Exhaust residue on struts - lead

[txcub]

I have read the thread under the Carbon Cub on this issue but I am seeing spots of what looks like lead residue on the struts after some flights. I have used Rejex as was discussed but this doesn't help. It still takes a lot of scraping with a fingernail to get these spots off. Has anyone ever tried TCP or is this not OK in the O-200? Don't know if this would solve the problem.

[randylervold]

TCP should be fine in any piston engine, can't hurt to try. I can't say that I've ever seen lead all the way down by the cabane vee though, I would think it would be much too cool by that point to be molten.

[rkortge]

I have those spots also and have tried everything to remove them. A fingernail seems to be the only way. Wax , rubbing compound, bug and tar remover, starting fliud, hot water, rejex, nothing seems to even touch the spots. I didnt know what they were but they are all over my struts, and cabane vee. Keep us posted if anything seems to help.
Rich

[Pete D]

Have you tried 100LL? There is a dispenser right there handy (gaskolator drain) I've had good luck with a terry cloth towel and some fuel on a lot of different stains on the gear. Cuts oil & grease nicely. With a performance paint job where the gear parts are painted silver you need to be careful especially as that kind of paint can be delicate.

Pete D.

[txcub]

Have you tried 100LL? There is a dispenser right there handy (gaskolator drain) I've had good luck with a terry cloth towel and some fuel on a lot of different stains on the gear. Cuts oil & grease nicely. With a performance paint job where the gear parts are painted silver you need to be careful especially as that kind of paint can be delicate.

Pete D.

Yes..still no effect and requires a fingernail to scrape it off.
Jon

[RanRan]

TCP should be fine in any piston engine, can't hurt to try. I can't say that I've ever seen lead all the way down by the cabane vee though, I would think it would be much too cool by that point to be molten.

Lead melts at a 622f. Exhaust gases reach 1500f. Molten lead is quite possible at those temperatures. Let's get the lead out of all CC designs. Lead the charge on this.

[RanRan]

OK. Let's take it a step further. If your mixture is correct the lead gets oxidized - oxidized lead is pure white - it's used to make paint. It's a fine powder and people breath that and that's why the EPA (and governments around the world) took it out of the fuels decades ago.

So, if you are finding a lead residue behind the exhaust...it can only mean one thing - you're running way too rich. Which means the ignition cannot possibly burn/oxidize the lead content in your fuel during detonation but it can HEAT the remaining lead compound into nasty specks of molten lead.

As Randy said, it's not normally seen. I believe the above is the reason for when it is seen.

Let me know what you think. One's man's lean is the next man's rich in airplanes and in life.

[RanRan]

It could also be a fouled plug/s. Or a weak spark. A leaking exhaust valve ( which on an O-200 would be my second guess...enough raw fuel being pushed into the exhaust on the compression stroke). Something is not right - it's a warning sign.

I'd do a compression check - you'd know immediately if it was a valve leak.

Here's the problem. There is some play between the value guides and valve stems on the O-200. Now add lateral pressure on the 'push'. The valve starts wearing on a fulcrum. If the 'push' adds wear to the 'south' it simultaneously wears at the 'north' i.e., on the other end of the valve guide. The result is a unseated, leaking valve that doesn't show up when new.

ECI has an eloquent solution for this fairly common problem. They harden the valve guides and have a much tighter tolerance between the guides and stems. AND they rotate the valves a quarter turn with every stroke. (ECI is the group that helped tweak the Carbon Cub engine)

In all this...is it time to freak out? No, Have fun. It's just wear. But hopefully, CC will tweak the O-200 in the future and make it their own.

[Springloaded]

Next time you get residue on your plane try taking original GO JO(white cream) wipe on plane with palm of your hand let set for 5 min just rubb with palm of your hand & finger tips , hose off.It will amaze you how good it works. A guy i bought my plane told me about it, I havent showed any body yet, that doesnt do reguarly.
Chuck

[txcub]

Started using TCP and it seems to have cleared up the issue......we'll see as more time goes on. Jon