When you beat on your starter
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Joined: Mar 2004
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From: St louis
When you beat on your starter
what are you doing to make it work? Is it the brushes not making contact or the solenoid contacts? When you hit start and hear a loud clack, but no crankee, is that the contacts making and the motor isn't turning because of the brushes not making contact? Can you buy brushes for this? (1981)
My friend's 2nd gen NA starter did that so often that he had to carry a plastic hammer under the seat. A tap or two every now and then was all it took. Then it eventually stopped having the problem. We think once it was used more often, whatever was blocking the electrical contact got worn away.
84SE-EGI helpy-helperton
Joined: Oct 2002
Posts: 3,584
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From: Phoenix, AZ
Usually, when the 'technical tap' fixes a starter issue, it has to do with poor contact between the positive lead going from the solenoid to the starter motor brushes.
Here's how this works; on the SA and FB starters, the solenoid is 'switched' to carry the current for 1) pushing the starter pinion gear into the flywheel ring gear and turning the eccentric shaft, and 2) powering the starter motor, itself.
When you hit 'START' on the ignition switch, the current from the battery flows through the ignition lead, powers up the inductance coil on the solenoid, and causes a lever to push the pinion gear into the flywheel ring gear teeth. As soon as the pinion gear hits it's full extension as judged by the solenoid electrode, current is carried through to the motor brushes, causing the starter motor to spin. As it spins the pinion, it turns the flywheel and rotates the engine.
This arrangement allows for the starter motor to NOT be engaged UNTIL the pinion gear is seated, dramatically reducing undue wear on the starter motor, pinion gear teeth, and ring gear teeth.
When the contacts on the starter solenoid poles get dirty or corroded, this can lead to an intermittent connection whereby the current won't trip the solenoid field (whirrrring starter motor, but no 'clack' engaging the pinion), or a the solenoid firing, but not powering the starter motor (clack but no whirrrr). Another potential cause could be the brushes in the starter motor getting carboned up or otherwise stuck - this would be pretty rare, however, since they are spring-assisted to push against the commutator.
HTH,
Here's how this works; on the SA and FB starters, the solenoid is 'switched' to carry the current for 1) pushing the starter pinion gear into the flywheel ring gear and turning the eccentric shaft, and 2) powering the starter motor, itself.
When you hit 'START' on the ignition switch, the current from the battery flows through the ignition lead, powers up the inductance coil on the solenoid, and causes a lever to push the pinion gear into the flywheel ring gear teeth. As soon as the pinion gear hits it's full extension as judged by the solenoid electrode, current is carried through to the motor brushes, causing the starter motor to spin. As it spins the pinion, it turns the flywheel and rotates the engine.
This arrangement allows for the starter motor to NOT be engaged UNTIL the pinion gear is seated, dramatically reducing undue wear on the starter motor, pinion gear teeth, and ring gear teeth.
When the contacts on the starter solenoid poles get dirty or corroded, this can lead to an intermittent connection whereby the current won't trip the solenoid field (whirrrring starter motor, but no 'clack' engaging the pinion), or a the solenoid firing, but not powering the starter motor (clack but no whirrrr). Another potential cause could be the brushes in the starter motor getting carboned up or otherwise stuck - this would be pretty rare, however, since they are spring-assisted to push against the commutator.
HTH,
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