Spark plug threads

[Jonny69]

Does anyone know the pitch for 10mm and 14mm spark plug threads? Looking to buy a tap for each, handy if I can use my existing NGK BP6ES plugs which are 14mm.

 

[neil-ste]

I think the thread pitch is 1.25mm

 

[Dogbreath]

M10x1.25 and M14x1.25 are the common ones, but it's possible to get M10x1.0mm spark plugs.

 

[Mattius]

14 x 1.25 for ngk bp6es iirc, i run them but aint checked in a while.

taps are bloody expensive in that size, i found thread chasers where a third of the price and do nearly the same job.

 

[Jonny69]

Will they do a new thread in steel though? I just dug out one of my 10mm plugs and it looks like it's a shade over 1mm, so probably 1.25mm. Just going to stick a vernier on it to check...

 

[Mattius]

they wont do it through brand new steel, but if there was thread there then it will fix it, i used one to sort my lambda sensor mount in exhaust.

otherwise if your drilling a new hole your needing a tap, and looking at £25 for one!