Quote:
packardguy53 wrote:
" "My question, is how does the starter disengage"
I'm not sure I'll say this properly, but, when the engine starts to run, the bendix in the starter is kicked back automatically to disengage the ring-gear. Any changes or additions to this descriptions are welcome.
Hope this helps.
Steve
That is correct. The conventional Bendix is an assembly which rides in a spiral groove on the motor shaft. When the motor starts turning, the Bendix not being attached to the shaft is stationary due to its heavy mass. Effectively when the shaft starts rotating it "screws" the Bendix assy out to the end of the groove to engage the flywheel. When the engine starts, the flywheel teeth start moving and begins turning the Bendix backwards faster than the motor which "unscrews" the assembly back in to the starting point of the groove. At the same time the engine starts, the driver lets off the starter so the motor stops turning and Bendix stays in the park position as everything winds down. A small detent helps to keep the Bendix from vibrating out.
The problem with the conventional Bendix was if the engine gave a false start it would tend to kick the Bendix and start to disengage the starter. On the times this happened it caused frustration and in some cases damage to the teeth as the flywheel and starter clashed. Packard started using an anti-kickback unit in the early 50s and made the assy available to several earlier years. That Bendix is like a conventional unit but with an extra spring loaded pin which drops into a hole at the end of the shaft groove when the Bendix reaches the end of travel and engages the flywheel. In order to disengage the pin the engine has to be running and able to consistently spin the Bendix backward. The centrifugal force of the spinning causes the pin to push against the spring and raise out of the hole. The backward rotation and disengagement is then like the conventional unit. If the engine made a false start the short burst of centrifugal force is generally not enough to disengage the pin so the pinion stayed engaged with the flywheel.
Downside to the anti-kickback is if you engage the starter and for some reason the engine does not start the pin can keep the Bendix engaged with the flywheel because there is no centrifugal force to release the pin. In some situations it is necessary to remove the starter and manually repark the Bendix to unjam things. During bench testing you also need to make sure to return the Bendix to the park position before mounting the starter on the car.
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