Broken Starter Bolt
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Joined: Nov 2011
Posts: 181
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From: Franklin Square NY
Broken Starter Bolt
So, I did what other forum members said and changed the original starter out of my C5 Corvette.
Snapped the bolt on the outside (the piece that breaks if the starter mount breaks)
Tried easy outs and than I was like, yea I'm done with this. Drill right through it. Now I am trying to figure out what tap do drill bit do I need for a 7/16th bolt.
Currently the hole is around 27/64ths What tap should I use? I was hoping to get a 7/16ths in there but I think I might be stuck with a 1/2inch.
Snapped the bolt on the outside (the piece that breaks if the starter mount breaks)
Tried easy outs and than I was like, yea I'm done with this. Drill right through it. Now I am trying to figure out what tap do drill bit do I need for a 7/16th bolt.
Currently the hole is around 27/64ths What tap should I use? I was hoping to get a 7/16ths in there but I think I might be stuck with a 1/2inch.
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Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
So, I did what other forum members said and changed the original starter out of my C5 Corvette.
Snapped the bolt on the outside (the piece that breaks if the starter mount breaks)
Tried easy outs and than I was like, yea I'm done with this. Drill right through it. Now I am trying to figure out what tap do drill bit do I need for a 7/16th bolt.
Currently the hole is around 27/64ths What tap should I use? I was hoping to get a 7/16ths in there but I think I might be stuck with a 1/2inch.
Snapped the bolt on the outside (the piece that breaks if the starter mount breaks)
Tried easy outs and than I was like, yea I'm done with this. Drill right through it. Now I am trying to figure out what tap do drill bit do I need for a 7/16th bolt.
Currently the hole is around 27/64ths What tap should I use? I was hoping to get a 7/16ths in there but I think I might be stuck with a 1/2inch.
I had to weld the broken part back on.and it turned out excellent.
If you drill out the hole for a bigger bolt, you will weaken the mount. If you have to drill it out, insert a helicoil.
I would use some heat and try to get the broken part out of the OEM drilled and tapped hole.
Bill
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Instructor
Joined: Nov 2011
Posts: 181
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From: Franklin Square NY
The starter boss (mount ) is extremely fragile and will break easily. The outside hole is POORLY DESIGNED! Ask me how I know???
I had to weld the broken part back on.and it turned out excellent.
If you drill out the hole for a bigger bolt, you will weaken the mount. If you have to drill it out, insert a helicoil.
I would use some heat and try to get the broken part out of the OEM drilled and tapped hole.
Bill
I had to weld the broken part back on.and it turned out excellent.
If you drill out the hole for a bigger bolt, you will weaken the mount. If you have to drill it out, insert a helicoil.
I would use some heat and try to get the broken part out of the OEM drilled and tapped hole.
Bill
Safety Car
Joined: Dec 2010
Posts: 3,938
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From: Fords, NJ
Did you have an issue with the starter the made you change it out?
Reason I ask is...IF there was an issue then granted it needed to be changed BUT if there was nothing wrong with it then you should have left it alone... This quote is from Paul Koerner, GM World Class Certified Service Technician......"First, the fact that the short/long bolt starter is any less reliable is garbage. There is not one documented test that there has ever been an issue.
Second, the starter is a simple one, use the one out of the trucks.
Fact is, unless there is actual internal engine binding, there is ONLY ONE THING that caused a broken snout on a starter. INCORRECT INSTALLATION OF STARTER!
People do not torque the fasteners correctly, or dont use the correct bolts or attempt to use shims where SHIMS SHOULD NEVER be used.
Why you would change the starter if its not giving you an issue????
Maybe if the engine is heavily modified with higher compression, I can see that.
Starter bolt torque is 37 ft lbs. If you over torque the fasteners, you will distort the snout. If you use the incorrect bolts, you will misalign the starter to the block and THEN you can damage the block.
12592294 is the starter for the 5.3 LM7 truck engine that will work with 2 equal length bolts.
But as I said in the beginning, only MISINSTALLATION or internal engine binding can create this type of failure.
Allthebest, Paul"
When questioned on the life of a starter he had this to say: "There are a few factors to starter life.
#1, exposure to heat, especially if you have headers, which you note you do not. I usually install the shield for the solenoid from the trucks just to give me a bit of extra insurance for my customers for longevity.
#2, correct torque on both starter bolts to block at 37 ft lbs and the battery positive cable terminal at 11 ft lbs and the S terminal at 37 INCH LBS.
