starter gremlins

[Zef]

My baby is stored for the winter...so goes the projects. Last summer I got some problems with my starter. 3 times on 10 it won't engage the ring gear....it always crank without hesitation...so not an electrical problem....I removed it...the pinion is in good shape...I gave a look at the ring gear looking for damaged or missing teeth...none. My question is : Is it the solenoid or the bendix that do the job of pushing the pinion to engage the ring gear ? which one is faulty......Thanks...Syl

[911pcars]

Originally posted by zefsuper911
My baby is stored for the winter...so goes the projects. Last summer I got some problems with my starter. 3 times on 10 it won't engage the ring gear....it always crank without hesitation...so not an electrical problem....I removed it...the pinion is in good shape...I gave a look at the ring gear looking for damaged or missing teeth...none.

My question is : Is it the solenoid or the bendix that do the job of pushing the pinion to engage the ring gear ? which one is faulty......Thanks...Syl

When the solenoid energizes, it connects the circuit between the battery and the starter motor. At the same time, it uses electro-magnetism to push the pinion gear (on the armature shaft) into mesh with the ring gear via linkage. The pinion gear contains an overrunning clutch that allows the starter motor to drive the pinion gear in one direction only. When the engine starts, the faster rotating ring gear (and engine) wants to drive the pinion gear (not good if successful). The one-way clutch and the solenoid linkage return spring allows the pinon gear to retract.

A "Bendix" drive is another type of pinion gear mechanism that uses inertia to engage and disengage the pinion gear w/the ring gear (not used on Porsches). The solenoid in these systems is merely used as a heavy duty relay to connect battery to starter motor.

If the starter motor is rotating, it sounds like the overrunning clutch is intermittently slipping. Either that or your ring gear might be missing some teeth. You checked the ring gear so it's probably the former.

Hope this helps,
Sherwood

[Zef]

Thanks a lot for lightened me on that Sherwood. I'm now more equipped to bring that starter at the small shop that overhaul them...