Starter bolt issues (again)

[Sganderson]

Hello all,
I know this subject has been beat to death in this forum. This is the third time in 4 or five months I’ve had to drill out a starter bolt. Last time this happened I added the correct starter bracket that It did not have when I bought it. Also put gm starter bolts # 15544950. Both of which this forum helped me find and I’m very thankful for. All seemed to be going well for the past two months daily driven until This morning another one snapped (25 degrees f outside) The only other thing I can imagine doing to prevent this is installing a block heater for cold mornings . Any ideas?

 

[Sganderson]

I ask this because I haven’t seen a thread about this when correct bolts and correct bracket was applied .

 

[cucvrus]

You will need to check the depth of the starter gear engagement. The depth of the gear into the flex-plate. It is possible you have a deep engagement and it is forcing the starter to rock back and forth. Do you have any milling of the flex-plate teeth? If you have a bad spot the starter must stay engaged and ride the humps out and this will stress the starter bolts regardless if you have the bracket in place. You may need to put a shim or 2 in place on the starter mounting surface to the block. I have seen this a few times. Not common but possible. Good Luck. I know it stinks but if you continue to run it uncorrected the issue will just get worse.

 

[Sganderson]

You will need to check the depth of the starter gear engagement. The depth of the gear into the flex-plate. It is possible you have a deep engagement and it is forcing the starter to rock back and forth. Do you have any milling of the flex-plate teeth? If you have a bad spot the starter must stay engaged and ride the humps out and this will stress the starter bolts regardless if you have the bracket in place. You may need to put a shim or 2 in place on the starter mounting surface to the block. I have seen this a few times. Not common but possible. Good Luck. I know it stinks but if you continue to run it uncorrected the issue will just get worse.

Thanks, that’s the lead I was looking for. I have wondered in the past if the starter was “too close” to the flywheel and thus causing stress on the bolts.

 

[Greasy]

Are new GM starter bolts “good” and new ARP starter bolts “better”? I am wanting to switch mine out to prevent a future problem. My plan is to replace the existing bolts and torque the new bolts to factory spec.

 

[cucvrus]

Are new GM starter bolts “good” and new ARP starter bolts “better”? I am wanting to switch mine out to prevent a future problem. My plan is to replace the existing bolts and torque the new bolts to factory spec.

I have never seen any difference in any starter bolts. I buy M10 starter bolts and they are from a local supplier. I never had many issues with good batteries and the starter properly shimmed or un shimmed. Making sure you have it attached at the front brace and no teeth are chewed out is also key to good starter life. Just keep in mind 1 area of chewed teeth leads to uneven engagement and outward pressure being pushed outward onto the starter. If you have a flex=-plate that occasionally gives a ZING when you attempt to start it you have problems and they are only going to get worse. Fix it now. Or NOT. Good Luck.

 

[Keith_J]

Flex plate run out can over stress bolts. Stretches them, then they are loose and soon to fail. Check bolt torque a week after install. If loose, you need shimming. If the bolts are ever found loose, Check clearance and always replace the bolts.

Check ring gear to pinion clearance on a full engine revolution. Worn main bearings can also cause problems. Check running oil pressure.

 

[Mullaney]

Hello all,
I know this subject has been beat to death in this forum. This is the third time in 4 or five months I’ve had to drill out a starter bolt. Last time this happened I added the correct starter bracket that It did not have when I bought it. Also put gm starter bolts # 15544950. Both of which this forum helped me find and I’m very thankful for. All seemed to be going well for the past two months daily driven until This morning another one snapped (25 degrees f outside) The only other thing I can imagine doing to prevent this is installing a block heater for cold mornings . Any ideas?

You have already mentioned "Genuine GM Starter Bolts". There are also a set of shims that go on those starters too that most folks cast off as garbage. I remember discovering how that worked as I cracked my first cast aluminum "nose" on a starter long years ago. There are shims for the nose on the front of the starter too.



It might take you an hour or more to shim up that starter correctly. Two measurements: One up and down and the Second into the ring gear on the flywheel. Need to be able to look up into that dark hole to look carefully at how the starter gear engages. I have wedged the bendix drive forward with wood to "see" what is going on up there.

Over the years of trying to hotrod assorted Chevrolet engines, I learned more and even used an old school system called Prussian Blue (NAPA has it). Web search it. It is a neat tool to get the starter gear depth set. Easy to work with too.

TM

 

[Sganderson]

You have already mentioned "Genuine GM Starter Bolts". There are also a set of shims that go on those starters too that most folks cast off as garbage. I remember discovering how that worked as I cracked my first cast aluminum "nose" on a starter long years ago. There are shims for the nose on the front of the starter too.

View attachment 824953

It might take you an hour or more to shim up that starter correctly. Two measurements: One up and down and the Second into the ring gear on the flywheel. Need to be able to look up into that dark hole to look carefully at how the starter gear engages. I have wedged the bendix drive forward with wood to "see" what is going on up there.

Over the years of trying to hotrod assorted Chevrolet engines, I learned more and even used an old school system called Prussian Blue (NAPA has it). Web search it. It is a neat tool to get the starter gear depth set. Easy to work with too.

TM

I had no idea there were shims for the nose of the starter

 

[Mullaney]

I had no idea there were shims for the nose of the starter

Me either until I learned the hard way. Long years ago.
Sure that will help you solve your problem...

It is a real PITA to deal with for sure!
.

 

[Sganderson]

I worked on it tonight for a couple hours, extracted the broken bolt and tried to measure clearance... I really couldn’t see. I went ahead and added two shims thinking if it was too much I could easily take one out. So I started with 1/32 shim now at 3/32. Installed starter with new bolts and bracket and fired her up. All seemed well , may even have spun a little faster. Did that a few times. So I guess for now we will see. Thank you all.

If this fails I’ll post again with nothing but expletives . You all will know what happened lol.

 

[TedO]

Hello all,
I know this subject has been beat to death in this forum. This is the third time in 4 or five months I’ve had to drill out a starter bolt. Last time this happened I added the correct starter bracket that It did not have when I bought it. Also put gm starter bolts # 15544950. Both of which this forum helped me find and I’m very thankful for. All seemed to be going well for the past two months daily driven until This morning another one snapped (25 degrees f outside) The only other thing I can imagine doing to prevent this is installing a block heater for cold mornings . Any ideas?

I was having this problem until I removed the flywheel cover panel (next to starter) before bolting the starter on. I think it was preventing the starter from mating flush. Havent had an issue for a couple of years.

 

[frank8003]

I worked on it tonight for a couple hours, extracted the broken bolt and tried to measure clearance... I really couldn’t see. I went ahead and added two shims thinking if it was too much I could easily take one out. So I started with 1/32 shim now at 3/32. Installed starter with new bolts and bracket and fired her up. All seemed well , may even have spun a little faster. Did that a few times. So I guess for now we will see. Thank you all.

If this fails I’ll post again with nothing but expletives . You all will know what happened lol.

Expletive deleted for future