Model Engine Company of America
How do install a piston ring - Step by Step
If you are installing a used cylinder it must be prepared properly, click and read this.

Most rings in schnuerle ported engines have a locating pin to keep the end gap of the ring from getting caught in the ports. The ring is usually notched and this notch must line up with the small locating pin in the ring groove.
Place one end of the ring slightly in the groove near the locating pin in the groove.
Carefully walk the ring around the groove.
By walking the ring around the top of the piston you do not have to expand it any more than necessary,
The ring will finally jut pop into the groove, The ring must fit the groove with only a slight clearance to allow free movement of the ring in the groove.
Mark the location of the locating pin in the ring groove. This makes it easier to line up during assembly.
Install the piston/rod assembly into the crankcase.
Push the lower end of the connecting rod onto the crank pin.

This is the important part. You must not allow the end gap of the ring to fall into any of the porting or cutouts on the cylinder sleeve.

 

Start by aligning the skirt of the sleeve with the locating pin in the piston groove. Be sure the end gap of the ring is aligned with the pin also.

Many cylinders don't have the cutouts on the skirt so you don't have to worry about this.

Slide the sleeve into the crankcase with the piston at the bottom dead center position. Allow the sleeve to just contact the top of the piston. .
Notice the ports are aligned so the ring end gap will not be in the cutout area of the skirt of the sleeve.

Many cylinders don't have the cutouts on the skirt so you don't have to worry about this
Keeping the piston straight with one finger, gently rotate slightly back and forth and push the sleeve over the piston. The very bottom of the sleeve is tapered so the ring should walk in to the bore.

Be sure the ring is aligned with the locating pin in the groove. If is is not you will break the ring.

As you push the cylinder deeper in to the crankcase be aware of the path the ring end gap takes. You may have you push it in then rotate it and push it in further.
Line you the exhaust ports with the outlet in the crankcase casting.
The above information is provided as a guide. Since MECOA/K&B has no way of determining the ability of the individual using and understanding this information, we assume absolutely NO RESPONSIBILITY for any damage to person or property from the use of this information.
 

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