The 50/50 blend is just my anecdotal experience with homebrew fuel - no research. But the owner of S&W once came to our club to give a presentation on fuel. I recall that he recommended total oil content of 2% castor and 18% synthetic. He thought this was a good compromise that would work well in most engines and would give the high-temperature benefits of castor. I don't know if it was just his opinion or he had some research to back it up.
I do not have problems with gummed up engines using the 50/50 blend. Some of my engines sit for a year or two without use. And I don't have problems with staining. I don't know why others have different results. Maybe all castors are not the same?
Originally Posted by
Bambook7
JPmacG -
Thanks about the prices of castor and synthetic oil, I thought it was the other way around..
So using castor oil & synthetic oil in the blend let you enjoy benefits of both types, the question is the the proportions of those two in the mix.
I use mainly abc engines (Rossi, mvvs, sc) and for them I use Morgan Omega fuel 5%, which contains 17% oil, from which 30% castor and 70% synthetic.
That gives you 5.1% castor & 11.9% synthetic (out of total).
I add the amount of castor oil (of the quality Klotz Bennol) that gives me 6% of castor in the blend, and all my engines are happy with that for years now.
BUT, after reading this thread, my conclusion is that, first: maybe I use too much oil in my blend, and second: I should swap the proportions of castor & synthetic in my blend, meaning:
Maybe the blend should contain something like: 5% nitro. castor: between 8-10%, synthetic: 6-4% (14% lube on total), 81% methanol.
The thing is: is 4 to 6% of synthetic is enough to prevent the gumming phenomena in the engine?
Or maybe I should say: what's the minimum percentage of synthetic out of the total lube to prevent the gumming phenomena in the engine?
If one knows the answer to this, then no matter the amount of lube one uses in the blend (as long as it's above the engine minimum,off course ) - one just have to keep the right proportion inside lube blend..
So, did someone make some research\experiments about this proportion and have some insights regarding it?
Thanks!