Originally Posted by
757jonp
If the gas fired Saito radials can run on 15:1 (6.2%) oil, the alcohol version will get a lot more oil at 10:1. (9%) Especially considering 40% more fuel by A/F ratio. 9% /6.2% x 1.4 = twice the lube available.
Telemaster... percentage vs volume when talking about mixing oil and fuel always gets me confused, and probably 90% of the folks on here too! Right off the back of a quart of Klotz kl-200 oil they (Klotz) recommend 15-20% oil for two and four stroke glow and 5-10% for 4 stroke ignition (gas or methanol fuel unspecified). I couldn't find any specific information of how gasoline vs methanol fuels effect an lubricants ability to perform it's intended purpose. I suspect gasoline has superior lubricity than methanol, therefore less oil is needed?? I have no idea why adding an ignition system would allow you to get away or require less oil less oil....
One thing is for sure. If you don't have enough oil getting to where that engine wants it you'll know about it in shortly!
Fuel is mixed by a percentage of volume.
It boggles my mind that some can equate gasoline having more lubricity than the 40% higher (by volume) lube content going trough the engine running on methanol, even when the % of lube (by volume) is the same for the gasoline as well as the alcohol mix.
I think the high lube content for even GI (glow ignition) is a trow back from ringless, lapped pistons/bores.
There is a poster that frequents the ASP 400R5 thread that works for Laser Engines R&D. He has successfully run GI Laser 4-strokes on lube percentages much much lower than the conventional wisdom dictates with no ill affects.
Introduce CDI with stable ignition timing and the lube requirements should be even less critical.