GM 12680074 Spark Plug Assembly, Gas Eng Ign

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On all engines, the spark plugs are screwed into the top of each cylinder head and it must be noted that to get at the ignition coils and spark plugs, one has to remove the engine cover. Special equipment necessary for spark plug substitution are: a spark plug socket that screws onto a ratchet; an assortment of various extensions; a spark plug gap gage to measure and reset gaps on new spark plugs; optional, torque wrenches, to use in tightening. It is advisable to buy fresh plugs in advance, set the gap, and put them one by one, and be certain of which plug fits the engine. When all is done, let the engine cool before taking out any plug, and while waiting secure new plugs and examine them for defects and gap. The gap is measured by placing the correct thickness gauge between the electrodes at the tip of the plug with different producers recommending the wire type gauge that should be able to slide through the electrode gap with some resistance. If the gap is wrong then the adjuster on the gauge body can be used to bend the curved side Electrode slightly and keep the side Electrode over the centre Electrode and the porcelain insulator must be checked for cracks and ensure the gap is correct. If the spark is compressed, then blowing air should be used in blowing off any dirt or other material around the spark plugs so as not to fall into the cylinder while removing the spark plugs. The spark plug socket is fit over the plug and turned anti-clockwise to unseat it and this could require a socket and extension. The state of running of the engine should be evaluated through comparison of the spark plug with a chart. One of the new plugs is screwed in as tightly as it can be turned by hand and then tightened up further with a torque wrench or ratchet, this is best done with a short length of rubber hose threaded onto the plug end to help start the plug thread into place and avoid further damage to the threads. Last of all the spark plug wires or the ignition coils if replaced are fitted and the process is carried out on the rest of the spark plugs.

To prevent debris contamination, it is recommended to remove the ignition coils and use compressed air to clear debris around the spark plugs.

It is one spark plug per order