PISTON PAWN® — Spark Plug Port FOD Guard (M18 / M14 / M12)

When a spark plug comes out, the open port becomes an open invitation for grit, washers, safety-wire clippings, or shop debris to drop where it shouldn’t. PISTON PAWN® is a non-threaded, drop-in plug designed to protect open spark plug holes during routine, room-temperature engine maintenance—helping prevent foreign object damage (FOD) before it starts.

Unlike generic tapered caps (quick, but not purpose-sized or depth-controlled) or threaded dehydrator plugs (excellent for storage, slower for day-to-day maintenance), PISTON PAWN® is built for the maintenance moment: fast in, fast out, secure by fit, and easy to spot with a Hi-Vis Yellow knob.

Designed and distributed in the USA by Swearingen 3D Works (Marion, Iowa), PISTON PAWN® was tested by our A&P staff at C17 and is now in extensive use by the fleet. Each set is made to order—prepared specifically for you and your bird.

What it fits

• M18 — Lycoming / Continental

• M14 — eMag Adapter

• M12 — Rotax

How it works

• Non-threaded “drop-in” design: intentionally undersized relative to the hole threads

• Weighted for stability at the cylinder end — quick protection you can feel.

• Protects open ports from accidental debris entry during typical maintenance steps

• Finger knob for quick insertion/removal—no tools required

Specifications

Color: Hi-Vis Yellow
Material: 3D-printed PETG (temperature limitation 83°C / 181°F)

M18 Size

• Plug reach: 0.82 in.

• Pawn overall length: 3.37 in.

• Installed height: 2.63 in.

• Finger knob: 0.79 in.

• Weight: 9.5 g

M14 Size

• Plug reach: 0.75 in.

• Pawn overall length: 2.99 in.

• Installed height: 2.23 in.

• Finger knob: 0.60 in.

• Weight: 5.2 g

M12 Size

• Plug reach: 0.76 in.

• Pawn overall length: 2.84 in.

• Installed height: 2.00 in.

• Finger knob: 0.59 in.

• Weight: 6.2 g

Use note

For room-temperature, non-compressive maintenance use only.

Ordering

Sold as sets of 4 tops or 6 tops.