brianbajnauth

So lately the car start up and the starter keeps on spinning. I replaced one started due to it burning out while keeping spinning. This is a starter from sutozone. Could it be possible that two starters could be bad? Seems to only do it on cold starts also not so much when hot. What do you guys think

cookseyb

Bad Bendix, try a little lubricant on the shaft..

brianbajnauth

Could it be that it needs to be shimmed a little?

cookseyb

Shimming only affects the tooth engagement. If the Bendix doesn't return the starter won't stop spinning.

1 FMF

iTrader: (1)

what make/model/year of car/engine?
is it an automatic or manual transmission, and has the flexplate or flywheel ever been changed?

chevy has used a 153 tooth or a 168 tooth ring gear count on the flexplate/flywheel,
and that corresponds to a 9 or 11 tooth gear count on the starter pinion. The LS1 has a 168 tooth flywheel.

153 tooth flexplate/flywheel = 11 tooth starter
168 tooth flexplate/flywheel = 9 tooth starter

you may have gotten a starter with 11 pinion teeth and is binding under load when cranking the engine. some starters with 11 pinion teeth, if the pinion is ground a certainly way will work, sometimes not.
the fact the starter pinion is sticking into the flexplate/flywheel teeth will keep the solenoid on the starter engaged, keeping the starter spinning while the engine is running after your ignition key is no longer sending power to it.

technically it's not a bendix. it's a little plastic shift fork in there. the solenoid plunger on top of starter is 2 function - extend the pinion out to engage the flexplate and make the electrical contact from the hot battery cable connected to it to the starter motor.
but technically you are correct when the solenoid plunger isn't allowed to return to it's original position under it's own spring power, it keeps making the electrical contact sending power to the starter keeping the starter spinning and burning out... due to the pinion stuck to the flexplate teeth... due to the mechanics of the shift fork inside the starter.

speedydeedy

Yes. If it is too tight it will not disengage.

JakeRobb

Sorry for the thread resurrect -- I find myself in the same situation. I have a 2002 Z28 into which I have just installed an LS3, and today I turned the key for the first time. I have the fuel pump disconnected, and my intent was only to blip the starter a tiny bit to confirm a healthy circuit, but the starter cranked and wouldn't stop -- even after I turned the key off and removed it. The only thing that would stop it was disconnecting the battery. The car has a 168-tooth ACT flywheel which I used successfully with my stock LS1 starter. The new starter is a Bosch SR8581N. I pulled it off and counted; 11 teeth. This is somewhat frustrating; I’ve read every bit of LS swap advice i could find for close to twenty years, and have never come across this particular nugget. I’m thinking when all is said and done with my install, I might try to create a web repository of exactly this sort of info.

Anyway, I assume I just need to add some shims, but I can't seem to find any for LS motors. I'd love a link to the right thing to buy, if anyone has one.

EDIT: I think I found it something that will work:

wannafbody

iTrader: (2)

Not sure specifically about your ACT flywheel but a stock flywheel will work with the 9 tooth 5.3 starter. You can call ACT and ask.

JakeRobb

I’m a little worried that shimming the starter is going to make the gears mesh tighter rather than looser. 🤔

The starter is above the center of the flywheel, and shims will push it downward — closer to the center, and therefore tighter. But maybe I’m missing something here?

JakeRobb

I’m pleased to report than the shims in the PowerMaster kit did the trick! My mental image of where the starter pinion meets the flywheel was off, and moving the starter down actually does add space.

They were incredibly difficult to install without removing the headers, but I got it done.