Hello all.

I just got a pair of MVVS .49 engines (one counter rotating) for a twin project. For the engine break-in I brought 1 liter of 80/20 fule for each engine. Half of the 20% oil is castor. I also brought 5L of 5% nitro fuel with 10% synthetic oil and 8% castor for flying after the break-in. However, I now read on this forum that the recommended fuel is 10% synthetic + 10% castor. Wouldnt the fuel I got be OK? I don't plan to run the engines leaned out for max performance but rather let them run on the rich side for reliability (normaly I run my engines 300-400 RPM from max but these i will run 500-600 from max).

Does the best fuel for MVVS engines depend on the muffler used? I have 1 each of the standard, silenced and mini pipe to try out after break-in with the standard muffler.

Why does MVVS and the experts on this forum recommend 20% oil (at least half castor) when in my experience other brands of engines such as OS or Enya run fine on 18% synthetic and 5% nitro? Whats the difference between OS and MVVS here?


Regards
RCer.

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.

Thank you for your reply.

I haven't run the engines yet so I can still add more oil to the fuel. The castor oil used in the fuel is Castrol-M oil (castor based oil) and either AeroSynth or MolSyn syntheric oil. Unfortunately I dont have easy access to the fuel brands you mentioned. Its either CoolPower, Magnum or the mix from my hobby pusher which is the one I just listed above. My hobby dealer can mix it any which way I want.

Actually I was of the impression that the need for running castor oil in our engines came from the times before quality synthetic oils where available.

I will try add more castrol M to the mix so I get 25% oil for break-in (15 castor + 10 synthetic) and 10/10 for normal operation. Just a further question: Won't the engines become brown/black and gummed up from the castor?

RCer,


I did no specifically see that you are from Denmark, or I would not have mentioned these brands.

The MVVS .49 hardly spews any fuel droplets from its carburettor, while running, even when adjusted too rich.
So the 'brown engine syndrome' will not be too much of a problem.

Castrol-M is Castor oil, for all practical purposes.

Dar. Thanks for your replies.

I will get some Castrol-M and add to the mix. No reason to take chances or experiment with a twin engine setup. I plan to run with onboard glow for easy starting and for better low speed reliability.

By the way I just took one of the engines apart. Look really nice for the money. The casing finish is a bit rough compared to my OS an Thunder Tiger engines but who cares as long as they work well. The casing on the inside has some small holes in it but that wont matter with the piston sleeve inserted. The sleeve look real nice and the chrome plating look thick. Also the engines look awsome with the blue heads. Again for the money these babies cost I think they are pretty well built and from what I hear they run well too. I look forward to break them in next weekend.

One recommendation. One should disassemble the engine and clean them well with fuel or similar. I found several metal particles in both of mine. I do this with all my new engines and only on my Saito did I find nothing. After cleaning the engines I lubed them well before assembling. As lube I used sewing machine oil (acid free).

Regards
RCer.