Blow by and compression

[W.J.Langholz]

I am now running my engine again and have 6 hrs on it. I have no leaks and no dripping from the breather. The breather slopes upward from the front to the rear where it drops out the back. It seems to have more power since I replaced the broken intake elbow on #1. My carbon monxide detector shows 50% less reading since I have new exhaust gaskets. Not sure why or where it was leaking?

John

John

Can you post a picture of your CO detector and what kind it is.

W.

[Bruce Fenstermacher]

Bruce,
If you switched to synthetic (like Exon Elite) you would save more per quart you did not burn!!

That's a good idea John. I'd get right on that and start the larger savings BUT FIRST I need to confirm with W what brand of oil is in that barrel he's got for me at the end of hos runway. Wouldn't want to be swapping between brands willy nilly.

[N2255D]

Bruce,
If you switched to synthetic (like Exon Elite) you would save more per quart you did not burn!!

That's a good idea John. I'd get right on that and start the larger savings BUT FIRST I need to confirm with W what brand of oil is in that barrel he's got for me at the end of hos runway. Wouldn't want to be swapping between brands willy nilly.

Bruce, Just make sure you put some MMO in it and you'll be good to go

[Bruce Fenstermacher]

WEEELLLL. Went flying Sunday and actually remembered to take a plastic bag for over the vent tube. Used some duct tape and taped it on being careful not to block the little vent hole in the side of the tube.

Checked the oil and it seemed to be at about 5-1/2 quarts. Lower than I like and I would have added a quart but didn't have any. So off we went for about a 40 minute flight. Landed for breakfast and quickly exited the plane to see if the bag was still there and it was. And we watched and waited and waited and looked real close but no matter how close we couldn't see one damn drop of oil. Yes there was water but NO OIL.

Well we figured by the time we came back from breakfast there would be some oil but NO.

Left the bag on and hoped it would stay for the trip back. Back home we landed at what is now 1.4 hours total running time. We quickly jumped out so look at the bag which was still there. We watched and waited but there NEVER WAS ANY OIL.

1025091330.jpg

Here is the bag with water and no oil. BTW that is the exact position it flew in, or more likely flapping in the air.

So much for blow by. What does this tell us. It either means that about 5 quarts of oil is the magic number that this engine will not blow over board. Or my vent tube is in a position that the oil is being sucked out of the engine. The palstic bag prevented that.

The tube is not any place weird and is not to long hanging into the slip stream. I'm going to have to put an extension on it and move it see it that changes anything but first I'm going to add oil and see if the low level has anything to do with it.

It is entirely possible that the table spoon and more of oil I'm seeing leaking is just residual oil from inside the vent tube that drains out in a three point attitude but drains back into the engine at level flight.

If indeed I'm not blowing the oil out then it is burning it. Though my plugs do show some sign of oil burning I don't have to pull and clean them at unusual short intervals. My exhaust is pretty white/brown and I'd think that it would be more black and sooty if indeed I'm burning a quart about every 3-4 hours.

1025091322.jpg

[GAHorn]

The breather tube does not "suck" oil out, (there is no "suction" because of the vent-cut/hole above the exit)... nor does the bag prevent oil from flowing out the tube should oil normally do that (again, because of the vent-cut/hole.) The point of my recommending this test was to prove that in addition to discovering if any crankcase-pressure was pumping any oil.
Did you check your oil-level after the flight?

[Bruce Fenstermacher]

Yes I did check the oil and I lost as much as a 1/2 quart of oil or so it seems. I'll check again after it all drains back down.

I know the vent doesn't suck normally but it would if the end was in a low pressure area or acting like a venturi in the slip stream...at least I'd think so You would think the cut hole would stop this but who nows at this point. I just flew my plane and probably for the first time since I've owned it over the last 10 years, it didn't leak or drip any oil. Of course it took a baggy hanging out of the bottom of the cowl to do it so I don't know what to think.

Of course the baggy does add a a few points for the Rat Plane category. Got to do something to make up for a dry cowl.

[GAHorn]

...Of course the baggy does add a a few points for the Rat Plane category. Got to do something to make up for a dry cowl.

Maybe YOU should use a brown-paper-bag....just for effect!

[johneeb]

Have you checked the battery box for the missing oil

[W.J.Langholz]

Hey Bruce

A diaper.....that would go a long ways to the "RAT" plane catagory

thanks for the report, I haven't had a chance to do the bag thing yet

W.

[GAHorn]

Have you checked the battery box for the missing oil

Now, John....I'm especially curious about that comment. Have you ever found oil in your battery box? (I have!)

[wingnut]

...Of course the baggy does add a a few points for the Rat Plane category. Got to do something to make up for a dry cowl.

Maybe YOU should use a brown-paper-bag....just for effect!

Yeh George, especially if was one of those "Armadillo" bags you get your cold beer to go down there in Texas. Here in Arkansas we would use a Pork-N-bean can attached with balin wire.

[johneeb]

Have you checked the battery box for the missing oil

Now, John....I'm especially curious about that comment. Have you ever found oil in your battery box? (I have!)

Nah George I just thought I would suggest one of the last places one would look. How did you come to have oil in your battery box?

[GAHorn]

I haven't got a clue how it got there. I was removing the battery for a 100-hr inspection and noticed a puddle of something in the bottom corner that failed to drain out the centrally-located drain hole in the 3-point attitude. Took a paper-towel to wipe it and attempt to discover what it was and discovered it was motor-oil. Go figure. Maybe stray air-currents in the cowling blew it up under the lid before I cured a leak?

[alaskan99669]

Bruce,

Is there a way you can attach something small at the exhaust pipe exit's to see what accumulates there? The reason I ask is that my plane too uses about 1 qt. per 4 hours and I know it is going out the exhaust because I find it on my flying wires when on floats. The plugs always look fine during annual. My oil turns dark within 10 hours of oil change, but compression tests are good.

[Bruce Fenstermacher]

That woould be a bit hard Corey. What does the inside of your exhaust pip look like. Mine is a white/brown. Is yours black?