Sizes of Spark Plugs

There are three widely available spark plug sizes used. These are 0.8125 inches, 0.750 inches and 0.6875 inches long. All of them have gaps between 0.035 inch to 0.070 inches.


This is a device employed in internal combustion engines. This is an engine that gets its power by way of gases that explode within a combustion chamber. What the spark does is start the air fuel mixture.

Majority of cars have four-stroke gas engines. What this signifies is that there are four increments or strokes in the moving components within the engine for every rotation.

A piston is housed in the cylinder. The piston moves up and down to squeeze the gas. The exhaust gases are drawn out following the combustion.

The piston is run by an arm that is linked to the crankshaft. The crankshaft goes into the engine’s bottom. During each rotation, the piston goes up and down twice.

Whatever the spark plug size is, it is situated on the cylinder’s top. This is where the air fuel is compressed. The spark’s tip is within the engine at the wall of the cylinder. The spark’s other end is outside and hooked to a wire. This wire links the spark and the distributor.

How the Device Works

When the piston starts moving, the air fuel mix is compressed. The distributor relays energy on the wire. When this gets to the spark, the plug goes off. This ignites the mixture.

The explosion within the chamber makes the piston go down. This happens with all the cylinders one after the other. When the piston goes up again, it opens the exhaust valve. The gas is ejected from the exhaust pipes.


Because it is so important, the spark has to be maintained. Sparks in old cars are made of copper. These require yearly checkup. The best time to replace these would be during the tune up. If it is dirty, emery paper can be used to clean it up.

Make sure that the spark has the proper gaps. This is specified in
the user manual. Too little or too much space between the plug’s top and the steel finger will make them impossible to run.

Aside from the spark plug sizes, the material used is another factor. One of the best is platinum as it is low maintenance. Some of these are capable of lasting 160,934 km or over 100,000 miles. Even with platinum sparks, the gap must still be proper.

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