Originally Posted by Rosewood
350 chevy with new battery and rebuilt starter that is probably a year old. With the new battery the starter turns normal speed for 4 or 5 cranks then drags bad and drains the battery. Normally I would be looking for a grounding problem but am I correct that bad grounding could not drain a battery like that, just make the starter drag. So, if that's true then it must be a bad starter, right?
Rebuilt starters are notoriously bad and the thing probably needs to be replaced again. It sounds like something; field or rotor coils are shorting as they warm up with the high amperage that flows thru starters. Of it could be a bad brush or its holder letting a brush get sideways furnishing current to a rotor coil not yet in magnetic position to the field resulting in oposition force against rotation.
It could also be a bad solenoid, these have contacts that switch the high current load the starter uses, the coil that activates the contactor or the contacts themselves could be suffering a heat related failure and loosing contact as they get hot.
Could also be the starter isn't sufficiently mounted and is binding against the gear.
1) This can range from the solenoid not doing its other function of holding the starter pinion gear in the ring gear.
2) The starter not shimmed enough to provide the .050 inch tooth clearance between the root of the ring teeth and the crown of the pinion.
3) Or the starter is not held tightly enough so that it can't try to twist out under the cranking load.
3.A) This can be incorrect on insufficiently tight starter mounting bolts.
3.B) A crack in the block casting where the these bolts attach.
3.C) Or the torque reaction plate between the back of the starter motor and the block is loose or missing.
Then of course there are the electrical problems ranging from wiring, to the failure actually being inside the battery when a high amperage drain is placed on it, that can be tested for a battery dealer with a load machine to simulate high amp draws.