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Wide gap spark plugs

RCP Phx

NAXJA Forum User
Location
Phoenix,Az
I'm currently running NGK ZFR5N plugs but I need at least a .044" plug? It's a extended tip plug.
 
Higher coil voltage and a MSD.
 
Cant pull the gap larger? Or are you concerned about piston contact?

I used Champion rc9yc from the renix years on my forced induction 4.0L. They have a much more shallow tip compared to the extended plugs. The heat range may not work out for you.
 
When I spoke with NGK Friday, they only recommended a max of .008" larger. There is no concern with plug length but I really need to get to about .050-.065" gap. Today I'm going to pick-up some factort plugs and see how far I can take them!
 
Have you asked MSD if they have a recommended plug for your application?
 
I've talked to Champion, NGK, Autolite, and Accel with all the same answers regarding my thread/reach/protrusion/gap.
 
I forgot to add hex size(not critical/gasketed vs taper seat/ ans heat range. Seven items isn't to much to ask for!
 
I safely/concertively was able to get .047" out of a new set of ZFR5N's, could probably stretch that a little more but the radius of ground electrode comes into play. I can certainly get by with this to get started and see what the future holds.
 
I think .047" will be fine. There's a point of diminishing returns with
extending plug gaps; and remember they will widen as they wear...

Plus the MSD will also give faster wear.
 
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