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Quick Job guide How to change a spark plug

In this guide I will teach you how to change your spark plug

This simple and easy task is ideal for the new enthusiast to classic motoring, the spark plug can also tell you alot about how your engine is running, so lets crack on.

firstly rule 1 never take all the spark plugs out at the same time, this will leed to confusion as to which HT lead goes where.

Step 1, remove the HT lead, this is the long, thich flex wire with a rubber cap on the end, pull the cap and it should “pop” of the end of the spark plug.

Step 2, using a spark plug wrench or socket, tap and turn in an anti clockwise direction, you may need to give it a good wack to get it started, it should then unscrew easily.

Step 3, remove the plug, you will feel the plug getting looser, when it is loose carefully remove by hand, you should now be able to see the sparking part of the plug. depending on the colour this will be able to tell you how well your engine is running.

  • Clean and white with no deposits – the mixture is weak
  • black and sooty – the mixture is too rich, should it be oily too then its likley that the engine is worn
  • light tan to greyish colour – the mixture is correct.

Step 4, place the new plug into its location and start to turn it clockwise (screwing it in) by hand, when you can no linger turn it by hand put the wrench or socket on and continue untill it stops. the plug does not need to be over tightened but be sure that it is tight.

Step 5, replace the HT lead on the end of the plug, it should “pop” into place.

Step 6, repeat the process with each spark plug in turn.

So there we go a nice simple task that should take no more than 10 mins to do depending on how many plugs you need to change over.


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