How to index spark plugs

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Another weHow tip on inexpensive performance improvement! Indexing the spark plug can be considered small but cheap (free if you are lucky) way to improve engine performance. We ain't talking big but a way to make sure your engine gets a complete burn.

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Instructions

Difficulty: Moderately Easy

Things You’ll Need:

Spark plug socket
Socket wrench
spark plug indexing washers

Step1

Open hood and remove spark plugs.

Step2

Mark each spark plug where the electrode is attached to the spark plug body.

Step3

Identify where the exhaust valve is located on your engine block.

Step4

Screw in a spark plug and check if the mark on the spark plug is pointing away from the exhaust valve. If they do not line up, use indexing washers (they come in different thicknesses) to align the electrode away from the exhaust valve.

By pointing the spark plug electrode away from the center of the chamber, it provides unobstructed spread of the spark flame.

Tips & Warnings

Copper indexing washers are the best because they its soft metal and will allow some give when tightening down the spark plugs.

Comments

neilj said

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on 4/27/2008 I'm sure it is Moderately Easy.

But for those of us that don't know the other terminology, it needs an illustration.

I've gapped plugs, dribbled oil on their threads, and screwed them in. I don't know if I ever noticed anything in the empty holes besides darkness. My cylinders have four valves -- can I recognize which one is the exhaust valve if I look in there?

You also offered another point of reference, "the center of the chamber," at which to point the open spark. Would the center of the chamber be any easier to recognize than the exhaust valve?

Thanks,
-Neil-