#3, modifications hurt starters, higher compression, superchargers and the like put strain on the snouts of those starters.
#4, storage conditions meaning oxidation of key electrical connections like the battery, engine grounds, starter mounting locations and other factors.
Personally, I have seen starters die after 4 years, I have seen others last the life of the vehicle.
You conditions may vary this but the biggest single factor is INSTALLATION. if you havent had a problem, chances are, your not going to.
Allthebest, Paul"
I know this probably has nothing to do with your broken bolt but the point I'm trying to make here is if it's not broke, there's no need to fix it.
My 04 still has it's original starter. I'll worry about replacing it when it either craps out or I get hydro lock because of a leaking head gasket and it breaks !
Reason I ask is...IF there was an issue then granted it needed to be changed BUT if there was nothing wrong with it then you should have left it alone... This quote is from Paul Koerner, GM World Class Certified Service Technician......"First, the fact that the short/long bolt starter is any less reliable is garbage. There is not one documented test that there has ever been an issue.
Second, the starter is a simple one, use the one out of the trucks.
Fact is, unless there is actual internal engine binding, there is ONLY ONE THING that caused a broken snout on a starter. INCORRECT INSTALLATION OF STARTER!
People do not torque the fasteners correctly, or dont use the correct bolts or attempt to use shims where SHIMS SHOULD NEVER be used.
Why you would change the starter if its not giving you an issue????
Maybe if the engine is heavily modified with higher compression, I can see that.
Starter bolt torque is 37 ft lbs. If you over torque the fasteners, you will distort the snout. If you use the incorrect bolts, you will misalign the starter to the block and THEN you can damage the block.
12592294 is the starter for the 5.3 LM7 truck engine that will work with 2 equal length bolts.
But as I said in the beginning, only MISINSTALLATION or internal engine binding can create this type of failure.
Allthebest, Paul"
When questioned on the life of a starter he had this to say: "There are a few factors to starter life.
#1, exposure to heat, especially if you have headers, which you note you do not. I usually install the shield for the solenoid from the trucks just to give me a bit of extra insurance for my customers for longevity.
#2, correct torque on both starter bolts to block at 37 ft lbs and the battery positive cable terminal at 11 ft lbs and the S terminal at 37 INCH LBS.
#3, modifications hurt starters, higher compression, superchargers and the like put strain on the snouts of those starters.
#4, storage conditions meaning oxidation of key electrical connections like the battery, engine grounds, starter mounting locations and other factors.
Personally, I have seen starters die after 4 years, I have seen others last the life of the vehicle.
You conditions may vary this but the biggest single factor is INSTALLATION. if you havent had a problem, chances are, your not going to.
Allthebest, Paul"
I know this probably has nothing to do with your broken bolt but the point I'm trying to make here is if it's not broke, there's no need to fix it.
My 04 still has it's original starter. I'll worry about replacing it when it either craps out or I get hydro lock because of a leaking head gasket and it breaks !
Last edited by SG Lou; Aug 29, 2014 at 11:32 PM.
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Joined: Nov 2011
Posts: 181
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From: Franklin Square NY
Than I pretty much listen to information on this forum and ****ed myself, thanks. I went outside to check and see how big I drilled the hole out. If the 7/16 taps work I will be shocked. I might need to drill it out even bigger to more than likely 1/2 inch.
Accord to this chart (see link below) 7/16 is M10 (which are the bolts) so it might not be that big of a deal (whats 2mms?).
At some point higher compression heads will be used so I guess it isn't that big of a deal.
https://www.dot.ny.gov/main/business...bolt_table.pdf
Accord to this chart (see link below) 7/16 is M10 (which are the bolts) so it might not be that big of a deal (whats 2mms?).
At some point higher compression heads will be used so I guess it isn't that big of a deal.
https://www.dot.ny.gov/main/business...bolt_table.pdf
Safety Car
Joined: Dec 2010
Posts: 3,938
Likes: 498
From: Fords, NJ
Than I pretty much listen to information on this forum and ****ed myself, thanks. I went outside to check and see how big I drilled the hole out. If the 7/16 taps work I will be shocked. I might need to drill it out even bigger to more than likely 1/2 inch.
Accord to this chart (see link below) 7/16 is M10 (which are the bolts) so it might not be that big of a deal (whats 2mms?).
At some point higher compression heads will be used so I guess it isn't that big of a deal.
https://www.dot.ny.gov/main/business...bolt_table.pdf
Accord to this chart (see link below) 7/16 is M10 (which are the bolts) so it might not be that big of a deal (whats 2mms?).
