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Spark plug size ???


Well-known member
looking for spark plug size for 0540 lycoming for cht sensor they list them for 10mm 14mm and 18mm denso plugs Thanks

Slidin Gator

Well-known member
18 mm spark plug threads. Note that I have found the spark plug base temp readings (using laser heat gun, not ring CHT) to be 50 to 100 Deg F less than the bayonet CHT's that Lycoming specifies.