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Dave WM

ring gap posistion

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Posted (edited)
10 minutes ago, Captain Obvious said:

So IMHO, the whole drawback to the tapered ring style is that it only works for one piston diameter. If you're only planning to do one or two sizes most of the time, it would be worth it, but if you have no idea what's coming in the door next week, you'd probably just get to be an expert with the spring steel band style.

So I wonder what the NHRA pro teams use?  Those folks build engines in the pits in between runs, so you would have to figure that they don't monkey around with low-buck tools from the local AutoZone (Canuck members read, 'Canadian Tire') store.  Any quarter-mile fans here?

Edited by Namerow

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Maybe this pliers-style is the best option available to shade-tree mechanics like us.  It comes with a set of bands.  You choose the one that matches the diameter of your rings.  I believe that it eliminates the step that's problematic in the wrapped-sleeve types.  It looks like it also allows you to compress right down to the OD of the piston, without having to worry about free play in the tightening mechanism...

GearWrench Piston Ring Compressor Kit.png
 

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I agree. I've not actually used those, but knowing what I know now about the "overlapping band" style, I believe those pliers would be easier to use with a higher probability of success.

The modification I mentioned earlier about removing excess material from my overlapping band would essentially make them more like that pliers style. I think if I removed enough of the band such that there was no overlap, it would be a lot better. Limits the range it works for, but I'm not planning to do a whole bunch of this.

You certainly don't want to buy or make a tapered collar for every size piston in the world.

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6 hours ago, Dave WM said:

Yup. That's the one I was going to buy before I decided I would try my hand at building a better mousetrap. Cheapest I found was on ebay for just under $40 shipped. So it may depend on how much Summit wants for shipping.

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6 hours ago, siteunseen said:

Don't forget to put rubber hose sections over the cap bolts to not scar the the crank.

Got it. Hoover sent me some used condoms along with the other stuff in the care package. They look good, so I'll use them again.    LOL

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Another solution to the ring gap spacing issue would be to use Total Seal's Gapless Rings.  I ran these (perhaps an earlier version) after my initial engine build in '94.  I still staggered the gaps, though not necessary for compression leakage issues.

TS_TechnicalPage1_img_1.jpg

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16 hours ago, Dave WM said:

When I checked this link, I encountered a name that I hadn't heard for 50 years: 'Wiseco'.  When I bought my first motorcycle as a teenager (a Yamaha two-stroke ), one of the performance mods I made was swapping in Wiseco pistons.  Glad to see they're still around and (apparently) thriving.  They have a huge catalog.

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4 hours ago, ETI4K said:

Another solution to the ring gap spacing issue would be to use Total Seal's Gapless Rings.

I've heard good things about those total seals. If I were doing a more in-depth rebuild on this motor, I would have considered those. But for this motor, I'm just honing and throwing stock rings back in.

How did they work for you? You like the way it turned out?

And yes, I'm with you. I would still stagger the gaps too. Even though it seems to matter even less.  Haha!

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Posted (edited)
3 hours ago, Namerow said:

When I bought my first motorcycle as a teenager (a Yamaha two-stroke ), one of the performance mods I made was swapping in Wiseco pistons.

Mine was a Suzuki, but, me too!

And me too!

:victorious:   Suzuki T-350 with Wisecos!!

Edited by Captain Obvious

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Posted (edited)

And the two stroke cylinder had the tapered opening so you could get the rings in.  CO built what is essentially a two stroke engine cylinder.  Maybe  the same for the four strokes.

 

Edited by Zed Head

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CO: There were so many issues affecting my engine's performance back then (such as an undersized exhaust, all stock emissions controls, questionable injectors, etc.) that when I changed over from TS rings to standard design types, I couldn't really tell a major difference at the ball of my foot. 

That said, I was astonished when I did my first 3K mile oil change with conventional rings.  With the TS rings, the oil was CLEAN!  Conventional rings, not close.

Anyway, THIS build gets TS rings again.  BTW, I'm not embarrassed to admit I can fall for the placebo effect.  "Oohh yeahh, those gapless rings are the *hit.  I bet I got another 20HP!!".

Tongue planted firmly in cheek...

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Posted (edited)

I remember two 2 stroke street bike motorcycles. My Dad had a red Yamaha RD 350 and a friend had a Suzuki GT 750. I had a KX 80 and that fast little bike changed my life, damn power band! I can hardly walk now from the wrecks I've had on those two wheelers.

Yamaha RD350 Relaunch Possible as XSR300 Release Date Nears!

Suzuki GT750

 

Edited by siteunseen

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Posted (edited)

Suzuki water buffalo. My RM400 is a lot of fun. I have ohlin shocks, handles great and soaks up bumps very well.100_1211.JPG

Edited by Dave WM
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Posted (edited)

That's a fantastic bike! I rode a YZ490 4 speed once and couldn't keep the handlebars out of my face. That thing was like a rocket. 

I couldn't kick one over now. If it doesn't have a battery I can't start one.

I apologize for getting off point on this guys thread but I need some good memories right now. Thank you for allowing me to play. :beer:

Oh it's YOUR thread! Thank you once again. Cliff

Edited by siteunseen
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21 hours ago, Captain Obvious said:

Got it. Hoover sent me some used condoms along with the other stuff in the care package. They look good, so I'll use them again.    LOL

I sent him a pm. I haven't seen any post lately. I know he works weird spurts of time so I'm waiting on a reply. Can't do without Hoover. 

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8 hours ago, ETI4K said:

I was astonished when I did my first 3K mile oil change with conventional rings.  With the TS rings, the oil was CLEAN!  Conventional rings, not close.

Anyway, THIS build gets TS rings again.  BTW, I'm not embarrassed to admit I can fall for the placebo effect.  "Oohh yeahh, those gapless rings are the *hit.  I bet I got another 20HP!!".

Haha! Thanks for the insights. And I hope it's not all placebo effect. At least the oil cleanliness couldn't have been placebo!

If this were a "build" instead of a "refresh", I'd probably go that route. Maybe on the next one!

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Nice bikes guys! I don't have any pics of my old crop duster in electronic form. I'm sure I've got a bunch on film squirreled away in a box somewhere. If I turn something up, I'll post up a pic.

It was a rocket in it's time. I think the only thing faster was that wacky Kawasaki triple thing.

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I owned a water buffalo for several years.  Rode year round, in the rain, sun, cold, whatever.  Loved every second of it.  Thanks for the posting the pic.  I hadn't thought about that bike in a long time!

Sorry, if I am extending the off-post commentary.  As I've said before, I get easily distracted. especially by fun stuff.

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I would use the Total Seal rings again just for the clean oil aspect, if that's all they were good for.  Also, if the rings do in fact rotate, and if they don't rotate in sync with each other, one could argue the ring gaps may well line up at some point allowing combustion gases a clear shot to the crankcase.  I would love to see real numbers on performance benefits of reducing blow-by, excluding the supposed benefits of not coating intake runners with oil, etc.

Where these rings would really be of value might be in a diesel engine.  I swear the oil in my truck turns black in a hundred miles (WAG, but you get my point).  I can't believe all that carbon is good for the engine, yet they can run over a half-million miles without a lot of trouble.  

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So this is slightly related since an engine is an engine.  I work at an aircraft piston engine overhaul shop and a couple of years ago our engine test cell was rented out to an investigation team looking in to the effects ring gap has on horsepower. The short story is that even at an inch of ring gap the horsepower stayed constant...it smoked worse than a diesel though!

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