Spark Plug Gasket Source

[ejboyd5]

I recently had need to source some additional solid copper gaskets to adjust the 3/4“ reach of standard spark plugs to eliminate thread protrusion into the compression chamber of a 1956 300 SL engine. Being aware of the difficulties encountered in finding small quantities of Champion N-674 or N-667 gaskets, I went directly to Aircraft Spruce & Speciality Co,www.aircraftspruce.com/ (link is external) and was able to find exactly what I needed: 14 mm copper gaskets, 0.060” thick, $0.49 each, no minimum order. Delivery time from their Georgia facility was approximately five days spanning a weekend. As should be known, when using the earlier 300 SL heads, each spark plug requires two 0.060“ solid copper gaskets in addition to its supplied compression gasket to remedy the thread protrusion problem. The additional gaskets are not necessary if using a later Roadster head with the number ”19“ cast on its exterior as these heads are made differently to accommodate 3/4” (19mm) reach spark plugs without thread protrusion.

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