Johnson rebuild question (Piston Rings)

[oscar boy]

I am rebuilding a 115 Johnson crossflow motor. The Factory repair manual call for the ring end gap to be betweem .019 and .031.<br />I an using Wiseco pistons. The Piston installation instructions said to be sure and set the ring end gaps,but gave no specs. A small loose paper in the box said to set the gap .004 per inch of bore , which for my 3.5" bore would be .014.<br />Which should I go by the OMC istructions or the Wiseco instructions.

 

[R.Johnson]

Re: Johnson rebuild question (Piston Rings)

Just go by the minimum gap figure, do not try to adjust the gap by grinding. Don't forget to lightly chamfer the port's, after boring, or honing.

 

[JB]

Re: Johnson rebuild question (Piston Rings)

Howdy Oscar.<br /><br />Ring end gap is set to allow the rings to increase in length as they get warmed up without binding the ends to each other.<br /><br />Expansion amount varies with the alloy used.<br /><br />I would therefore go with the gap specified by the people who made the rings.<br /><br />Good luck.