Chris_Crawford

I've been reading the other thread on getting the optimal performance out of a norvel engine, and I have a couple more questions for anyone who can help.

When breaking in the engine, should the throttle be fully opened, full closed, or somewhere in the middle?

If I start with the needle valve at about 2 1/2 turns open, is closing the valve making the engine run more rich or lean?

What is the purpose of the small screw just aft the needle valve, and how should I go about adjusting it?

The muffler that came with my engine is connected by a little bent wire that goes around the engine and holds it in place. However, it does not hold it too tightly, and the muffler does not stay exactly over the exhaust. Is there something I should do about this, or do I even need the muffler?

And finally, I've read about the importance of having a pressurized fuel tank, and from what I read, I understand that to mean that the engine runs best when air is being forced into the tank, which in turn forces the gas into the engine. However, I've noticed that my engine runs best when I have the vent line on the fuel tank plugged up allowing no air to go into the tank. (This seems to work better than running the exhaust line to the top of the muffler.) What is going on here, and is that bad for my engine?

Thanks in advance for any help you can give.

-chris

Lynn S

I just bought my first Norvel. It is a .074 Big Mig. I have oiled the cylinder(with the head off) and will let it set (cure) for 24 hrs, then turn it by hand with the head off for 100 turns or more.
The screw you are talking about is the Throttle Lever Stop Screw, this is to adjust the range of movement of the throttle arm. this is item #20 on my instruction sheet. I would run full throttle at first then vary the speed after a few runs.It will need to run rich the first few runs. You adjust fuel mixture my turning the needle in clockwise to be more lean and out counterclockwise to be richer.
You need to connect the fuel tank vent line to your muffler and the other line to the carb. I don't see how it could run with no vent at all or just one line to the carb and no vent, air has to enter the tank to replace fuel drawn out.
I like the looks of this engine.
I look forward to giving my Simple Extra more power.

Edit: I just turned the engine over by hand after giving the motor oil 24 hrs to cure the cylinder. This was very easy to do, just a little tight at the top of the stroke, but that got easier after the 100 or so turns. I must have turned it over 300-400 times.
I'm ready to fire this baby up as soon as I get it mounted on the plane!

nitro joe

My Feedback: (2)

The break in debate continues...
(Not necessarily Norvel applicable)



http://www.rcuniverse.com/showthread...59&forumid=145]

Bipe Flyer

Clockwise is leaner, counter-clockwise is richer.

The small screw is the throttle stop. That's the first thing I throw out, the second being the sreen on the carb.

The spring sucks doesn't it? Later models seat better. I've run some and just let the muffler leak with no adverse effects, on others I've made a gasket with high temp RTV.

The reason plugging the vent line "seems" to run better is because you have the engine set rich and plugging the vent line leans it, producing more power... but not for long. The engine will go lean and quit if you do this. The fuel in the tank has to be replaced with air. Use the pressure. In the air it will make for a more consistent running engine.

annoyer

could you look at my post annoyer, Guillows plane, rc

putt_13

My Feedback: (3)

I cant wait to get into 1/2A. These airplanes seem like a blast. How long should i break in my .061. Do I just run some fuel threw it. Also, I have some common household oil, like for sewing machines, etc. Could I use this to oil the piston?? THanx -Patrick

Lynn S

The information sheet said use a few drops of castor oil or high quality machine oil, 3 in 1 oil is too thin. or lighweight motor oil.

putt_13

My Feedback: (3)

I plan on using Air Compressor Oil. I was talking to some guys at a club, and he said that after each run, he puts a little Air Compressor oil into the clyinder, and let it sit until they fly it again. Will this cause any harm. -Patrick

Bipe Flyer

I don't use after-run oil unless I wont be running the engine for a few months.

putt_13

My Feedback: (3)

When I do the break-in, like turning the prop over by hand 100+ times, can I just use like a lawnmower/chainsaw oil. I will see what its specs are, and post them later. THanx -Patrick

Japanman

I wouldn`t recommend it. Firstly chainsaw oil etc is mineral based. mineral oils have a very much lower ability to prevent scuffing than synthetic and castor oil. Castor oil has the very best anti scuffing properties of any oil redily available.

Secondly- norvel engines have a coated aluminium cylinder that has a very high thermal expansion co-efficient- e.g it gets a lot bigger when it warms up. If you turn it over by hand cold, you will wear the piston down so that it fits the cylinder cold. since your engine will be HOT when its running, this is how you want to run it in. Some guys reccomend heating the cylinder with a heat gune before you run it for the first few times.

My advice is- don`t run it in too rich- run it slightly rich, and NEVER LET IT SAG- this will cause more damage than any other thing.
other than that its not rocket science.

Have fun
Japan Man

putt_13

My Feedback: (3)

Ok,
What does SAG mean. I know it cant mean like the metal melts and begins to droop down, so what does SAG mean. Thanx -Patrick

Japanman

It is a term used to describe when the engine over heats and goes lean, or vice versa. its really bad for the engine because some parts, e.g the piston and liner get much hotter than they should be- this makes them bigger than normal which can cause them to wear much faster- also with the added heat the oil goes thinner and loses much of it`s ability to stop wear-

so keep the engine running SLIGHTLY richer than its peak power setting- its a good idea to pinch the fuel line every 20 seconds or so to check it is still very slightly rich- if it is it will speed up a little- if it dosen`t , it is too lean. it also is a good thing to do this as you run the engine in as it keeps the teparatures from getting too cold- what you are trying to do is run the engine at its probable normal running temperature - but when new the added friction of all the new surfaces makes it run a bit hotter- hence the slightly rich setting to keep it at normal temperature.
I know all this sounds a bit technical- but i think it pays to know what you are shooting for.

J.M