3618 Engine Caterpillar

Calibration Check

Alarms and shutoffs must function properly. Alarms provide timely warning to the operator. Shutoffs help to prevent damage to the engine. It is impossible to determine if the engine protective devices are in good working order during normal operation. Malfunctions must be simulated in order to test the engine protective devices.

A calibration check of the engine protective devices will ensure that the alarms and shutoffs activate at the setpoints. Ensure that the engine protective devices are functioning properly.

To prevent damage to the engine, only authorized service personnel or your Caterpillar dealer should perform the tests.

• For the calibration of temperature contactors, see Special Instruction, SEHS9827, "Calibration of Temperature Contactors".

• For the calibration of pressure contactors, see Special Instruction, SEHS9828, "Calibration of Pressure Contactors".

Consult your Caterpillar dealer or refer to the Service Manual for more information.

Check the Magnetic Pickups

Illustration 1	g00705318
(1) Magnetic pickup (2) Flywheel ring gear

1. Clean the face of the magnet. Check the condition of the magnetic pickup.

2. Measure the resistance of the magnetic pickup. Resistance should be about 150 ohms.

3. If necessary, remove the magnetic pickup from the flywheel housing.

Note: Some sensors have flat bottoms but other sensors may have small tips. Ensure that the tip of the sensor contacts the center point (highest point) of the gear tooth.

4. Install the magnetic pickup in the flywheel housing. Turn the magnetic pickup clockwise until the magnet contacts a tooth of the flywheel ring gear.

5. Turn the magnetic pickup counterclockwise for 1 1/4 turns (450 degrees). Maintain a clearance of 1.41 to 1.76 mm (.0555 to .0693 inch) between the magnetic pickup and the tooth of the flywheel ring gear. Tighten the locknut to 45 ± 7 N·m (33 ± 5 lb ft).