Indexing Spark Plugs

Here is an interesting article I came upon. It talks about the process of "indexing" one's spark plugs. The idea is to position the plug in such a way that the opening of the gap is facing the combustion area to place the spark in a more advantageous position to ignite the fuel/air mixture. While it makes sense from a logical stand point, there seems to be much debate about how much if any effect it actually has on increasing power and/or fuel efficiency by enhancing combustion. By using a set of specially designed crush washers or indexing washers of varying thicknesses, you can seat the plug so that the open end of the gap will face the combustion chamber. Some say it does nothing at all while others say it has a minimally positive effect and others still stay that there are many variables with different engine/piston configurations. It is not something that I intend to run out and change today, but the next time I change the plugs which will probably be next spring, I'll certainly look into it. Anyway, it is something that is interesting and that I thought I'd put out here for you guys to banter around. Here is a link to Advance Auto Parts with a brief discussion on the process. You can also google it and read a wealth of information on the subject. http://corp.advanceautoparts.com/english/youcan/asp/pht/pht20001001sp.asp

All this would certainly be interesting to find out... if there 'is' anything to find out. I'm certainly not an expert on such subjects and I'm always open to new information but I do know that combustion chamber technology has been pretty thoroughly run thru the mill. Spark plug placement within the chamber has always been a 'sticky wicket' because of valve placement, flame propagation, and all those other techy things. I just can't imagine that they missed out on which direction to point the plug gap.

Good find and possibly worth reading, but I really doubt that the effort involved will yield much in the SilverWing "wheelie zone".

From the referenced link...

"Before we dig into spark plug indexing, we should point out that every engine responds differently to indexed spark plugs. Why? The shape of the combustion chamber, the shape of the piston dome, the type of ignition system and many other variables influence the "location" of the spark plug in the cylinder head... ...When it comes to performance, some engine combinations simply respond better to indexed spark plugs than others."

and

"Generally speaking, the idea of indexing is to position the spark plug so that its gap is facing the center of the cylinder, angled slightly toward the exhaust valve—the most common arrangement. (Some engines work better with other gap locations.) "

and

"Real-world power gains vary. Some engines or combinations respond differently than others."

These statements lead me to the following conclusion: This might be of value or it might not. Personally I won't lose a lot of sleep over "research" that comes complete with it's own disclaimer that the results may very well be minimal or nonexistant (my summary).

The theory is valid, but the return as the "researcher" infers may be so minor as to make the effort pointless.

I wonder if the very large engineering departments at the OEM's have ever thought of this?? ?

I have a neighbor who is a mechanic for a drag racing team who says they sometimes index sparkplugs but that he really thinks it does about as much as sacrificing a chicken at midnight in a crossroads. His opinion is that a very small shift in the wind makes a lot more difference in quarter mile times.

'Serious' spark-plugs have the outer electrode up inside the plug rather than hanging off the bottom, thus giving a better spark pattern.

exavid wrote:

thinks it does about as much as sacrificing a chicken at midnight in a crossroads.

Do you have anymore information on this ... there is a new rooster across the road that I would be willing to test with.

Hey Bill!
Just try the 350 degree peanut oil sacrifice, don't forget the egg wash and seasoned flour.

Wes

350 degree peanut oil sacrifice,

I don't think my oven gets that hot.

Sorry I wasn't more explicit; 350 degree oil in a deep fryer.
Please do not test oil temperature with fingers, or any other extremity.

Wes

www.amazon.com Brisk-AR 10ZS. $ 17.98 May cost more but you won't have to worry about placement and sometimes things that cost more are better.

When inserting the plugs use snake oil to lubricate the threads. I find the Namaqua Dwarf Adder oil to be the best as the heat from the cylinders doesn't 'cook it', so the plugs are easy to extract, in fact I can unscrew mine just using my fingers. In the UK, Namaqua Dwarf Adder oil is available from Wilkinsons, B&M Bargains and other good toy stores. American cousins could try Walmart, Australian cousins (twice removed) can use Great White Urine instead.

Cheers,

Are you kidding me? I don't see myself pissing on my spark plugs. What's up with that? Try pissing on a frozen padlock.

Tinman,
Is the padlock inside or outside the house?

I don't know if anyone has told you but you're in CANADA. For sixty four years you've been thinking you live (exist) in Australia (Where men are men and sheep are scared!).

(Has this thread been high-jacked enough yet?)

Cheers,

Who convinces the shark to pee in a cup, and I want to know who the unlucky Urologist that has to tell the Great White that he has been swimming with the wrong piece of tail.

If adder oil is nor available, Melaleuca (tea tree oil) is an okay substitute.

Tarmacburner ,It wasn't me ,It was a roughneck miner trying to unlock the door to the dynamite shack .( Kaboom )
I think he was australian .

Tarmacburner.

I was never a professional mechanic or like they call them in Alaska (mecanic) Ha Ha but I did turn wrenches for 10 years and I believe that if you can remove the spark plug with just your fingers, than you have not correctly seated the plug and therefore allow exhaust gasses to escape and you would have the chance of blowing your plug right out the top of your head. :lol!:

tarmacburner2 wrote:

.... in Australia (Where men are men and sheep are scared!).

But only the female ones. Nothing weird about Aussies. The Welsh however!




Apologies to anyone offended by the above.

I'm all right then; my forebears were Irish - three of them anyway (who's been sleeping in my porridge?)