1966 Ford Mustang engine starter motor

REDDOG1

MEMBER
1966 FORD MUSTANG
V8
2WD
AUTOMATIC
68,000 MILES

I purchased a mustang that was in pieces but the engine /transmission were already assembled, when I got it running the starter motor banged hard like it was hit with a hammer the engine fired up alright and I restarted it a couple of more times with the same bang from the starter motor. I removed the starter and inspected the bendix and discovered that three of the teeth had been chipped, inspection of the flywheel showed the same damage on the flywheel with 8 or 9 teeth that were also chipped. What could be the problem?

3 Replies

MHPAUTOS

MECHANIC
31,937 POSTS

You will have to replace the starter and the drive plate and check starter clearance, this may have been old damage not repaired by the previous owner.

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Sunday, December 21st, 2014 AT 12:31 PM

REDDOG1

MEMBER
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Reddog1 here, I measured the distance between the flywheel and the bell housing plate which was 5/8th of an inch, I also measured the distance between the bendix in the relaxed position and fully engaged ( all the way forward to the stop) and it was also 5/8th of an inch." No gap". If the bendix did not retract immediately and didn't clear the flywheel before the engine gained RPM would the flywheel force it back with the resounding bang which was heard? The starter motor was rebuilt by a very reputable business and they knew that it was for a 289 V8 could there be a flywheel with more than 157 teeth that did not match the teeth on the bendix?

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Sunday, December 21st, 2014 AT 2:53 PM

CJ MEDEVAC

MECHANIC
11,005 POSTS

DIFFERENT FELLER

I LOOKED AT 3 ONLINE PARTS STORES, 157 TOOTH SEEMS TO BE THE NORM ON A 289

MAYBE MR. STARTER MIGHT HAVE THE WRONG TEETH OR BE THE WRONG STARTER?

RAN INTO THAT ON MY DAD'S '76 F-150, SOMEONE JUST SLAPPED ON ANOTHER FROM ANOTHER FORD. MANY FORD'S WILL "FIT" THE HOLE, THROW AND TOOTH COUNT MAY BE WRONG, BUT STILL SORTA WORK FOR A WHILE. 'TIL THINGS CHEW A WHILE

WHEN HE GOT A REPLACEMENT, THE STORE DECIDED THE "CORRECT ONE" WAS NOT A MATCH TO THE (WRONG) OLD ONE. SO THEY COMPENSATED (WRONG THING TO DO)

IT TOOK ME 3 MINUTES TO INSTALL IT, UPON STARTING, IT TOOK ONLY A MILLISECOND TO BUST OFF BOTH EARS, AND LEFT IT A DANGLING BY THE CABLE!

NOT SAYING THIS IS YOUR CASE, BUT MAYBE WORTH COMPARING IT TO ONE AT A PARTS STORE

THE "BANG" MAY ALSO HAVE BEEN THE FLYWHEEL ROTATION SUDDENLY HITTING THE GAP IN THE TEETH, AND SLAMMING INTO THE NEXT BETTER TEETH

OR, AS THE STARTER'S TEETH WERE RETRACTING NICE AND SMOOTHLY, STILL MESHING SMOOTHLY WITH GOOD FLYWHEEL TEETH ON IT'S WAY OUT. BOOM. HERE COMES THE GAP TO INTERRUPT THE FLOW OF THINGS!

MY '46 WILLYS JEEP STARTER RELIES ON A LARGE ECCENTRIC WASHER (SORTA OFF CENTERED ON THE STARTER SHAFT) TO "WEIGHT" THE STARTER DRIVE SO THAT WHEN I HIT "START" IT MOMENTARILY HOLDS IT STILL WHILE THE STARTER SHAFT SORTA "SCREWS" THE TEETH INTO THE FLYWHEEL, ONCE IN THERE, IT'S AT THE END OF "SCREW TRAVEL" AND IT BEGINS TO ROTATE THE FLYWHEEL

WHEN IT CRANKS UP, AND I RELEASE THE KEY, THE FLYWHEEL TOOTH ENGAGEMENT WITH THE STARTERS TEETH "UNSCREWS" THE STARTER DRIVE BACK INTO THE STARTER. A VERY LIGHT SPRING ON THE STARTER DRIVE HOLDS IT FROM "FLOPPING" BACK INTO THE FLYWHEEL TEETH (THIS SPRING IS SO LIGHT, IT DOES NOT SHOVE IT BACK OUT OF THE FLYWHEEL, WHEN CRANKED UP)

THE MORAL OF THAT STORY IS

IT IS NORMAL FOR TEETH TO STILL "MESH" (FOR MOMENTS) WHEN IT'S CRANKED UP, AND STARTER IS IN THE DISENGAGEMENT PROCESS. IT'S NOT A "SLAM IN" AND "JERK OUT" KINDA THING, BEFORE THE TEETH CAN CATCH THE NEXT TOOTH!

OUR OTHER "DEFAULT STARTER" IS FOOLPROOF, AND WILL NEVER BREAK, AS DEMONSTRATED BY MY DAUGHTER WHEN SHE WAS 10!

THE MEDIC

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