Not24

My Feedback: (1)

I recently had to install a new cylinder liner and ring in my engine. Even after a gallon on the ground and another half gallon or so in the air, I still think the compression is low. I'm running 5% cool power and a 16-4W prop. I originally used a 15-6 and had more compression and power than I do now after the new parts. Do I need to go back to a smaller prop for break in? Shouldn't a good smoke trail be rich enough for break in while flying? I've got a vp 30 pump on it now to prevent burning up another cylinder. Should I run it sloppy rich to help seat the ring? I didn't have to do anything special when the engine was new, and that's why I am confused. My engine should make a few more rpm's than it does, and it should flip start easily, like it used to. Now I need my electric starter to spin it fast enough to fire. Any help is appreciated.

w8ye

My Feedback: (16)

There's something wrong with your ring seating?

Did you use fuel with a little castor in it?

On your ring, you may have chipped the corners of the gap when you put it in?

Flyboy Dave

My Feedback: (21)

I would guess your ring is slightly out of round, and not seating properly. If
everything was perfect, you would have ample compression with just the
oil you used to assemble the engine....the engine not even having been run.

You will never get the power out of that engine with that fuel, and that prop.
Ringed engines like a fuel containing castor.

FBD.

Cyclic Hardover

My Feedback: (3)

I am going along with the fuel and the prop on this one. I have two of these. With a 16/4. My first clue is your doing 3d with this thing. Anybody using 4 inch pitch wants to hang from it and you have a bad combination of engine/plane, prop, fuel and the rest of it.

Tell us what tpe and size plane your using, may help

Not24

My Feedback: (1)

Used to be on a Funtana 90, but I went back to my flying wing design because it's a pound lighter, and the engine is out in the open. You guys suggesting that a ringed engine is no good for 3D? By the way, nothing was damaged at assy. Cool power has 18% synthetic lubricant, and it has always worked in the past. What is the most sure fire way to seat this ring properly? If it means running 4 gallons thru it on the ground, so be it. I would guess that richenning the pump and flying it would be best. That way the engine would be getting cooled better than on the ground. Also, even though it would cost me power, going back to the stock muffler may help with break in. Here's a pic of my plane.

Cyclic Hardover

My Feedback: (3)

Thats a nice looking plane

Mettler1

My question would be are you getting enough fuel to the engine with the pump and fuel setup? You should be able to open the needle valve and run it smoking rich. If you can't do this you've got problems. Fix this first!

Evil Homer

Can you pull it apart and make the ring did not get damaged during assembly, seems strange that after that much fuel the ring is not bedding in considering the liner was replaced at the same time.

Flyer95

My Feedback: (1)

Not 24,
My experience with ringed Supertigers tells me it will take many hours for this type of engines to be 100% broken in. Just fly it rich and it will get better with each gallon through it. However, can you give us some rpm numbers then maybe someone could tell you if you are low on power or not? What muffler are you using? A smaller prop like 14x6 or 15x6 would also give you better and faster throttle response, more power and good behavior since the engine is new. Good luck, Amir

Not24

My Feedback: (1)

Yes, I can get it to quit it runs so rich. The pump really helped out in the mid range. I don't have a tach, but the one time I did tach it I saw right around 9k on the 16-4w. I'm going back to the 15-6 and I'll richen up the mid range some more. I can't go too rich because it loads up at idle. The model I have it on doesn't need all the power it has, but it does make it more fun. It will take off and fly on three clicks of throttle. It only needs about 10 mph to fly. The cool thing about that plane is that you can fly it in the wind if you want to. The airfoil is 5 inches thick, and top speed is similar to a 46 powered trainer. You won't find one of these anywhere, because this is the only one ever built.

Flyer95

My Feedback: (1)

9k on a 16x4W sounds good to me. Running it slightly rich is the way to go, running it too rich may give you deadsticks or too much hesitation when you need that instant power and thats not fun[].

Not24

My Feedback: (1)

I richened the pump quite a bit and still have good idle and transition. There's a nice smoke trail in flight. I have tried several props, from a MA 14-6 to 16-6 with the 15-6 and the 15-8 being the best compromise. There's not much difference in the 15-6 and the 15-8 as far as performance goes, but the 6 tends to turn up a little better. Guess I'll just keep on flying it to see if performance improves over time. Thanks for your inputs.

EYB