At some point higher compression heads will be used so I guess it isn't that big of a deal.
https://www.dot.ny.gov/main/business...bolt_table.pdf
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Safety Car
Joined: Dec 2010
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From: Fords, NJ
Thread Starter
Instructor
Joined: Nov 2011
Posts: 181
Likes: 1
From: Franklin Square NY
Also there is pretty much no threads in the hole.
Drill and tap is the only way this is going to work.
Safety Car
Joined: Aug 2011
Posts: 4,447
Likes: 409
From: Portland OR
Is the hole too big for a heli coil?
How about a Time-Sert?
I would look into a possible correct fix before drill and tap to a US bolt.
I know myself, I have to get pissed, throw crisp around the garage, find someone to blame before I figure out I want to do things the right way. If possible.
Ron
How about a Time-Sert?
I would look into a possible correct fix before drill and tap to a US bolt.
I know myself, I have to get pissed, throw crisp around the garage, find someone to blame before I figure out I want to do things the right way. If possible.
Ron
Thread Starter
Instructor
Joined: Nov 2011
Posts: 181
Likes: 1
From: Franklin Square NY
Is the hole too big for a heli coil?
How about a Time-Sert?
I would look into a possible correct fix before drill and tap to a US bolt.
I know myself, I have to get pissed, throw crisp around the garage, find someone to blame before I figure out I want to do things the right way. If possible.
Ron
How about a Time-Sert?
I would look into a possible correct fix before drill and tap to a US bolt.
I know myself, I have to get pissed, throw crisp around the garage, find someone to blame before I figure out I want to do things the right way. If possible.
Ron
Now that we've covered that, I went outside with a 7/16 tap and it will go in until it reaches towards the top of the hole and stops (because I didn't drill the hole I assume).
Now, wit that said the hole is pretty much 7/16 which is very close to the m10 size.
Will a helicoil fit this hole, no idea. I've never used a helicoil.
Thread Starter
Instructor
Joined: Nov 2011
Posts: 181
Likes: 1
From: Franklin Square NY
To be perfectly 100% honest, a new 383 iron short block is constantly floating through my head. All I would need is a gasket set, head bolt set, the short block and an engine hoist.
Yank that son of a bitch right out in the middle of the street.
Yank that son of a bitch right out in the middle of the street.
Safety Car
Joined: Dec 2010
Posts: 3,938
Likes: 498
From: Fords, NJ
Here's an idea that MIGHT hold you over until you can remedy the situation...how about getting a longer fully threaded Grade 8 - M10 or 7/16 nut and bolt, and bolt it up. Looks like the top of the mounting boss is flat enough for a washer and nut to sit on !
Last edited by SG Lou; Aug 30, 2014 at 01:00 AM.
Thread Starter
Instructor
Joined: Nov 2011
Posts: 181
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From: Franklin Square NY
I looked into doing that with a 7/16 bolt but is a tad bit to big. I also looked at a video of a guy using 1 bolt to hold the starter in place. (which seemed to work fine for him).
So with that thought done with, do you think I can use and M10 or slightly smaller bolt to attach it. It seems to be an alignment thing more than a torque thing when it comes to the newer starter. If you look at the design it puts way more force in the other side of the starter.
Last edited by robert1989; Aug 30, 2014 at 01:14 AM.
Thread Starter
Instructor
Joined: Nov 2011
Posts: 181
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From: Franklin Square NY
I'm just worried I'm going to need two wait a week for M10 1.5 helicoils or something while a carrier pigeon brings them to me.
Safety Car
Joined: Dec 2010
Posts: 3,938
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From: Fords, NJ
I swear to god this bud light sucked my ideas out of my head and gave them to you.
I looked into doing that with a 7/16 bolt but is a tad bit to big. I also looked at a video of a guy using 1 bolt to hold the starter in place. (which seemed to work fine for him).
So with that thought done with, do you think I can use and M10 or slightly smaller bolt to attach it. It seems to be an alignment thing more than a torque thing when it comes to the newer starter. If you look at the design it puts way more force in the other side of the starter.
I looked into doing that with a 7/16 bolt but is a tad bit to big. I also looked at a video of a guy using 1 bolt to hold the starter in place. (which seemed to work fine for him).
So with that thought done with, do you think I can use and M10 or slightly smaller bolt to attach it. It seems to be an alignment thing more than a torque thing when it comes to the newer starter. If you look at the design it puts way more force in the other side of the starter.