Oil Door opening spring

[David Paule]

Originally Posted by seagull

....The area that looks like a crack is something in the photo, look at the third photo down. It is the same side but with the spring in place, no crack.

Good - thanks for checking.

Dave

[seagull]

Originally Posted by alexe

Nice job Walt!

You did a fantastic job building this airplane, I am SO proud to own it.

[Hornet2008]

I’m surprised you didn’t check the oil level during your pre flight.

[seagull]

I check my oil after every flight, it is easier to "burp" and takes less turns of the prop / gearbox when the oil is warm. I have my own hangar so nobody else touches the plane. I check for leaks on the floor before flights.

Where the "open door" issue could be a problem is going to lunch at another airport, leave the door open to allow the engine compartment to cool and being nice to the fiberglass.

You are right a thorough pre-flight would solve the issue but who among us can say they have never missed something on the pre-flight. We have a lot of secondary checks, Dynon lights / announcements, built into our planes. I felt this was a simple way to avoid a future problem.

[HansLab]

Wasn' t the burping ment to prevent oil to stay in the engine (and perhaps under the cylinders, where it could damage the engine when you try to start it), and ment to move the (cold, for unused) oil to the external oil-can?
By not checking the burp before starting you put the life of the engine at stake, I would say.
My opinion though...
Happy landings!!

[NinerBikes]

I try to leave as much hot oil on the cylinder walls as possible after shut down, and burp first thing in the morning when the engine is cold. I think also that the heavy oil film left on the bores when hot helps with compression when the motor is cold, when you burp.

To each is own, ask Rotax for the final answer. The bores are ceramic silica, if I remember correctly, and the tolerances are very tight, piston to bore, clearance wise. One of the reasons why a 912 ULS or IS stops spinning so quickly on shut down.

[seagull]

Originally Posted by HansLab

Wasn' t the burping ment to prevent oil to stay in the engine (and perhaps under the cylinders, where it could damage the engine when you try to start it), and ment to move the (cold, for unused) oil to the external oil-can?
By not checking the burp before starting you put the life of the engine at stake, I would say.
My opinion though...
Happy landings!!

I realize this is a bit off topic and don't want to derail the thread, even though it is mine

I am new to the Rotax and was told burping moved the oil back to the canister to get a more exact reading of the oil level. I used to burp before each flight and never felt a hard cylinder (from oil pooling). I changed because the turns involved before it would burp was excessive in comparison to warm oil. It seemed like unnecessary wear on the gear box and my arm.

Maybe this is better info:
https://www.rotax-owner.com/en/gener...912-uls#p14724

[seagull]

I would like to learn more about burping and how necessary it is or isn’t. If I am checking oil I would not leave the door open. Cooling the cowling is where the door is left open..........the reason behind the spring.

[Paddy]

I used a spring from a mouse trap for my oil door. I think I used one less "wind" when installing it so it wasn't as strong as in the trap.

[Piper J3]

Originally Posted by NinerBikes

I try to leave as much hot oil on the cylinder walls as possible after shut down, and burp first thing in the morning when the engine is cold. I think also that the heavy oil film left on the bores when hot helps with compression when the motor is cold, when you burp.

Actually, the "burb" is not compression, but rather compression leakage past the piston rings, which pressurizes the crankcase and forces the residual oil back to the oil tank.

Two reasons to "burp"...

• Necessary to scavenge residual oil from the engine crankcase in order to get a true oil level reading.
• Verify that hydraulic lock is not present on any of the four cylinders.

The burping sound happens when the last amount of oil leaves the crankcase which is then followed by compressed air release from the cylinder blow-by.