Cracked 5.7 block at Starter Bolts

[mattyg]

New to me 1996 k2500 with the 5.7 and 4l80, 95k miles, runs mint, starts like crap. So I went to investigate why the starter grinds and sometimes binds up and I find the infamous cracked block, no front support on the starter. So what is the preferred repair?? It looks like a JB weld repair was attempted in the past. Starter bolt bottoms out and toques to spec. Flywheel looks like crap, i found lots of metal filings. I was thinking pull the motor and braze in a stud, or braze the broken piece back on, align a new starter and flywheel and send it?? I just bought this truck, i got a good enough deal on it, first GMC product ever, i have an engine hoist and all the tools, just sucks being baptized by fire into the GMC club. Anyways, advice would be much thanked. Pics

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[stutaeng]

Yikes! I didn't know this was a common problem!

Can you do brazing or TIG welding? I'd hate to pull that engine for that, but I don't really see another solution. There's no material to do a Heli-coil or anything like that. Can it be brazed in-place?

Do they making something like this for this engine?

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[stutaeng]

How about welding a stud in there? It would be easier. Break off the fracture piece and weld the stud to the threaded/fractured surface. Then just slide the starter and put a nut on the bottom end of the starter.

 

[HotWheelsBurban]

You might want to check out the distributor cap and rotor. They may be trying to fire multiple cylinders at the same time. That will cause the starter and drive to get busted and can tear up flywheel teeth. Had to do this on my 99 5.7 Vortec Burb,a few years ago. Thankfully it didn't crack the block like yours, but probably would have, left unfixed. Also be sure the starter bolts are the correct ones. The smaller starter uses different bolts, and if someone used the wrong bolt and overtightened it, coulda caused this cracking too. On mine, it broke the end frame ( housing) of the starter into multiple pieces, and chewed up the flywheel teeth. Had to trade a buddy of mine (who had access to a lift) a car to R&R the flywheel and starter, master cylinder and the wheel cylinders, and put tires on it. The cap was cross firing; apparently Vortec engines are bad about this. Another reason to run the blue rotor and cap with brass contacts and the vent. And have the spark plugs wires in the factory looms, because that helps keep them from touching each other.

 

[HotWheelsBurban]

How about welding a stud in there? It would be easier. Break off the fracture piece and weld the stud to the threaded/fractured surface. Then just slide the starter and put a nut on the bottom end of the starter.

That's what someone did on a 79 Burb 350 that we used to have. The engine was a target master and they were notorious for bad castings. It cracked off the side of the block.

 

[mattyg]

How about welding a stud in there? It would be easier. Break off the fracture piece and weld the stud to the threaded/fractured surface. Then just slide the starter and put a nut on the bottom end of the starter.

Yeah, the repair will probably be something like this. Still need to replace the flexplate. The motor looks simple enough to remove at least...

 

[mattyg]

You might want to check out the distributor cap and rotor. They may be trying to fire multiple cylinders at the same time. That will cause the starter and drive to get busted and can tear up flywheel teeth. Had to do this on my 99 5.7 Vortec Burb,a few years ago. Thankfully it didn't crack the block like yours, but probably would have, left unfixed. Also be sure the starter bolts are the correct ones. The smaller starter uses different bolts, and if someone used the wrong bolt and overtightened it, coulda caused this cracking too. On mine, it broke the end frame ( housing) of the starter into multiple pieces, and chewed up the flywheel teeth. Had to trade a buddy of mine (who had access to a lift) a car to R&R the flywheel and starter, master cylinder and the wheel cylinders, and put tires on it. The cap was cross firing; apparently Vortec engines are bad about this. Another reason to run the blue rotor and cap with brass contacts and the vent. And have the spark plugs wires in the factory looms, because that helps keep them from touching each other.

The AC delco tune up kit just arrived, lol

 

[HotWheelsBurban]

Yeah, the repair will probably be something like this. Still need to replace the flexplate. The motor looks simple enough to remove at least...

I think my guy dropped the trans or moved it back. He has bad back problems from a truck wreck many years ago, so he's figured out how to work on vehicles in ways that don't hurt so much.

 

[mattyg]

I think my guy dropped the trans or moved it back. He has bad back problems from a truck wreck many years ago, so he's figured out how to work on vehicles in ways that don't hurt so much.

I have a bad back too, i have child labor though..LOL

 

[mattyg]

Getting a head start on pulling the engine, the cordless impacts and ratchet makes these jobs really enjoyable.

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