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How to Clean Aircraft Spark Plugs

Aircraft are, by nature, far more maintenance-dependent than automobiles. Whereas an automobile breakdown might prove inconvenient or costly, when a pilots ride breaks down the closest tow truck is likely to be several thousand feet below. Cleaning an aircrafts spark plugs isnt really any different than cleaning any other gas engines spark plugs, and should be part of any regularly-scheduled service interval.

Instructions

1

Remove the spark plugs from your engine. This procedure will vary greatly by engine and airframe, but most are designed with regular plug maintenance in mind. Removing plugs from an aircraft engine is very similar to removing them from a car engine; the primary difference is that many aircraft use thread-on plug wires instead of automotive-style plug-ins. To remove threaded plug wires, simply unscrew them from the plug ends.

2

Drop the spark plugs -- electrode-end down -- into your mason jars. Lower them carefully so as not to damage the slugs. You may need two or more jars to hold the plugs. Pour your naptha solvent onto the jars to a depth of about one inch, or enough to cover the plug threads. Try to avoid pouring the solvent over the tops of the plugs. Allow them to sit in the solvent for 30 minutes.

3

Remove the plugs from the solvent. You can allow them to air dry, but you can dry them in seconds using the air supply from your sandblasting setup. At this point, the carbon on the plugs should be soft enough to remove with the baking soda blasting media.

4

Fill your sandblaster hopper with baking soda and trigger the sandblaster to purge any residual sand from the system. Turn the sandblasting pressure up to between 150 and 200 psi.

5

Hold your plug tip about three to five inches from the electrode and spray it down with baking soda. Rotate the plug to clean all around the electrode tip and the ground strap. You can remove stubborn carbon deposits by lightly scraping them with the end of your gun or a copper wire brush. Continue blasting the plug until its free of all discoloration and carbon. Repeat with your remaining plugs.

6

Fill your soup pot with water and place it on an electric stove to boil. Drop the plugs one at a time into the water to dissolve the baking soda. This is where the whole process comes together. Mechanics have been sandblasting spark plugs for years, but the sand tends to get trapped inside the plug and lead to later fouling. Baking soda dissolves in water, but it isnt aggressive enough to remove really hard carbon deposits without prior softening with a solvent like naptha.

7

Dry the plugs with compressed air and reinstall them into the engine in the reverse order of removal.