Replacing the Spark Plugs

Part of the annual maintenance program for a Spec Racer Ford is to replace the Spark Plugs. This is easiest to do if you are replacing the coolant as Spark Plug #1 can be difficult to access requiring the removal of the alternator and potentially the expansion tank.

Kanga Motorsports Spec Racer Ford Replacing Spark Plugs Remove the Alternator.JPG

Tools and Equipment:

  • New Spark Plugs: Motorcraft AGSF 24 C / AGSF 34 C / NGK TR6
  • Bendy 3/8 inch ratchet and extension
  • Spark Plug socket
  • Spark Plug gauge or feeler gauges
  • Magnetic pick up (optional)

Replacing the Spark Plugs

Before starting check the gap on the new spark plugs they should be between 0.035 and 0.040 using a Spark Plug gauge or feeler gauges. Don't trust that they were set correct at the factory. Also visually inspect the insulator to ensure there are no cracks incase they were dropped in transit.

Kanga Motorsports Spec Racer Ford Replacing Spark Plugs New Plugs.JPG

To access Spark Plug #1 you will need to remove the alternator. Then remove the plug wire and you should be able to get to the Spark Plug. If you are draining coolant or doing any coolant system maintenance where the expansion tank is removed then do the plugs at the same time. Having the tank out of the way isn't essential but it sure makes it easier.

Kanga Motorsports Spec Racer Ford Replacing Spark Plugs Number 1 Access.JPG

Disconnect the plug wire by pulling and pinching on the end cap. Do not pull from the wire as you can ruin the plug wires. Remove the spark plug using a Spark Plug socket with an extension and ratchet. A magnetic pick up tool can help get it out of the hole once undone. I have found the bendy 3/8 drive ratchet makes this a lot easier.

With the old spark plug removed you can now see the difference. Shiny brand new vs used.

Kanga Motorsports Spec Racer Ford Replacing Spark Plugs New vs Old.JPG

Place the new spark into the hole and use your fingers to ensure proper thread engagement. Then use the bendy ratchet to tighten in place. Don't start with the ratchet as you you might cross thread the aluminium threads and that can be a very bad day.

Clip the plug wire back in place and make sure it is secure.

Work you way done the engine replacing the other Spark Plugs as you go. The others are much easier to access.

Replace the alternator ensuring the belt is secure with correct tension.

If you removed the expansion tank you will also need to replace that with the AN wrenches and secure in place. Fill the car with coolant/water and run it for a little while until the thermostat opens to remove any air pockets.

Other Maintenance Articles

James Chartres

San Jose, CA