still dying to knw - what would happen if my engine required the longer park plug, but i put in the short spark plugs? woudlnt start? would notice it big time?
If the threads do not reach all the way down into the head, but the engine ran ok and you left it like that, the bottom of the threads in the head will begin to soot up and when you did try to put in the correct length plugs they would not be able to thread in without busting up all the carbon and flaking it into the top of the cylinder. That could end up holding open a valve or worse.
Ayuh,.... Best case, what Mac says will happen,....
Worse case, ya develop a lean condition, Detonation sets in, 'n the sharp threads would be the 1st bits of the cylinder consumed by said Detonation,.....
Long plugs in the older heads,
Could impact the pistons, though unlikely on a factory spec'ed motor,....
