My new MVVS came with synthetic break in oil. Is this the best to use? I thought synthetic oils prolonged the break-in period. Also, what size prop & pitch to use for break-in?
Thanks,
Z

Z,


In Europe, there are different synthetic oils available.

The 'break-in' oil allows the engine parts to wear-in.

The 'normal' synthetics are supposed to prevent any wear whatsoever.


Use this break-in oil as directed. Change to dedicated running two-cycle, gas miscible oil after the break-in.

How much test stand time should I run before installing on the plane? I'm running a BCM wraparound muffler, XOAR 24-8 prop.
What sort of rpm should I expect?
Z

Hi!!

I've started my engine (evo58gx2) for the first time this week with a 3w wood prop 24x8 and evolution inverted muffler
at the end of the break-in the rpm was 6800

On the BCM wraparound restricter you will be lucky to get over 6500rpm, in all probability not over 6000rpm, the Evolution muffler is better and a canister exhaust is the only way to use the full potential of these engines.

Mike

I've got the first tank thru it now, and I'm seeing 6000. I haven't touched the needles other than to open them about 1/4 turn from the factory setting, before starting. The muffler has the "scrunched" outlets, so I know I can pick up a little there. Is there anything I can do to keep this thing from running backwards?
Z

Haven't touched the needles? Why is that? The needles are set to run, but nothing else. Let the low needle be rich, and ASAP tune the high needle for good throttle response and non-sagging top end best power. Needle settings are only good for one altitude and/or prop-muffler combo. Factory settings cannot cover all so:::::
You should adjust the carb. Do not run prolonged full throttle, but do let the engine work hard and give it some time to cool in between. Then let it work as hard as possible again, until all is limbered up.
That should take about 10 running hours. (At ~1.5 oz fuel each minute makes 900 oz of fuel or ~6 gallons)

I haven't touched the needles because it starts and transitions good just where it is. I'm not expecting too much until it loosens up a bit.
Only 16 oz thru the engine thus far.
Z

tune the engine like you should, and then run it in a plane. Test stand runs are not the best way to run in an engine.
Running in takes about 10 hours, during wich you have to let the engine work quite hard, quite short, with relaxing running in between, so all parts set well and match to each other under full load conditions.
In the end, the engine will adapt to your personal style.
For carb settings, see http://www.prme.nl/forum/viewtopic.php?t=10

I plan to run another 16 oz or so thru it before putting it in the air. I'll keep you posted on how it goes.
Z

1st run after altering the muffler (BCM wraparound) gave me a 200 rpm increase. Still only getting 6200 with a 24-8 XOAR, so I'm a ways off. Engine often starts backwards. Is this a sign of the ignition being too far advanced? This bugger really nailed me on the thumb while trying to start it. Luckily, I had on a heavy leather work glove, but it still was a heavy whack.
Z

Starting backwards most of the time is due to a very light prop with little flywheel mass.
Check your ignition. It should fire with the piston 0.1mm before top. Insert a screw driver in the plug hole, and find the point where the driver causes a slight resistance before the piston will pass TDC (top dead center) . When the piston just touches the screwdriver, that is where the ignition should fire.
The 58 is not a mean engine. It does need respect though, is very powerful, and and by no means a toy. Electronic ignitions will set the engine off at any speed, so one should be prepared when playing with the prop. Better still, never play with the prop unless you want to start, or the ignition is OFF

I just checked the timing with a degree wheel, and my dial indicator. It falls within the parameters you give. The magnets are 180 degrees apart. I also weighed the 24-8 XOAR @ 136 grams. The only other prop I currently have is a MSC 24-10 that weighs 172 grams. I plan to use a spinner when I start flying later this week, so perhaps this will add to the rotating mass.
Z

Use the 24x10. It fits the engine better.
Also it might help to set idle speed slightly higher. I would suggest 1600 rpm to start with, and then go from there.