RCer,


The manufacturer of MVVS engines dictates the use of 20% Castor oil and 80% methanol and for very long, the use of nitro was forbidden and would void the warranty, as would using synthetic oil.

But they have grown and adapted the engines to use some synthetic oil, and some nitro (5%).
But you would still void the warranty if you use any less than 20% oil, at least half of which is Castor.

In the older, larger glow engines; 26 and 35 cc (1.60 and 2.15), which had the needle bearing con-rod, if you used any less than 10-15% ALL Castor, you would eventually damage the con-rod, the crank-pin and the wrist-pin.

Repair is VERY costly, if this happens.

But it is not only damage and warranty issues.
From my own experience, in the up-to-.91 MVVS engines, using less oil will, in the short run, make the engine run lousy... Harder starting, bad response and low reliability.

I tried it personally on my testbed .49, with Model Technics Duraglow 5% fuel, which contains 6% Castor and 9% EDL synthetic oils.
Added 5% Klotz BeNOL Castor oil and the engine returned to its well mannered self again immediately.
Customers with other MVVS engines, especially .91s, saw any and all sorts of maladies go away, with the introduction of 20% oil, at least half of which is Castor.

Fuels that 'fit the bill' are Sig Champion, PowerMaster GMA and some others too.

Some other engines that can manage and run well on fuel with less oil, or less, or no Castor oil, don't last as long as MVVS engines do.

So I guess you would have to live with the MVVS fuel needs. It is not that hard to do.
I recommend using 25% oil for break-in, BTW.

Read [link=http://www.rcuniverse.com/forum/Tapered%2DBore_Engine_Break%2Din_%2D_Upgraded/m_1850473/tm.htm]this thread[/link], please, for your next engines.