Piston ring positions - How critical???

[hampshirehog]

The rings will move, though they won't spin 'round and round'. May be up to 15 degrees or so and then they'll stay put as they bed in. I used to be real finicky about this years ago but once I realised they shifted only put them in roughly and it makes no difference. (Except when using old rings as they will have bedded in where they were when you split the motor, but even then you'll never line them up perfectly)

The reason for the 120 degree split is for the oil ring. Yeah, I know it's not there for compression but it can't do any harm can it.

[tkent02]

IF they do move the likely possibility of the gap landing IN the exhaust port is, at the very least, possible.

I'm sorry, this is a four stroke, the ports are in the head.

[TheCafeKid]

I was just thinking of this exact same scenairo...and let me add a little more "what if". IF they do move the likely possibility of the gap landing IN the exhaust port is, at the very least, possible. Now, add to that the exhaust temps on an "open" end of the ring (where there is less material to dissipate the heat) and "is there a chance of melting the end of a ring"?
....more food for thought.....

The rings, from what i can tell, never see beyond the jug, so its not possible for them to end up over the ehaust port.

180 degrees would be ideal if there were only TWO rings, since there are 3, its 120. My logic says the rings themselves have no idea where they are in relation to the cylinder. The cylinder is symetrical in all directions, so as long as they are 120 degrees apart they dont care, nor does the motor care where they are lined up.

[bwringer]

Oh, fer Pete's sake...

Go ride the snot out of the thing and don't trouble yourself one more moment about this.

As long as the ring gaps are not lined up, you're fine. It won't make the slightest difference to compression or oil consumption. The important part is that the gaps are staggered, not precisely where they point.




Oh, by the way, I've successfully rebuilt four GS850 engines and top ends, along with lots of other bikes and cars.

[TheCafeKid]

Oh, fer Pete's sake...

Go ride the snot out of the thing and don't trouble yourself one more moment about this.

As long as the ring gaps are not lined up, you're fine. It won't make the slightest difference to compression or oil consumption. The important part is that the gaps are staggered, not precisely where they point.




Oh, by the way, I've successfully rebuilt four GS850 engines and top ends, along with lots of other bikes and cars.

Thank you! Words of wisdom, words of wisdom. There is no magic behind where the rings point. Some guy at Suzuki, Clymer or Haynes layed out the diagram, and it just so happens thats where he pointed them in it. At least thats the way i look at most of this stuff. Judging by the design of everything else, were they supposed to be pointed in a specific direction, there would be marks on the jugs, the way they mark alignment of everything else that requires it on the motor

[hampshirehog]

Some guy at Suzuki, Clymer or Haynes layed out the diagram, and it just so happens thats where he pointed them in it.

But don't forget, according to Haynes, the bogeyman will get you if you dare to touch those screws on your carbs

[juicydangershow]

Well if I decide to tear it down again, I would have the opportunity to get all the great pics I should have gotten (and posted) along the way in the first place!

The head gasket was rubberized, but I am not sure if it was rubberized metal. It had 4 crush rings for the cylinders, 4 copper crush rings around the corner studs and 4 rubberized washers that sit on top of the copper holes. It was a Vesrah brand. The metal rings around the cylinders where the same size on both sides of the gasket, the copper rings on the corners were wider on one side. I placed the wider side UP and put the little rubberized washers on top of those copper holes. Vesrah should label the gasket TOP side and give some indication about the washer placement and orientation (they were rubberized metal, with more rubber on one side). I placed them rubberized side up. Those washers are a pain to make sure they stay placed when seating the head. I often wonder if they ended up moving on me at the last moment.

If I have to get another head gasket, I would definitely look for a brand that had everything built into the gasket.

[TheCafeKid]

Well if I decide to tear it down again, I would have the opportunity to get all the great pics I should have gotten (and posted) along the way in the first place!

The head gasket was rubberized, but I am not sure if it was rubberized metal. It had 4 crush rings for the cylinders, 4 copper crush rings around the corner studs and 4 rubberized washers that sit on top of the copper holes. It was a Vesrah brand. The metal rings around the cylinders where the same size on both sides of the gasket, the copper rings on the corners were wider on one side. I placed the wider side UP and put the little rubberized washers on top of those copper holes. Vesrah should label the gasket TOP side and give some indication about the washer placement and orientation (they were rubberized metal, with more rubber on one side). I placed them rubberized side up. Those washers are a pain to make sure they stay placed when seating the head. I often wonder if they ended up moving on me at the last moment.

If I have to get another head gasket, I would definitely look for a brand that had everything built into the gasket.

