Lead in spark plugs!

[RScott]

TCP does work in my 75HP Continental with no leaning capability in the Stromberg carb. Without TCP, 100LL fouls my plugs in less than 20 hours & it's so bad I have to start it at full throttle--hand propping no less! Needless to say, I use TCP.

BUT, for a homebuilt, you can use Decalin which has the same active ingredient as TCP, but a different and safer carrier. TCP is pretty hazardous & they say not to carry it in the airplane; Decalin no problem. Get it at Aircraft Spruce.

Decalin is working on certification, but no go so far.

If you go for mogas, be sure to check for alcohol. Mogas works great for my plane, but not always easy to get anymore. Kind of like 80 octane.

[IowaRV9Dreamer]

Originally Posted by David Clifford

I have lead build up on the bottom plugs on my 0-235 L2C. I tried the high rpm shutdown method per Lyc, and just recently started adding the TCP fuel additive that is supposed to help. Doesn't look like the additive is doing anything.

I have the same engine... same leading. I think the engine would lead less if the compression ratio was a bit higher... but FAA isn't interested in allowing that...yet.

While I try to convince them, I have had good luck (80 hours since servicing plugs no problems yet) with super agressive leaning on the ground, and even in the air at appropriate power settings. I always lean as much as I can.

I did switch bottom plugs to fine wire, but I don't think that makes a difference.

Don't worry Dayton! BTW - I'm trying to install one of your quadrants into my -9A!

[mahlon_r]

Originally Posted by David Clifford

I have lead build up on the bottom plugs on my 0-235 L2C. I tried the high rpm shutdown method per Lyc, and just recently started adding the TCP fuel additive that is supposed to help. Well, after running through three tanks of fuel with the additive, I started to get hard starting and rough running. I pulled the plugs today and found the bottoms again built up with lead. Cleaned and rotated and she is running fine again. Doesn't look like the additive is doing anything.

Are you running REM37BY or equivalent plugs? If not you might try them. It won't fix the lead buildup but it might help with the operational ones.
Good Luck,
Mahlon
?The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

[frankh]

Originally Posted by RScott

If you go for mogas, be sure to check for alcohol. Mogas works great for my plane, but not always easy to get anymore. Kind of like 80 octane.

No need to bother to check for alcohol. it runs the same except it won't lean out quite so far..But it will still run quite happily Lean of peak if you have FI.

I have not run E10 at high altitude so cannot confirm rumours of phase seperation etc..but I have run it 12k for extended periods at below freezing with no issues.

[ed. Sentence on politics removed here. dr]
Frank

[David Clifford]

Originally Posted by mahlon_r

Are you running REM37BY or equivalent plugs? If not you might try them. It won't fix the lead buildup but it might help with the operational ones.
Good Luck,
Mahlon
?The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

Yes,,, I am using the REM37BY plugs as recommended by Lycoming. I have also tried the Marvel Mystery Oil prior to using the TCP with the same results. I am contemplating using a 50/50 mix of 100LL and autogas 93 Premium. Do I need to worry about the 10% ethanol added to the autofuel or are there any gas stations left that still sell pure fuel without ethanol? My C-152 does not have the mogas stc but at this point I am willing to experiment a little bit on the conservative side.

[airguy]

Originally Posted by RScott

BUT, for a homebuilt, you can use Decalin which has the same active ingredient as TCP, but a different and safer carrier. TCP is pretty hazardous & they say not to carry it in the airplane; Decalin no problem. Get it at Aircraft Spruce.

Actually, TCP *IS* the active ingredient - TCP is shorthand for the chemical TriCresyl Phosphate, this is the active lead scavenger. The bottle label "TCP" may also be used as a branding trademark, and different manufacturers may use different solvent to carry the TCP in solution, but tricresyl phosphate is the active ingredient you want. I'm not familiar with the Decalin formulation, so can't speak about that one.

"TCP" can be trademarked (and apparently is) to sell the lead scavenger product containing tricresyl phosphate, but they cannot trademark or patent the chemical itself. Any other lead scavenger product containing the same levels of tricresyl phosphate should perform similarly.

[RScott]

Greg is right about the active ingredient.

Find info about Decalin here:
http://www.decalinchemicals.com/fueladditive.html

When I talked to the guy about use in certified aircraft, it sounded like a one man operation. He answered the phone, "Hello", not "Decalin" or any business name. It may take some time for him to get approval for the product if he has no experience with the Feds.

I see elsewhere on his website that he has a Glastar.

[Dayton Murdock]

After talking with Frank I believe that I have been causing this issue all along. I have not been leaning during my ? mile taxi and take off. Carson City is at 4600? and running at full rich may be the cause of the lead nodules. Also an older gentleman had told me that Marvel Mystery Oil will help stop the lead build up. Any comments?

[Mike S]

I agree that taxing with the mixture rich has contributed to the problem, but as far as I know, MMO will not help with the lead balls.

MMO is, at least as I have been told, for lubricating the valve stems.

[frankh]

Originally Posted by Dayton Murdock

After talking with Frank I believe that I have been causing this issue all along. I have not been leaning during my ? mile taxi and take off. Carson City is at 4600? and running at full rich may be the cause of the lead nodules. Also an older gentleman had told me that Marvel Mystery Oil will help stop the lead build up. Any comments?

Leaning Agressively!! (like to where it only just runs) during taxi is absolutely the right thing to do..Detonation is a non issue at the minisule power setting required for taxiing.

I thought we were talking about take off power..where you should lean to best power.

Hold on the brakes and run to full power (or say 2300RPM if you can't hold it)...lean till RPM maxes out..push the mixture back in about 1/8th of an inch and take off.

Full power ROP will be in the order of 125F ROP.

Then see if you can cruise LOP of peak (you probably won't be able to but it will be worth a try) and that will kepp your top end much cleaner all round and save fuel into the bargain.

Hey if we get together in CVO this weekend can we fly some acro in your 4? We might be able to rig up my in cockpit video cam too..

Frank