Thedude Posted January 5 Report Posted January 5 I was under my 79 m20J the other day and noticed some white powder residue trailing from the exhaust down the belly. Any idea what this means? Is a cylinder burning oil or something?
redbaron1982 Posted January 5 Report Posted January 5 I'm sure oil wouldn't leave a white powder behind. The only thing I can think of that is grayish is lead. 1
Thedude Posted January 5 Author Report Posted January 5 27 minutes ago, redbaron1982 said: I'm sure oil wouldn't leave a white powder behind. The only thing I can think of that is grayish is lead. So I shouldn't taste test is what you're saying... But is this normal then? I'm assuming there isn't extra lead in the fuel here beyond what's normal 1
redbaron1982 Posted January 5 Report Posted January 5 I don't know if it is normal, my J (and I guess most airplanes) have a white (or kind of white) belly so it is hard to see any deposit. I do know that a graying deposit in the tail pipe is normal. From your pics it looks like there is toooo much white. Did you try cleaning it up and see how long it takes to build up again?
Thedude Posted January 5 Author Report Posted January 5 No I just noticed this before going out of town so I haven't had a chance to monitor it's build up.
N201MKTurbo Posted January 5 Report Posted January 5 I believe it is lead bromide. I wouldn’t put it in your mouth. 2
Rick Junkin Posted January 5 Report Posted January 5 8 minutes ago, Danb said: You run lop ^^This^^ @Thedude Do you run LOP? If so, this is to be expected. It cleans off pretty easily with any good spray cleaner, just be sure to wear gloves.
Thedude Posted January 5 Author Report Posted January 5 Ya I run ROP, ok thanks for the insight, glad to know it's normal and to stop touching it
Shadrach Posted January 5 Report Posted January 5 2 hours ago, Thedude said: Ya I run ROP, ok thanks for the insight, glad to know it's normal and to stop touching it Totally normal. You will get lead on the belly regardless of whether you run ROP or LOP. It just appears more prevalent on planes that are run at peak or LOP because there is very little visible particulate in the exhaust at those settings other than lead bromide. 1
Nico1 Posted January 5 Report Posted January 5 It comes off easily with Buddah Belly, just let it soak a little. Any degreaser probably works well too. 1
Shadrach Posted January 5 Report Posted January 5 3 minutes ago, Nico1 said: It comes off easily with Buddah Belly, just let it soak a little. Any degreaser probably works well too. Mineral spirits are very effective, especially with a spray wand.
Jim F Posted January 5 Report Posted January 5 4 hours ago, N201MKTurbo said: I believe it is lead bromide. I wouldn’t put it in your mouth. I think that's lead too
Hank Posted January 5 Report Posted January 5 I use Aero Cosmetics Wash n Wax; Blue (regular) for the whole plane, except Red (degreaser) for the belly. At annual, I lean my one piece belly against the wall and do it one half at a time.
toto Posted January 6 Report Posted January 6 1 hour ago, Hank said: I use Aero Cosmetics Wash n Wax; Blue (regular) for the whole plane, except Red (degreaser) for the belly. +1 for Wash Wax ALL Blue for everything except the belly, red for the belly
Hank Posted January 6 Report Posted January 6 5 minutes ago, toto said: +1 for Wash Wax ALL Blue for everything except the belly, red for the belly Wipe it on, wipe it off. Even makes cleaning the belly easy. 1
Jackk Posted January 6 Report Posted January 6 Non pumice GoJo also works well for the belly, wipe it on, let it sit for a bit, wipe off. It’s also pretty safe chemical wise Typically I don’t lean my planes out enough to get the white though 1
takair Posted January 6 Report Posted January 6 Is that a crack at the end of the tunnel? Missing screw as well. You might find some CO getting by there….not that much would get into the cabin, but might still be worth a closer look. Also, do you have picture of your exhaust stack? Might be sitting a little high…
Thedude Posted January 6 Author Report Posted January 6 1 hour ago, takair said: Is that a crack at the end of the tunnel? Missing screw as well. You might find some CO getting by there….not that much would get into the cabin, but might still be worth a closer look. Also, do you have picture of your exhaust stack? Might be sitting a little high… Sure looks like a crack as I look back through my photos, I'll be able to check when I get home in a couple of days -- I have a co sensor that hasn't ever shown any issue (reads 0 in flight). I noticed the missing screw too, anyone know what style and size they are? What does exhaust stack refer to? The muffler and everything under the cowling?
takair Posted January 6 Report Posted January 6 By exhaust stack I mean the outlet of the muffler that comes out of the cowl just ahead of this.
skykrawler Posted January 6 Report Posted January 6 The screw is typically a #8 type A sheet metal. Often a stainless steel truss head is used. https://www.aircraftspruce.com/catalog/hapages/tha.php?clickkey=11590 The accumulation is a function of how much fuel you burn and because the tail pipe does not extend out very far. Some of the worst Mooni are M20m LTS with the six cylinders. Pipe Dakota (Lycoming O-540) also get leaded up bad - the triple tailpipes a fairly short. It should be cleaned up regularly. Pretty sure the lead will cause corrosion on the various panels back there. 1
Thedude Posted January 6 Author Report Posted January 6 4 hours ago, takair said: By exhaust stack I mean the outlet of the muffler that comes out of the cowl just ahead of this. Gotcha, this is the best photo I have at the moment.
Yetti Posted January 6 Report Posted January 6 Lead - Goop hand cleaner and some blue roll of towels. - probably goes all the way to the tail.
Thedude Posted January 6 Author Report Posted January 6 11 minutes ago, Yetti said: Lead - Goop hand cleaner and some blue roll of towels. - probably goes all the way to the tail. I just ordered some wash wax all (blue and red) and I've been hoarding blue rolls of towels since I found them at Costco for no reason other than forgetting I already have some at home already, so I think I've got the required equipment, need to wipe down the whole plane
TaildraggerPilot Posted January 6 Report Posted January 6 “Blue” paper shop towels will scratch paint pretty easily. I’d stick with terry cloth with your aviation-grade cleaner of choice.
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