installed (spark) plug depth - effect on combustion?
Thread Starter
Team Owner
Joined: Sep 2002
Posts: 22,209
Likes: 12
From: OBAMA IS HITLER
installed (spark) plug depth - effect on combustion?
I have AFR (CNC'd with TPIS' program) heads, AFR says the plug reach required for AFR heads is 5/8" (.625"). I'm looking into using shorter header plugs, the Accels are .420", which is .205" shorter.
AFR says these are too short. TPIS says they're fine. Naturally, I'm confused.
What effect will .205" less depth have with combustion & performance?
AFR says these are too short. TPIS says they're fine. Naturally, I'm confused.
What effect will .205" less depth have with combustion & performance?
Safety Car
Joined: Feb 1999
Posts: 3,631
Likes: 14
From: Fountain Hills AZ
I think you're confusing plug length with "reach". The "shorty" plugs don't protrude as far outside of the head to provide more clearance for headers. Reach refers to how far the plug extends into the cyl. If you were to use a shorter reach plug than the heads were designed for it's spark could be shrouded and be further away from where it's supposed to be for proper ignition.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Screw them both into the heads and measure the CC's of the combustion chambers with each plug. You can figure the two compression ratios from all your other data. If the difference is more than .05, I'll be amazed. Time for racing gasoline.
RACE ON!!!
RACE ON!!!
