In the old days, engines used various methods to start up. These ranged from human-powered techniques like a removable crank handle to gun powder cylinders. They proved to be inconvenient and dangerous--however, an engine's behavior was unpredictable during starting which led to near-fatal injuries. The development of larger engines with higher compression ratios paved the way for the modern self-starter motor.
If you're in the market for a starter motor, this guide will help you understand and choose the right part for your vehicle.
How does a starter motor work?
A starter motor converts electrical energy from the vehicle's batteries into mechanical energy--giving life to the engine. At zero RPM, an internal combustion engine is unable to produce torque and the starter helps turn it over. By providing rotational speed or RPM to an engine's crankshaft--the combustion process starts and the engine can now power itself. As the engine spins faster than the starter, the bendix drive (an over-running clutch device) automatically disengages the starter gear from the engine gear. The starter motor was designed to make sure that anyone can run an internal combustion engine with ease.
What are the different types of starter motors?
Pneumatic --- It's reliable, mechanically simple, and delivers a higher torque. Used by some gas turbine and diesel engines, it has a geared turbine, pressure tank, and an air compressor. The turbine spins after compressed air is released from its tank. As the engine runs, its pressure tank is recharged by the compressor. A pneumatic starter is used by trucks and earth-moving equipment.
Gear-reduction --- Designed with a direct-drive and movable pole shoe--it's mainly used for cost-reduction rather than electrical or mechanical benefits. The solenoid was removed, replaced by a separate relay starter, and movable pole shoe. Due to its larger size, higher current requirements, and heavier weight, the gear-reduction starter motor is almost obsolete.
Electric --- It's the most common type used on modern gasoline or diesel engines, and a solenoid switch is mounted on the starter. A key-operated switch activates the battery which sends a low-current power to the solenoid. The solenoid pushes the drive pinion on the starter drive shaft and meshes with the ring gear, on the engine's flywheel. High-current contacts are closed by the solenoid and the engine starts running. The starter motor's pinion gear is controlled by a bendix drive--a device which allows the pinion gear to engage or disengage the engine's flywheel automatically when the engine fires or the starter is powered.
What should I look for in a starter motor?
Check your vehicle's manual for the starter motor's model or part number. It's important that you get the correct type and make to avoid any problems. After replacing your vehicle's starter motor, it's better to send the broke unit to the parts store. It will be rebuilt and sold as refurbished units. If you have the knack for rebuilding things, you can purchase a starter motor repair kit. It will save you money and learn more about repairing as well.
Finding the right replacement part for your vehicle is very important. Ask, shop or even do your own research for brands that offer the best quality and deals. Don't forget to always check your vehicle's wiring. Dirty or faulty wiring can cause electrical problems which leads to a dead starter motor. A simple cleaning and repair can save you a lot of money.