Indexing sparkplugs anyone do it?

[Talkwrench]

Any of you guys index your sparkplugs? Was thinking about doing it on my 360 as its time to change the plugs. What is the best position if anyone knows?

[Supercuda]

Indexing sparkplugs is usually reserved for high-dollar race engines. It is usually done in order to achieve two things: 1. Clearing a very tight combustion chamber (think exotic piston dome); 2. Consitent firing under less-than-ideal conditions (think turbulence and high rpm). On most engines,indexing is only going to give you an infinitessimal power increase, not worth the extensive effort involved. The ideal location for the electrode is generally with the opening towards the exhaust valve.

[Talkwrench]

I would have thought the "opening' would have been between facing the top of the piston and or towards the intake?? Mmm you have me thinking now , can you explain?

[Katfish]

Good info here, I've thought about it, but never followed through.

http://www.dodgeram.org/tech/gas/spark_plugs/s_plug%20_indexing.htm

[HP2]

Indexed plugs in one of my drag cars once. Can't say I saw any huge improvements for the effort. Honestly, there was enough variation between driver and atmospheric conditions to make it tought to validate improvements over just installing fresh plug.

[71chally416]

Not worth the effort IMO. If ya wanna do something you'll feel every time you push the gas pedal do something with the deficient heads and don't worry about the trick of the week stuff that if you're lucky might be worth .001 on your ET slip.

[Supercuda]

The theory behind facing the opening of the spark plug gap towards the exhaust valve, is that you do not want the incoming intake charge to "blow out" the flame before it can start moving across the combustion chamber. Turbulence of the intake charge is necessary for good flame front travel and good power production. This is also a recipe for disaster for the spark and its resulting flame kernel. Presumably, the ground electrode will shield the flame kernel from the incoming charge, to allow a good burn to start. Aiming the gap towards the exhaust valve also supports flame travel. Yes, it's a stretch; yes, it seems like overkill. That's why most people don't do it. It just isn't worth the hassle for the rewards reaped.

[Talkwrench]

Its all interesting stuff. We have had alot of feed back and results on our old Holden site in OZ, mainly things like easier starting, mileage etc. It is only effort and next to no cost perhaps a sparkplug or two extra. I will admit that doing on a inline 6 cylinder is an easy job on a V8 thats altogether different...