Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Hi David,...some non-critical issues to consider but just isn't conventionally executed. This "Novel"  Flourogel rubber o-ringed engine Lubrication arrangements are seemingly unaddressed by manufacturer, not mentioned on instruction sheet & left up to owners option. While the o-ring probably needs far less thinner weight oil than a conventional metal o-ring,  the as manufactuted straight shaped  piston skirt & cylinder wall  texturedless surfaces (no apparrent oil lubricant retaining  piston skirt micro grooves or cylinder wall crosshatch) would require a continuous, heavier viscosity
 Lubricant to avoid eventual  frictional scoffing damage & present conflicting type manually applied lubricants. The long piston itself requires no direct friction generating  to cylinder wall contact & and an additional piston near bottom end ring groove & similar rubber o-ring would let the piston almost frictionally "float" being physically isolated from the cylinder wall. A  Dry, rubber o-ring compatible, ptfe telflon long lasting dry lubricant applied to the cylinder wall would greatly reduce manually applied lubricants & further reduce non-desirable, upper cylinder soot generating "wet" sparkplug exhausting fuel mixed lube concoctions as the piston's upper & lower rubber o-ring lube requirements would be completely addressed by the lowest measured, friction coefficient, dry ptfe telflon cylinder wall coating. Commercially made, Dry ptfe diy lube are readily available. This cleaner running, non-fuel lube mix, lowest friction, dry lube approach came about with your mention of adding a lower piston ring groove & could optimally address the M-90's unique rubber o-ring/ metal on metal piston to cylinder wall friction scuffing  lubricant needs finally eliminate the messy oily spitting exhaust issue..tom.