indexing spark plugs...any benefit to it

soap said:
Depends on where the quench area is in your combustion chamber.......different for each application.

--Joe
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well yes, Im aware of that, but is there a general area. Im using chevy LS heads, the quench area isdirectly across from the valves, but would it benefit to point the open side more toward the exhaust valve, intake, or dead center
 
gub said:
What does it mean to index a spark plug?
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you point the open side of the spark plug (opposite of the grounding tip) toward the quench area. it is supposed to initiate a better burn, more fuel efficient, etc.

It basically points the spark at the air/fuel mixture.
 
cjmatt said:
well yes, Im aware of that, but is there a general area. Im using chevy LS heads, the quench area isdirectly across from the valves, but would it benefit to point the open side more toward the exhaust valve, intake, or dead center
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I would point the gap dead center and facing down in the chamber towards the top of the piston. I don't think you have much to gain as the chamber is very efficient. On a oldschool SBC with a crappy chamber, You could pickup some numbers pretty easily.

Never did much testing on that one the gains are usually so minimal we won't see them on the chassis dyno as it gets inside the 1% error of the run to run data.
 
Sean said:
I would point the gap dead center and facing down in the chamber towards the top of the piston. I don't think you have much to gain as the chamber is very efficient. On a oldschool SBC with a crappy chamber, You could pickup some numbers pretty easily.

Never did much testing on that one the gains are usually so minimal we won't see them on the chassis dyno as it gets inside the 1% error of the run to run data.
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if you face the electrode to the piston, isnt the exact opposite of pointing the gap toward the quench area? It would shield the quench
 
cjmatt said:
if you face the electrode to the piston, isnt the exact opposite of pointing the gap toward the quench area? It would shield the quench
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You can try different positions, but I doubt it will matter much and the best position must be tested for anyways.,but using stock heads the only way to do this is to use gasket seat and not tappered seat plugs IF the heads have room. The best way I have seen is to point the gap at the exhuast valve. But your mileage may very. Depends on the head and the piston.

To boot though I really doubt it is going to matter a whole lot anyways. It really seems to be critical with dome pistons less so with everything else.
 
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