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Rwbutler

Advanced Contributor
No,I don't know why the top ring breaks on 3.5 loppers and crosflow.please tell me your opinion. I need to know cause I'm still running a'79 100 with hi ring pistons.
 
Well the looper motor does not have the ring problem anywhere near as bad as the crossflow.. And the problem shows up primarily in the V4/V6 crossflow not the smaller motors. It happens when carbon builds up on the top ring, be it from cheap oil or bad thermostats and running to cold. As the motor gets older the ring gets narrower and the carbon can fall in behind it. Once that happens the ring can no longer float in the groove, then bang catches the port and breaks. Google the rest and Turn off your autocorrect. It can be prevented but not with muffs. Use BRP engine tune, Yamaha ring free or Mercury powertune, I do not know how long the BRP product will be available. But the other 2 should be for quite a while yet.
 
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That's the way it was taught to me also. Any idea why Racer says it's a design issue?pressure back rings are used in many engines.
 
Because the.problem does not show up until that ring is installed. Older crossflows do not have that problem just the ones with that ring.
 
Probably see it(broke rings)more in the V4 because their more of them out there. Drop a ring in a big V6 and there ain't enough left to tell what happened.
 
I was taught by reps and school that is mainly a cooling problem that makes other problems.The V4-V6 use the same impeller and it move X amount of water at X RPM. The V-4 being 2 cylinders less is more prone to running cold due to t-stat/poppet problems. This leads to lower combustion temps which allows coke to build up in cylinders and exhaust tube. Low quality fuels, some additives and oil not TC-3 rated did not help either.. Most high ringers in my area have either died ,been scrapped or rebuilt years ago. I rarely seen one now, but rebuilt quite a few in the 80's as Johnson would give the customer the parts if they complained...
 
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??----Just draw a picture of the " pressure back " ring in a groove !-----Then visualize what happens to SIDE CLEARANCE when piston / ring / cylinder wall wears.-----Then draw a rectangular piston ring in a groove.-----See what happens to SIDE CLEARANCE when piston / ring / cylinder wall wears.
 
I would take your 100 hp motor and put it on display. You probably have one of the only high ring ones left. How do you not know the upper ring is shaped like a wedge???? Didn't I tell you to google the rest????
 
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racerone said:
??----Just draw a picture of the " pressure back " ring in a groove !-----Then visualize what happens to SIDE CLEARANCE when piston / ring / cylinder wall wears.-----Then draw a rectangular piston ring in a groove.-----See what happens to SIDE CLEARANCE when piston / ring / cylinder wall wears.
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You would have thought if pressure back rings were a bad design they (evinrude,yamaha,johnson,etc) wouldn't still be using them today.One thing for sure,ring breakage is common on crossflows.
 
flyingscott said:
I would take your 100 hp motor and put it on display. You probably have one of the only high ring ones left. How do you not know the upper ring is shaped like a wedge???? Didn't I tell you to google the rest????
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Its original,I bought it in 79, Ran on 89octane or higher ,E/J,oil,turner every year.
 
Rwbutler said:
You would have thought if pressure back rings were a bad design they (evinrude,yamaha,johnson,etc) wouldn't still be using them today.One thing for sure,ring breakage is common on crossflows.
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Yamaha are looper motors. What you are missing is this happens in the V4/V6 OMC crossflow motors. Not the smaller crossflow or the looper motors. I believe you about your motor I would put it on display.
 
flyingscott said:
Yamaha are looper motors. What you are missing is this happens in the V4/V6 OMC crossflow motors. Not the smaller crossflow or the looper motors. I believe you about your motor I would put it on display.
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Im not missing it ,I agree totaly. Racer said it was a bad design,I was wanting to know why he thought the ring was a bad design.right now i dont care. End of post.
 
Rwbutler said:
You would have thought if pressure back rings were a bad design they (evinrude,yamaha,johnson,etc) wouldn't still be using them today.One thing for sure,ring breakage is common on crossflows.
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Now I have a question, Who is still using them. J/E are the same company and cross flow production stopped in 1998. I don't remember Yamaha using them maybe I am wrong about that.
 
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