Fine wire plug cleaning

[Tankerpilot75]

I?m sure this has probably been discussed many times but I still need the information. I heard from a person I respect, that fine fine wire plugs should never be cleaned using an abrasive blast plug cleaner. He said it shortens plug life and could seriously damage fine wire plugs.

However I was looking at a Champion plug maintenance manual the other day and while it didn?t specifically say one way or the other; it appeared to me that it recommended cleaning both massive and fine wire plugs using the Champion plug blast cleaner and the Champion plug vibration cleaner. Then use their testing equipment to confirm proper plug operation.

I really need to keep the engine lean for taxi operation because of poor break in ring seating after a prop strike rebuild and the use of 10W50 instead of mineral oil during the break-in after rebuild. I purchased the airplane from the original builder about ten hours after the rebuild (150 TT). He was getting too elderly to continue to safely fly and knew it after his OSH prop strike. He fully disclosed the prop strike and professional G&N engine inspection/rebuild at the time of purchase but I didn?t understand the importance of mineral oil in the seating of the new rings to the re-honed cylinders (my first experience at aircraft ownership) and had an oil change accomplished during the prebuy/condition inspection which installed the 15W50.

Neither the seller nor the prebuy inspector expressed any concern about my choice of oil. I eventually switched back to mineral oil after experiencing serious plug fouling problems for the next 20 plus hours. I used mineral oil for the next 50 hours. This significantly improved the ring seating but left things still a little less than perfect. Oil consumption is now down to about one quart every 15 hours and compressions are uniform at around 76-78/80.

As a result plug fouling during run up can still occur after lengthy taxi times. Superior engine folks whom I?ve discussed this with tell me not to be too concerned because it will continue to improve over time. And in fact it has gotten better but #2 cylinder plugs still foul out if I taxi for over five minutes with the engine not properly leaned out or it has set for a while in the hanger (usually both).

At my last condition inspection to help address this issue I installed fine wire plugs on the lower row and left massive plugs on top to see if I could notice any difference in operation and to save plug upgrade cost. I personally liked the results and plan to do the other row this April on my next condition inspection by cleaning the fine wire plugs and moving them to the top row and installation of another four new fine wire plugs on the bottom row.

Now back to my question: can I (should I) use an abrasive blast cleaner on fine wire plugs for cleaning? Any plug experts?

[ArlingtonRV]

Page 4-6 also mentions not to use glass beads on massives either.

[Raymo]

I hadn't seen the above recommending cleaning process but felt the fine wire plugs (top set only) looked so fragile, I opted not to blast them during my condition inspection. I used a pick to break any lead free and hit them with a blast of air. I then confirmed they met resistance requirements (<5k Ohm) before re-installing. There wasn't much else on them, in my case.

I have auto-plugs (P-Mag) on the bottom set and replaced them.

Your oil burn sounds pretty normal, along with compressions. Leaning during ground ops is a very good practice to avoid lead fouling, which would not be related to oil consumption and associated fouling. Lean aggressively, such that the engine stumbles if the throttle is advanced much to avoid an attempted take-off while lean.

[Larco]

I use and comes recommended by Champion. Tip your plugs upside down in holes punched in cardboard, fill the electrode area and leave overnight. Not expensive and does a good job IMHO

Hoppe's No. 9 Gun Bore Cleaner