Broken piston rings

[domaotc]

I've broken about 4 rings trying to get the pistons back in the block despite using a tool that is supposed to ease them in. This is the lower ring on an '82 9.9 evinrude. 3 questions:

1. Is there a method I should be using that someone can recommend?
2. I now have extra top rings and am wondering if I can use them in the lower groove?
3. Is there a cheap after market for rings? I hate paying $25 for a set when I only need the lower ring.

I am not a mechanic and I do not need this engine as it is just a project I thought would be a good way to learn some engine basics. If I get this engine to run, even if poorly, I will be ecstatic.

 

[racerone]

The top ring and the bottom ring are different .---These rings do not interchange at all.---------Are you using any kind of ring compressor ?-------Automotive style ??----Start the piston into the cylinder.----I use a small screwdriver and line up the pin in the groove.---------Push on the ring till it goes in the cylinder.------Zero broken rings on 9.9 models on many motors.---And no the screwdriver does not damage the ring in any way !

 

[flyingscott]

I agree stop using the ring compressor. How are the rings different never had to rebuild on of these. I am just curious as they don't list 2 different part #s for them. I have seen sets of rings say top but that is where they face in relation to the piston.

 

[racerone]

The top ring has the wild taper / angle just like the V-4 crossflows.----The bottom ring does not.

 

[domaotc]

Here's the ring compressor I tried to use:
http://www.amazon.com/SE-Tools-10-P...31803&sr=8-29&keywords=piston+ring+compressor
So I definitely cannot use the top rings in the bottom groove?

 

[flyingscott]

Alright thank you for the info. No the rings cannot be interchanged. Put the piston in like racer said by hand it is very easy you will be surprised how fast and easy it will go. The problem with the compressor is if the ring hangs up and sticks out just a little it breaks. You also run the risk of chipping/breaking the ring groove.

 

[racerone]

That ring compressor is for 4 stroke engines.------Not to be used on a 2 stroke outboard as the pins in the ring grooves are the issue.----I have made a number of ring compressors like they use in the factory.------They are like a funnel with a taper.-----You line the rings up with the pins and push the piston in with your finger tips.-----If it won't go in try again...-------No hammers required for this type of work.---------Examine the ring grooves with a magnifying glass to see that they are different !

 

[Faztbullet]

I have the same compressor and have built hundreds of motors with it with no problems........

 

[emdsapmgr]

I hand-fit all of my pistons, like racer does. Drop the piston in the hole and push the bottom ring into the groove by hand, all the way around. When the ring compresses enough, the piston will drop, then do the top ring by hand-same way. I do this on all my V4 and V6 blocks. You won't have any issues.

 

[domaotc]

I broke #5 with the screwdriver method, although I blame myself for using too much force. Just to work on my technique, even though they are not the right rings, should I be able to compress the top ring while it is in the bottom groove and have it go into the cylinder? FYI, the pistons slide right in without the rings and actually got one in previously with both rings that I foolishly removed when I thought I had the insertion method down pat.

 

[emdsapmgr]

Using the by-hand method: Once you compress the bottom ring, the piston should slide slightly down in the cylinder. Once you are sure the bottom ring is compressed fully, then compress the top ring till the piston slides down, again. You'll be set.

 

[fhhuber]

Even with the right tools... doing it wrong will break the rings.

I like using a ring compressor tool.
Apply some assembly lube to the rings, piston. tool, and cylinder walls.... grease or even some of the 2-stroke oil. Just not dry.
Squeeze down the rings tight, (wiggling the tool so the rings seat in the grooves and line up with the pins properly) then loosen slightly to where the piston can move with fingertip pressure.
Slide the piston into the cylinder slowly and with gentle fingertip pressure.

If you have to force it, its wrong. Back off and figure out why its not sliding in EASILY

The tool makes it easier... if you do it right.
If you do it wrong then any method will fail.

 

[Chinewalker]

Just out of curiosity, are your rings well fitted to the bore? Just wondering if maybe your trying to use oversize rings in a standard bore, which might bind up.
I use a similar method to the above, substituting a pair of popsicle sticks for a screwdriver. I gently compress the ring with the sticks pushing in from opposite sides, then work it, gently, until the piston slides in. Never broken one...

 

[flyingscott]

What kind of rings are you using are they the same manufacturer sometimes mis-matched rings and pistons do not fit well together.

 

[domaotc]

FYI, the rings I purchased were the right size OMC rings. I also managed to break the rings that were on the pistons originally. So is it a yes or a no for the top ring fitting in the bottom groove? Again I wouldn't be trying to run the engine with the wrong ring just trying to get the insertion method down

 

[AlTn]

youtube vid. "Small girl rebuilds small outboard engine" parts 1 and 2 will really help you to watch....11 or 12 minutes in length

 

[racerone]

There are a number of folks saying that they have assembled these motors without breaking any rings.--Examine the rings and grooves carefully to see that they are different.---And no I would never assemble a motor like this with that tapered ring in the bottom groove.

 

[flyingscott]

Are the ring grooves clean take an old ring and clean the groove. Also to make sure your rings grooves are clean. Take your thumb and forefinger and put it around the ring and squeeze it closed. The ring should compress to be flush or almost flush with the piston.

 

[F_R]

It baffles me why you cannot see the difference between the upper and lower ring, and their grooves. You shouldn't even have to ask that question. Or are we missing something here?

 

[thumbnut]

My wiseco's use different rings from oem and are interchangeable. Maybe one has wiseco's..only thing I can think of...