piston rings

[boso]

Hi guys,<br />I have the Evinrude Fastwin 18hp outboard from 1967. I decided to replace all the parts that need to be changed and make my motor like a new one. My question for you is when I put only the ring (without the piston) in the cylinder, what would be the max. gap between the ends of the ring before I have to change it? <br /><br />Thanks!

 

[lark2004]

Re: piston rings

replace the rings. DO NOT attempt to re-use the old rings.

 

[Paul Moir]

Re: piston rings

The piston ring end gap spec is .007" min and .017" maximum (0.18mm min, 0.43mm max). Don't forget to check this gap in a few places in the bore. But like Lark says, you're going to want to change them for a fresh set.<br />Finding a new set of rings outside the USA will probably be pretty difficult. Here's a couple sources for NOS (New, Old Stock) rings in the USA:<br />Twin City Outboards<br />PartsforOutboards <br />Laing's Outboards<br /> <br />Good luck!

 

[Dhadley]

Re: piston rings

With todays ring material and fuel (combustion heat) we dont really go by those old specs anymore. Most gaps are anywhere from .012 to .022 depending on whose ring it is. One particular set of OMC rings had a gap of .026 - .034.

 

[boso]

Re: piston rings

I have to change to many parts and I don´t want to spend to much because the motor isn´t in good condiction. <br />I will check the gap but I think it is around .020" <br />Thanks for your replies!