It is safe for plastic gears.
Steve
Originally posted from steam rules:
I contacted pennzoil recently about petroleum vs synthetic oils in my equipment - mixing, benefits, problems, etc.
They advised:
petroleum/synthetic oils are compatible (at any mix ratio).
one can follow the other with no major issues (however they pointed out that synthetic following petroleum will ultimately flush all petroleum out, at full strength).
for a scientific reason I don't readily recall, synthetic gets into spaces of closer tolerances than petroleum, adheres to surfaces better, and reduces friction more effectively than petrolium
synthetic is not destructive to plastic/rubber components.
From the standpoint of cleaning out old oil, good surface adhesion, and compatibility with rubber and plastic; syn oil may be a good choice in some lube applications for model/toy trains where grease is not necessary.
Sounds like I am going to synthetic oil for my railroad's applications. A quart in a needle oiler should last me approx. 146 years.
