The Ford Barn

mralternator · 08-24-2013, 02:14 PM

Cranking with Higher Voltage—We said earlier that a starter cannot create enough force on its own to break a housing . We should have clarified that this is true only if it is being used with the voltage for which it was designed. There are still people out there who believe that it is okay to double the voltage to a starter without damaging anything—6 volts to 12 volts or 12 volts to 24 volts. When you double the voltage without changing the resistance in the starter, you will cause amperage to double at the same time. Power is equal to voltage multiplied by amperage, so you will be quadrupling the power of the starter if you double the voltage. To put this into perspective, a 1kW starter suddenly has the torque of a 4kW starter.
Failed Start—Whenever an engine is cranked and fails to start, the engine will stop near the top of a compression stroke, but it does not sit there long. Usually, it will roll back slightly to relieve pressure in the cylinder. That reverse motion of the crankshaft may take several seconds and be unnoticeable. If the operator is in a hurry and attempts to re-engage the engine during that roll-back, a head-on collision between the ring gear and the starter drive takes place. This probably accounts for more damaged starters than any other cause. Delco-Remy put out a service bulletin explaining it in 1955 . They obviously saw it as a problem then, as it still is today.
Starting Fluids—The use of ether or other starting fluids can cause detonation if used in diesel applications unless the manufacturer prescribes it. This untimely explosion can break housings, pinion gears and even armature shafts .
Ignition Timing—Kick-back while cranking can be caused by an ignition timing problem and can result in a broken starter housing. On an older vehicle with a distributor, this could be caused by a cracked distributor cap or faulty plug wires. On new engines, defective crank position sensors can result in kick-back during cranking.
Ring-Gear-to-Pinion-Clearance—Incorrect clearance between the pinion and ring gear can break a housing, too. If clearance is insufficient, and the teeth bottom out, you can easily get enough lateral pressure to crack a housing. Examine the pinion closely for signs of too little clearance. This was once a common problem with GM pad-mount starters , but it can also happen on Fords, if the bell-housing cover plate that locates a Ford starter is damaged. Engine, transmission and flywheel swaps are the primary cause of improper clearance. Above all, pinion clearance must be measured when this is suspected. Listening to a few starts is not a substitute for taking a measurement. Shims can be added to GM pad-mount starters to increase pinion clearance.

08-24-2013, 02:14 PM	#17
mralternator BANNED Join Date: Aug 2013 Location: Rolesville NC Posts: 91	Re: Starter Hung Up Cranking with Higher Voltage—We said earlier that a starter cannot create enough force on its own to break a housing . We should have clarified that this is true only if it is being used with the voltage for which it was designed. There are still people out there who believe that it is okay to double the voltage to a starter without damaging anything—6 volts to 12 volts or 12 volts to 24 volts. When you double the voltage without changing the resistance in the starter, you will cause amperage to double at the same time. Power is equal to voltage multiplied by amperage, so you will be quadrupling the power of the starter if you double the voltage. To put this into perspective, a 1kW starter suddenly has the torque of a 4kW starter. Failed Start—Whenever an engine is cranked and fails to start, the engine will stop near the top of a compression stroke, but it does not sit there long. Usually, it will roll back slightly to relieve pressure in the cylinder. That reverse motion of the crankshaft may take several seconds and be unnoticeable. If the operator is in a hurry and attempts to re-engage the engine during that roll-back, a head-on collision between the ring gear and the starter drive takes place. This probably accounts for more damaged starters than any other cause. Delco-Remy put out a service bulletin explaining it in 1955 . They obviously saw it as a problem then, as it still is today. Starting Fluids—The use of ether or other starting fluids can cause detonation if used in diesel applications unless the manufacturer prescribes it. This untimely explosion can break housings, pinion gears and even armature shafts . Ignition Timing—Kick-back while cranking can be caused by an ignition timing problem and can result in a broken starter housing. On an older vehicle with a distributor, this could be caused by a cracked distributor cap or faulty plug wires. On new engines, defective crank position sensors can result in kick-back during cranking. Ring-Gear-to-Pinion-Clearance—Incorrect clearance between the pinion and ring gear can break a housing, too. If clearance is insufficient, and the teeth bottom out, you can easily get enough lateral pressure to crack a housing. Examine the pinion closely for signs of too little clearance. This was once a common problem with GM pad-mount starters , but it can also happen on Fords, if the bell-housing cover plate that locates a Ford starter is damaged. Engine, transmission and flywheel swaps are the primary cause of improper clearance. Above all, pinion clearance must be measured when this is suspected. Listening to a few starts is not a substitute for taking a measurement. Shims can be added to GM pad-mount starters to increase pinion clearance.