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Rotax 912 Oil Quantiy
- Thread starter JohnF
- Start date
I have found that it takes fewer turns if you stop at TDC on each compression stroke and just let the cyl pressure fully bleed down past the rings.
When the oil is real cold it still take quite a few cylinders but it is at least fewer than if you flip it fast.
Eeeyikes..... Be extremely careful here - a hot engine can fire under just the right circumstances. Much more dangerous, the 912's are shut down like auto engines by killing the ignition, not cutting off the fuel like a traditional a/c engine. so you still have gas in those hot combustion chambers at shutdown which hugely adds to the danger when hot.
Personally, I don't dare go near the prop on my 912 for at least a half hour.
Turning the prop through slowly is the best way to burp the engine and, if you value your life, do it only when the engine is cold!.....
LS
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You're probably ok if you turn it over slowly enough that only a little compression builds up on the compression strokes, but I guess I'm just paranoid. All it takes is some cheap gas and a still-smouldering bit of metal or carbon deposit in a cylinder and it could all be over just like that.....
If the motor is so cold at preflight that it takes forever to burp, it probably shouldn't be started without being preheated anyway. Fortunately, the 912 is a small motor and only takes a couple hours at most to get to a good starting temp (I use a $15 space heater hung on the prop shaft blowing onto the engine with an old down coat over the top of it). For the RV, a preheater is a snap to make with a space heater and some dryer duct...
LS
Scott...how cool...I did that today (same weather) and it only took 30...you cut my turning in half! Thanks for the tip.
attackpilot
Active Member
I am probably over thinking this, but...
Is there any detriment to having all the oil in the oil tank while the aircraft/engine is sitting there for an extended (more than a day) time?
I thought that the oil provided some corrosion prevention between runs. If you burp the engine soon after running, it seems to me there would be little in the engine itself.
Like I said, I am probably over thinking the issue.
Joe Hutchison
P.S. Flew with Mitch Lock while home on R&R and he is a true ambassador to RVs and the RV-12. I was pretty sure I wanted RV-12, but he removed any doubts. Thanks Mitch.
Is there any detriment to having all the oil in the oil tank while the aircraft/engine is sitting there for an extended (more than a day) time?
I thought that the oil provided some corrosion prevention between runs. If you burp the engine soon after running, it seems to me there would be little in the engine itself.
Like I said, I am probably over thinking the issue.
Joe Hutchison
P.S. Flew with Mitch Lock while home on R&R and he is a true ambassador to RVs and the RV-12. I was pretty sure I wanted RV-12, but he removed any doubts. Thanks Mitch.
The engine will still have oil in all the gallies, oil pump, hoses, bearings, etc., it just doesn't have any oil laying in the bottom of the engine case (which doesn't protect any internal parts any way. After the airplane sits for a while, siphon action will drain some oil back into the crank case. That is the reason you need to "burp" the engine to get an accurate oil level measurement in the oil tank.
the_other_dougreeves
Well Known Member
I normally add 3L of the Shell semi-synthetic after oil changes, a few ounces to pre-oil the filter and the rest in the tank. Always seems to come out Ok. Rotax spec is 3L exactly. Too much oil and it will come out the oil tank breather.
As for burping vs not burping, I always look at the oil level first. If it's within the acceptable range, I don't burp the baby. There is some good history on the acceptable oil level and burping in some of the "Power ON" columns that Phil Lockwood wrote for EAA.
TODR
As for burping vs not burping, I always look at the oil level first. If it's within the acceptable range, I don't burp the baby. There is some good history on the acceptable oil level and burping in some of the "Power ON" columns that Phil Lockwood wrote for EAA.
TODR
MartySantic
Well Known Member
Anyone have the link to these articles??
the_other_dougreeves
Well Known Member
It looks like EAA has removed the Sport Pilot magazine articles from their website. You can still get at the articles by googling them. Here is one of the articles that talks about the old and new dipstick.
TODR
vic syracuse
Well Known Member
This burping of the 912 is interesting to me. I have about 1100 hours between 2 912's I owned, and I never burped them once. I always checked the oil level after shutdown to make sure I had the right quantity. Yes, it would be lower than that on the preflight the following week, but unless there was a puddle of oil on the floor or in the cowling, I assumed it was still all in the oil system. I don't like turning props on engines by hand. I still have nightmares over one gone awry many years ago.
As for preflights, I never understood them for airplanes that you own and only you flyand are in a secured location, like your own hangar or home). I always do a thorough postflight and a cursory preflight. I'd rather find something wrong with it on the post flight and have time to go fix it rather than find it on the preflight when I want to go flying.
Vic
As for preflights, I never understood them for airplanes that you own and only you flyand are in a secured location, like your own hangar or home). I always do a thorough postflight and a cursory preflight. I'd rather find something wrong with it on the post flight and have time to go fix it rather than find it on the preflight when I want to go flying.
Vic
Hey Vic
I owed a 912S before. I found that if I had a long slow taxi back to the hanger, oil would build up in the engine more than when operating at normal RPM. I feel it is due to less ring leakage on a hot engine, and was normal. If you burped it, it would come up by as much as a 1/2 qt. ( From below the mark on the stick, to near the top of the mark on the stick ). My experience has also been that they use oil for the first few hours. If you don't burp them, you really don't know what your total oil amount in the system is.
John Bender
I owed a 912S before. I found that if I had a long slow taxi back to the hanger, oil would build up in the engine more than when operating at normal RPM. I feel it is due to less ring leakage on a hot engine, and was normal. If you burped it, it would come up by as much as a 1/2 qt. ( From below the mark on the stick, to near the top of the mark on the stick ). My experience has also been that they use oil for the first few hours. If you don't burp them, you really don't know what your total oil amount in the system is.
John Bender
