Starting System: Description
The Delco-Remy starter is part of the cranking circuit, which also consists of the battery, ignition switch and related wiring. See Fig 1. When the ignition switch is turned to the START position, the starter solenoid windings are energized. This causes the solenoid plunger to move the shift lever, which engages the pinion with the engine flywheel ring gear. The movement of the plunger also closes the main solenoid contacts, applying battery voltage to the starter motor.
When the engine starts, the pinion will overrun, protecting the armature from excessive speed and the flywheel from damage. When the ignition switch is released, the plunger return spring disengages the pinion.
On starters with the SD designation, the pinion is driven directly by the armature shaft. Wound field coils energize pole pieces that are arranged around the armature. These are used on gasoline engines. Starters designated with PG have a pinion that is driven by a gear reduction system. These starters are used on diesel or large displacement gasoline engines. The PG260 starter should not be dissembled for any reason and is serviceable only by complete replacement. The 28MT starter is used on diesel truck engines and is a gear reduction starter with an overrunning roller type clutch and enclosed shift lever.