Threads on spark plugs
Posted: Thu Jan 28, 2016 8:09 pm
Has the thread on the NGK A6 spark plug changed ? I bought one a couple of weeks ago and the thread on the head didn't suit it. 
Not that I know of..... Check the thread of you old one against the new one. It could be a dammaged thread in the head.
NGK A6 spark plug
Thread Size: 18mm
Thread Pitch: 1.5mm
Seat Type: Gasket
Resistor: No
Reach: 12mm (.472")
Hex Size: 13/16" (21mm)
Terminal Type: Removable Nut
Overall Height: ISO
Gap: .028" (0.7mm)
Center Electrode
Material: Nickel
Type: Standard
Size: 2.5mm
Projection: Non-Projected
Ground Electrode
Material: Nickel
Type: Standard
Quantity: 1
Specifications
Torque Specs: Cast Iron: 25.3-32.5 lb. ft. Aluminum: 25.3-28.9 lb. ft.
Brand: NGK
Heat Range: 6
Longevity: 30k