Oil that is flammable at high temperatures forms up into combustion products and glue and gum to stick side seals.
So, use an oil that is still oil and nonflammable at high temperatures. Like a synthetic 2 cycle oil. I used to find free engines outside my shop. No starts because of no compression because of stuck side seals.
Combustion products are not supposed to get past the side seals. Nor past the corner seals. Nor past the end of the side seals from too much wear. So, the side seal is a combustion gas seal and an oil scraper.
So any oil that gets past the side seals will be gathered up by the big round oil scrapers at the center of the rotor. Then pumped into the sump, adding to the sump oil.
On your next (or first) engine rebuild, Some tips:
Use new seals everywhere. Use new seal springs everywhere. Make a jig to grind the tips of side seals to fit the corner seals perfectly. I cut the side out of a junk rotor so I can hold onto the seal. Reduce a grind stone to just fit into the corner seal hole in the rotor. The stone can be mounted in a drill press. The stone will replicate the corner seal shape. Use a broken side seal sharpened on one end to clean out the side seal grooves of your used rotor. Use only solid corner seals (not the ones with the rubber plug. Much stronger.
I fit the side seals to zero clearance against the new corner seals. After you get close, do the end shape deal.
Then break the ground ends edges) to .001"
With new springs everywhere I fit the side seals tight enough that pushing two seals and a corner seal down, the three will spring back up without trouble. Then test the assembled seal package with a piece of Plexiglass to be sure they all pop back up after compression. All of the books say an actual distance measurement for this fitment. However, as soon as the engine starts the end of the side seal begins to wear a groove into the corner seal. Note that each corner seal pushes one side seal around the circle. So not much wear on one end of the side seal. Wear occurs on both ends during compression and combustion. One set of side seals will last through 2 rebuilds with this system. You can turn up 9,500 RPM after a 2 hour break in run at 2,000 RPM. More if you are unsure of your skills.
Note that the oil scrapers have springs that are handed. Each spring can only be used on the front of a rotor or the back (Flywheel end) depending on the end of each spring with the round tip. Done right that spring keeps the seal from rotating backwards as the engine runs. If installed on the wrong side, the spring will not develop enough pressure and will let the seal walk backwards and wear through the spring and start dropping chunks of spring in the groove.
Lynn E. Hanover
In a message dated 5/13/2019 11:45:02 AM Eastern Standard Time, flyrotary@lancaironline.net writes: