Spark plugs

[sneedrv-6]

Trying to see what sparks plugs are supposed to go in the 0360-a1ad (9.5 compression) with air flow performance injection system engine. The top plugs are on a bendix mag and would like to get new correct plugs. Searched lycoming manual with no luck, searched the forums with no luck (1 dead link to lycoming). Currently I am running unison 40E's. Crazy that a 30k engine does not have the recommended plug in the manual and no phone number on lycoming's site.

thanks for any input,

Jason

RV-6

[deek]

I would ask the engine builder what plugs they recommend. With 9.5:1 slugs I'm afraid Lycoming will defer to your engine shop.

[AK4x4]

The plugs listed in the parts catalog for that engine are REM40E's. The most current list of approved plugs (Lycoming SI-1042Z) shows the REM37BY, REM38E, and REM40E as approved. However this doesn't really apply as your engine isn't stock. The engine builder should know the correct plug. If I were to recommend a plug for the engine I would use the Tempest UREM38E if the plug leads were 5/8" thread or URHM38E if the leads are 3/4" thread. This assumes that the cylinders are short reach (between 3/8" and 7/16" ish of threads in the plug holes) plug type. Good Luck, Russ