Actually i think that this gasket is per OEM design. My 8v motor gaskets are all the same, or similar, to yours. they are Vesrah as well. However the Vesrah headgasket for Mike's 82 1100E that Steve and I have been working on is one peice, with no rubber or copper anythings. I think THAT is part of the 16v design. However, I DO agree with you on them marking top and bottom, since we're talking about specifics on things, the manual CLEARLY notes the gasket is usually marked TOP. None of the ones i have seen have been marked so. But, ive never had a leak from one of them yet either

[psyguy]

i had the same gasket set

Those washers are a pain to make sure they stay placed when seating the head. I often wonder if they ended up moving on me at the last moment.

yeah, quite a pita

[heathen]

i just rebuilt my 750 topend. the rings don't care where they are as long as there not lined up. also had to take mine back apart after running it for about an hour (oring moved in groove causing a oil leak) rebolted every thing but had to torque the head bolts 5 pounds over to seal so as not to have an oil leak. bike runs great so don't worry about where you positioned the rings. this is the first bike i have done but have built many drag race motors and as long as the rings are spaced apart it don't matter. as far as the rubber washers that go on the 4 corners. my original ones (36,000 miles) had droped down the holes and were sitting between the cylinder and the case. no orange rubber left on them. at first i thought that was where they went until i checked them and they fit in the head gasket.

[Steve]

IF they do move the likely possibility of the gap landing IN the exhaust port is, at the very least, possible. Now, add to that the exhaust temps on an "open" end of the ring (where there is less material to dissipate the heat) and "is there a chance of melting the end of a ring"?

Just how is it supposed to land in the exhaust port? The exhaust port is downstream of the exhaust valve, and methinks that if you have the ends of your rings landing in the exhaust port, you have some things that are considerably more important to worry about.

For those that did not catch on to the original post, the talk about keeping the rings out of the ports was concerning 2-stroke engines.
Our 4-stroke engines do not have ports in the cylinders.

[rustybronco]

where are the oil control ring gaps?
they should be spaced ABOUT 180 degrees from where you placed the 1st and 2nd rings with the gaps (spacer, top, bottom) of the oil ring staggered ABOUT 45 degrees or more.

if the oil control ring gaps are ABOUT 180 degrees from the placement of your top and 2nd rings.
the DAYUM thing will be just fine!!!!!!!!!!!!!!!!!!!

IF you are loosing sleep, take it apart.

[flyingace]

You know what, it's easy to say 'I'd take it all apart again', but if it isn't necessary, that's just plain foolish. There's nothing that's going to harm your bike. Run it and see what happens. And don't waste your $ on another head gasket!

Let me tell you a story about my 'top end' rebuild. I had a spare engine, so I took out the pistons. I cross-honed the cylinders and bought a $25 set of rings on Ebay. I had a set of feeler gaugues and took all eight pistons and mixed/matched them so they were the nearest to tolerance of the cylinders I could get. Then I put rings on pistons and pistons on rods and then the block over them. Then I used the old head gasket cause $85 was too much to replace a perfectly good 25 year old gasket. That was 8,000 miles ago and it still runs great.

Rebuild everything because they aren't exactly perfect!? Don't make me laugh.

[TheCafeKid]

You know what, it's easy to say 'I'd take it all apart again', but if it isn't necessary, that's just plain foolish. There's nothing that's going to harm your bike. Run it and see what happens. And don't waste your $ on another head gasket!

Let me tell you a story about my 'top end' rebuild. I had a spare engine, so I took out the pistons. I cross-honed the cylinders and bought a $25 set of rings on Ebay. I took a set of feeler gaugues and took all eight pistons and mixed/matched them so they were the nearest to tolerance of the cylinders I could get. Then I put pistons on the rods and then the block over them. Then I used the old head gasket cause $85 was too much to replace a perfectly good 25 year old gasket. That was 8,000 miles ago and it still runs great.

Rebuild everything because they aren't exactly perfect!? Don't make me laugh.

I have to agree. If its not passing oil thru the seals or rings, ride it. I am one that sweats over odd ball noises i hear, but the more and more i get used to working on these things, the less i worry about it. Its going to break something at some point. I dont sweat the top end anymore, because now i can repair it. I plan on crackin a spare motor i have open to teach myself how to rebuild the bottom end on these too. Thats the only part of the bikes I worry about now. If something in the top end blows, oh well, I will fix it. But if its something in the top end that can damage the bottom end, I start worrying...lol

[lecroy]

Ah, I loved working on those old scavanged port motors as a kid.... Times were simpler...

I pay close attention to the bore, piston clearance and ring gaps. I also keep close tabs on the deck height. My eyes are getting pretty bad now and so I tripple check that the rings are right side up.

I think I am pretty anal about motor assembly, except I do not use the correct tools when it comes to the rings. I still put them on by hand. A big no-no in anyone's book. Worse, I do not use a ring compressor to put the block on. I do it all by hand and have paid the price many a time when using copper base gaskets... Or as I like to call them, the slice-o-matic. Doing this all by hand, I eyeball the rings but they move as I compress them one by one and slide them in. Ryan showed me his home made PVC pipe compressors. I swore I would try this on my last project, but still did it by hand. This would help keep things in place and make the job much simpler.

I did a little search and read this article. I agree with it for the most part...

http://aircooled.net/gnrlsite/resource/articles/pcrops.htm

I think Ray works for a piston company. He could maybe shine some real data on this.