Indexing sparkplugs???

[Detman101]

This made me think a bit....



Spark Plug Indexing
A simple method of increasing Horsepower and Engine Efficiency



Simple things are often overlooked by complicated minds. I must confess I felt downright stupid when I realized that spark plugs often don?t face the incoming turbulent fuel mixture. Common sense would dictate that the back of the spark plug electrode, if positioned in the head improperly, would actually retard combustion, by shrouding the spark, as opposed to placing the open spark towards the air-gas and thereby increase the percentage of burn.

It is amazing how advanced physics training can overshadow common sense. I went to the expense and trouble of investing in cams, carburetors, porting, polishing, power electric?s, etc., and yet it never occurred to me to point the open spark toward the fuel.

You would think that the spark plug manufacturers would direct the consumer to do this through the written instructions on the spark plug package. Instead, they exhort the high-tech virtuosity of palladium, platinum, or gold materials to induce different types of levels of spark. That?s impressive, and it?s nice that rare expensive metals are sold to us for under ten bucks, but couldn?t they tell us how to install them properly?

What about the factory that is striving to produce a better product for the consumer? Again, common sense suggests that the Factory wouldn?t overlook such a simple thing as pointing the spark plugs in the right direction.


Now, let?s get down to business and figure out how to apply this to our GSes...

[scotty]

I didn't read the post but most engine tuners say that the indexing is a waste of time because any theoretical increases can not be measured on any dino.

[Jethro]

any theoretical increases can not be measured on any dino.

They've been dead for a few years now. Might you mean Dyno?

Just kidding. I'm sick of making fun of myself today, it's been too easy.

How would you index them, crush washers I guess? Man, I take my plugs out so often to check compression, do plug reads, whatever, that I'd spend a fortune on crush washers!

[Anonymous]

Simple things are often overlooked by complicated minds. I must confess I felt downright stupid when I realized that spark plugs often don?t face the incoming turbulent fuel mixture.

Sure they do. Our combustion chambers (the 4 valve motors, at least) do not look at all like the picture. The spark plug is central and there is a squish band all the way around. The incoming charge floods the cylinder and the turbulence is in a "barrel rolling" motion (not a swirling motion as in 2 valve motors) which collapses as the piston nears TDC and the squish band forces a high velocity jet of charge towards the center of the combustion chamber (where the spark plug is) from all around the cylinder. So it doesn't matter which way the plug is facing, it is surrounded by fresh charge. The much better filling and combustion efficiency of the 4 valve layout is one of the reasons that the 4 valve engines need less valve lift and overlap and can idle nicely all day and make big power at the same time. This theory may have held some weight about 50 years ago when wedge shaped combustion chambers and off-center plugs were common, but it is no longer valid with 4 valve designs.

Mark

[scotty]

any theoretical increases can not be measured on any dino.

They've been dead for a few years now. Might you mean Dyno?

Just kidding. I'm sick of making fun of myself today, it's been too easy.

How would you index them, crush washers I guess? Man, I take my plugs out so often to check compression, do plug reads, whatever, that I'd spend a fortune on crush washers!

well jethro 8O there is no measurable increas in dinasours either--nyaaaa so there

[wrench]

You guys are forgetting we had a dino roaring on the forum a few days ago

[scotty]

You guys are forgetting we had a dino roaring on the forum a few days ago

we argue and disagree but just let saomeone insult one of our own.

[duaneage]

Absolute BS that is. What kind of incoming turbulence is there when the valves are closed?

[RacingJake]

The easy way is just cut off some of the side electrode so the spark jumps off the tip side of the center electrode. A lot of folks do it that way, even those NASCAR boys. I do it too on my Falcon cause it would take to many plugs to find 8 that would work.

[displaced]

Absolute BS that is. What kind of incoming turbulence is there when the valves are closed?

isnt it a fact that the plug may fire before both valves are closed and i believe that there is still swirl going on even during combustion--i dont believe in plug indexing though

BTW Jake please explain your plug mod a little more so this old goat can visualize it.

[Detman101]

Simple things are often overlooked by complicated minds. I must confess I felt downright stupid when I realized that spark plugs often don?t face the incoming turbulent fuel mixture.

Sure they do. Our combustion chambers (the 4 valve motors, at least) do not look at all like the picture. The spark plug is central and there is a squish band all the way around. The incoming charge floods the cylinder and the turbulence is in a "barrel rolling" motion (not a swirling motion as in 2 valve motors) which collapses as the piston nears TDC and the squish band forces a high velocity jet of charge towards the center of the combustion chamber (where the spark plug is) from all around the cylinder. So it doesn't matter which way the plug is facing, it is surrounded by fresh charge. The much better filling and combustion efficiency of the 4 valve layout is one of the reasons that the 4 valve engines need less valve lift and overlap and can idle nicely all day and make big power at the same time. This theory may have held some weight about 50 years ago when wedge shaped combustion chambers and off-center plugs were common, but it is no longer valid with 4 valve designs.

Mark

Understood, thanks man!!

[RacingJake]

Here's a pic with the side electrode cut down. This also help's if your're running big dome's or big valve's cause they can get real close.