Spark Plug: Description and Operation

SPARK PLUGS
All engines use resistor spark plugs. They have resistance values ranging from 6,000 to 20,000 ohms when checked with at least a 1000 volt spark plug tester.

Do not use an ohm meter to check the resistance of the spark plugs. This will give an inaccurate reading.

Remove the spark plugs and examine them for burned electrodes and fouled, cracked or broken porcelain insulators. Keep plugs arranged in the order in which they were removed from the engine. An isolated plug displaying an abnormal condition indicates that a problem exists in the corresponding cylinder. Replace spark plugs at the intervals recommended in the - Lubrication and Maintenance.

Setting Spark Plug Electrode Gap:

Spark plugs that have low mileage may be cleaned and reused if not otherwise defective, carbon or oil fouled. Adjust the gap between the electrodes to the dimensions specified in the chart.

Special care should be used when installing spark plugs in this cylinder head spark plug wells. Be sure the plugs do not drop into the wells, damage to the electrodes can occur.

Always tighten spark plugs to the specified torque. Over tightening can cause distortion resulting in a change in the spark plug gap. Over tightening can also damage the cylinder head. Tighten spark plugs to 28 Nm (20 ft. lbs.) torque.

SPARK PLUG PLATINUM
The engine utilize platinum spark plugs. Refer to the maintenance schedule.

All engines use resistor spark plugs. They have resistance values ranging from 6,000 to 20,000 ohms when checked with at least a 1000 volt spark plug tester.

Do not use an ohm meter to check the resistance of the spark plugs. This will give an inaccurate reading.

Platinum Pads:

The spark plugs are double platinum and have a recommended service life of 100,000 miles for normal driving conditions per schedule A in this. The spark plugs have a recommended service life of 75,000 miles for severe driving conditions per schedule B. A thin platinum pad is welded to both electrode ends as show in the above diagram. Extreme care must be used to prevent spark plug cross threading, mis-gaping and ceramic insulator damage during plug removal and installation.

CAUTION: Cleaning of the platinum plug may damage the platinum tip.