V4 - Minimize Chances of Broken Rings

[Berdink]

I've read threads where ones say the V4's are prone to rings breaking - catching on the cylinder walls where there's openings.
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Is there anything I can do to minimize that happening?
Like an additive like yamalube or mixing a stronger oil to fuel ratio, or....?

 

[jimmbo]

A lot of the Ring Problems were the Result of OMC moving the Rings closer to the Crown(top) of the Piston. Over Propping, resulting in a too low of Max WOT Rpm, and high Piston Temps adds to the problem. Wrong/Poor Oil can result in Carbon building up behind the Rings preventing them from expanding-contracting
Best ways to avoid/reduce the Risk, is Prop the Engine to run in the Upper Half of the WOT Range.
Use a Good TCW-3 Oil. Myself, that would be BRP or Mercury Oils(that should start an Oil War). Yamaha has some very good 2 Stroke Oils too
Regularly use BRP Engine Cleaner/Mercury Power Tune to remove Carbon from behind the Piston Rings.
Those Engines are Speced to run 50:1 if using Premix. If the Motor has VRO/MRO, the Pump will mix the proper amount of Oil into the Fuel

 

[racerone]

It is a fact that the rings will break at some time!----Simply due to the shape of the top ring.

 

[jimmbo]

It is a fact that the rings will break at some time!----Simply due to the shape of the top ring.

Those Wedge shaped Rings? I think they were call "Pressure Backed", at least by Evinrude. They were first mentioned in the 1970 Model Yr

 

[Berdink]

Do the Wiseco brand pistons fix this issue?
Is it worth upgrading to those in such an old motor?

 

[Mc Tool]

Those Wedge shaped Rings? I think they were call "Pressure Backed", at least by Evinrude. They were first mentioned in the 1970 Model Yr

Yeah , everyone else calls them keystone rings . Lots of motorbike have used them and the only real issue , apart from abuse ,was excessive wear allowing worn thin rings in worn oversize ring grooves to twist and jump out the exhaust port or override the locating pins and poke a ring end out of a port.
You can do stuff to minimise wear or prolong engine life but when its knackered its knackered .
Just use the boat and dont stress out over it ....if it sucks a kumera it wont do all cylinders at once and you'll make it home

 

[Berdink]

...clip...
Just use the boat and dont stress out over it ....if it sucks a kumera it wont do all cylinders at once and you'll make it home

If/when it happens to me, it sounds like many upgrade to Wiseco.

 

[Mc Tool]

If/when it happens to me, it sounds like many upgrade to Wiseco.

Wiseco sure are good slugs , I fitted s set of them to a 70hp Johnson that was melting pistons (bit of a story) ...and it ate them too .....no fault of the pistons . I think their biggest advantage is that they come in larger oversizes that the stock pistons which gives you a couple more "lifes" when rebuilding .

 

[Berdink]

Wiseco sure are good slugs , I fitted s set of them to a 70hp Johnson that was melting pistons (bit of a story) ...and it ate them too .....no fault of the pistons . I think their biggest advantage is that they come in larger oversizes that the stock pistons which gives you a couple more "lifes" when rebuilding .

I read somewhere, and it may be wrong, but thought I read that they dropped the top ring down a little on the piston making it possibly less vulnerable.

 

[racerone]

I have no idea why the stuck with the bad top ring design for 25 years.----Such an obvious defect.

 

[Berdink]

I have no idea why the stuck with the bad top ring design for 25 years.----Such an obvious defect.

So, I could run it until it breaks a ring, but don't I risk when the ring breaks it scouring the cylinder wall, or chipping a portion of a port?
.
We'll see how this motor ends up working out for me, and if I decide to stick with it rather than find a 70hp, I'll likely just do the upgrade during a winter.