bores, i have yet to see any straight top to bottom ridge left where the ring gap is, that would show non rotating rings. This should be very obvious in the area of maximum wear at the top of the bore, where only the top ring travels if this notion was true.

In the case of multipart oil rings, "THEN" the gaps of the rails and expander should be fitted at 120 degree intervals.

Footy.

[renobruce]

I've never seen anything posted before regarding the position of the circlips. I couldn't tell you where mine are. I just put them in any old way. I hope it doesn't matter...

[reddirtrider]

I have been building engines of all kinds for 40 years now. This idea of placing the circlip gap in a particular position seems to be a notion invented by some self elected engine building "experts".

I have never seen such a recommendation from the actual engine manufacturers. The inertia issue is not a player here, particularly with the very light wire clips as in GS's.

What is important is the circlip design in relation to the natural resonance of the engine. All engines produce vibrations of certain frequences, and if these match the natural resonance of the circlips at particular revs, the circlips will start to vibrate in sympathy and can then "jump" the groves. But this issue is delt with in the developement stage of the engine. The wire thickness/hardness being adjusted to alter the natural resonance.

It's the same principal as a particular musical note shattering a glass. The glass vibrates to the frequency till it breaks.

I am sure that as such a circlip gap position is not specified in GS engine manuals, many engines have been built over the years with the gaps in the "wrong" position! So where are all the reports of circlips jumping out? If you have had a circlip come out you have another issue. Usually it because someone has re-used an old clip. This should "NEVER" be done with wire circlips.

The ring position issue is also a myth. Hepolite pistons researched this years ago and found that rings rotate quite quickly, again depending upon the natural harmonics of the particular design. This is why two strokes need pegs to stop ring rotation.

In 40 years of looking at worn four stroke bores, i have yet to see any straight top to bottom ridge left where the ring gap is, that would show non rotating rings. This should be very obvious in the area of maximum wear at the top of the bore, where only the top ring travels if this notion was true.

In the case of multipart oil rings, "THEN" the gaps of the rails and expander should be fitted at 120 degree intervals.

Footy.

I agree. Glad you posted it and saved me some typing.