SEAL-U-CUP 1672301 - 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.
The use of spark plugs with precombustion chambers is restricted to generator set applications.Note: Condensation can form in spark plugs that have precombustion chambers. This condition can cause difficulty for cold start-ups. To avoid condensation, maintain the coolant in the cylinder block at a minimum temperature of 43 °C (110 °F) continuously.The 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, lower emissions levels, a higher compression ratio, or retardation of the timing. Higher voltage reduces the service life of components such as spark plugs, wires, and transformers.The service life of the spark plug is different for different applications. The service life of the spark plug is approximately 2000 service hours. The spark plug may be good for a period beyond 2000 service hours. To help predict the spark plug service life, use Cat Electronic Technician (ET) to monitor the “Cylinder #X Transformer Secondary Output Voltage Percentage” parameter. The value of this parameter will increase as the spark plug gap wears over time. Experience at the particular site will help to determine the proper interval for replacement of the spark plugs.If a diagnostic code is generated for the ignition transformer secondary circuit, the spark plug should be replaced. Misfire and a cold cylinder are other indications of a worn spark plug. Use Cat ET to monitor the exhaust port temperatures to locate a cold cylinder.Removing the Spark Plug
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.
Illustration 1 g03779503
(1) Valve cover
(2) Bolt
(3) Washer
(4) Seal
Remove bolts (2) and washers (3). Remove valve cover (1). Inspect seal (4). If the seal appears to be worn or damaged, discard the seal and use a new seal for assembly.
Pulling on the wiring harness may break the wires. Do not pull on the wiring harness.
Illustration 2 g03779598
(5) Transformer
(6) Extender and lip seal
(7) Spark plug
(8) Wiring harness
Disconnect wiring harness (8) from transformer (5). Be careful while depressing the retainer clip away from the connector. Remove transformer (5).
Inspect extender and lip seal (6). If the seal is worn or damaged, replace with a new seal. If the extender shows signs of damage, replace with a new extender.