would like to get a few opinions on this. from my research it's obvious there's no clear answer
Engine in question = asp61fs.
The one page instruction that comes with it says 'any good commercial glow fuels (preferable with 10% nitro) should be suitable'. well thats easy. but no particular mention of using this for running in.
The downloadable instructions for the Magnum XL61RFS (same engine but much more detailed instructions) says, use power master 10% 2stroke blend. then later says -"use a fuel that contains no more than 10% nitromethane and no less than 20% castor oil lubricant. synthetic lubricant fuels should not be used during the break in prodeure."
A wee visit to a couple local hobby stores for opinions on break in, and both said 'we use and recommend fully synthetic oil/fuel'. hmmm. they didn't sell castor by itself and came across as saying that using castor is 'old hat'. contrasting!
I know you don't use full synthetic oil to run in a real car engine. but then, the honed surface finish is much more coarse with different loads involved where a low grade mineral oil allows the rings to bed in whereas automobile synthetics are so good that bores can be glazed and never actually wear in. But are we adapting the same theory on a model engine??
Castor is an excellent naturally occuring lubricant that contains esters. It is the esters that has been synthetized in synthetics. the main advantage of caster is it's ability to lubricate at higher temperatures due to it's thermally unstable properties where the oils polymerize to create heavier oils and continue to lubricate if an engine is leaned out and overheated. compared to synthetics which has a lower flash point and will burn off in a hot engine. The downside of caster is it has more impurities, it can create carbon build up and over time gets gummed up with varnish. (polymerised castor oil).
but in terms of 'lubricity', is there really any noticeable difference between them that it would affect the run-in of an engine?
Is there any noticeable disadvantage (not theoretical) to running in a model engine on synthetic oil? Or is it the impurities or other properties in castor that help an engine break in?
I ask this because i can't just go to my local hobby shop and buy 80/20 meth castor fuel.