GUARD 3V5857 - Caterpillar

Ignition systems can cause electrical shocks. Avoid contacting the ignition system components and wiring.Do not attempt to remove the valve covers when the engine is operating. The transformers are grounded to the valve covers. Personal injury or death may result and the ignition system will be damaged if the valve covers are removed during engine operation. The engine will not operate without the valve covers.
Maintenance of the spark plugs is required in order to achieve the following benefits:
Normal fuel consumption
Normal level of emissions
Maximum service life of the spark plugsThe service life of the spark plugs is affected by fouling due to deposits from the oil and by peak voltage. Maintenance of the ignition system is also affected by voltage. Higher voltage is required by higher inlet manifold air pressure and a higher compression ratio. Higher voltage reduces the service life of components such as spark plugs, wires, and transformers.
Illustration 1 g00712201
(1) Wiring harness
(2) Transformer assembly
(3) Spark plug Removing the Spark Plug
Do not pull on the wires. Damage to the wiring harness may result.
Disconnect wiring harness (1) from transformer assembly (2).
Remove transformer assembly (2).
Ensure that the area around spark plug (3) is clean. Use a 2P-5481 Deep Well Socket with an extension in order to remove spark plug (3). Cleaning the Spark Plug
Clean the spark plug with a nonmetallic brush. Inspect the spark plug for the following conditions: corrosion, pitting and wear. If the spark plug is in good condition, the spark plug may be installed. If the spark plug is not in good condition, install a new spark plug. Check the spark plug gap before installing the spark plug. The spark plug gap depends on the compression ratio of the engine.
Set spark plug gap to 0.28 0.05 mm (0.011 0.002 inch) for the compression ratio of 11.3:1.
Set spark plug gap to 0.46 0.05 mm (0.018 0.002 inch) for the compression ratio of 8.5:1.Installing the Spark Plug
Install the spark plug.
Tighten spark plug (3) to 30 4 N m (22 3 lb ft).
Install transformer assembly (2). Ensure that the transformer assembly is aligned with the wiring harness socket. Ensure that the wiring harness socket is oriented toward the center of the engine.
Connect wiring harness (1).