I’m running Castrol 20-50, which is a great lubricating oil, but apparently it doesn’t burn real well.

 

Al

I believe that Castrol invented multigrade oils.

 

Mutigrades have long chain polymers (plastics) that link up with temperature increases to change the pour speed of an oil. So 20 weight oil is doctored with additives to make it pour, or, act like a thicker oil at operating temperature. So, the 20 in 20-50 is the base oils actual pour speed or weight. So its 20 weight oil but now not all of it is oil. Some of it is plastic that neither lubricates or burns well. So you get a gummy mess when you burn it, and even when you overheat it in the combustion chamber, and you get stuck apex seals after a long sit still. So, if you can still get an OMP adapter off of Richard Sohn or Tracy, use that and run a multi grade in the sump, or a good synthetic straight weight. And run a good 2 cycle oil in the OMP. No adaptors available?

 

Drill into the front cover at the lateral oil gallery to the OMP. Weld on a dash 4 male. Drill into the gallery next to the new fitting and TIG the gallery closed to engine oil. Connect a dash 4 line to the new fitting and run it to a bottle of 2 cycle oil on the fire wall.  

 

Clean burning oil and a clean engine and prop.

 

A name brand synthetic straight weight in the sump should be 30 weight up to 220 degrees.

Then 40 weight up to 240 degrees. Another advantage of a full synthetic is it has much less drag than dyno oil for any weight. It moves easy when cold and can be run colder than a dyno oil of the same weight. Over heated synthetics are still oil when they cool off. Multi grade dyno oil becomes black snot.

 

Premixing 2 cycle oil into the fuel is the best for brutal engine use, but is a pain in the rear.

 

Nobody goes over 10,000 RPM on dyno oil.

 

Lynn E. Hanover