There are guys on here a hell of a lot smarter than me about this stuff but unless I'm mistaken that bolt threads into the snout of the crank which means either it broke or it tore the threads out. I sure hope not and maybe I am way off base but not sure how else what you are describing could happen.

 

That’s bad news for certain.
I have a “ modified “ cats claw from my previous life as a wood butcher , that will allow you to get under the edge of the bolt head.
Hopefully you can visualize how using something like that, combined with turning while prying might allow you to extract it.
Then you would have to decide how to “ re-thread” the snout.
I’m an advocate of Helicoil inserts, but it would need to be a 3D ( three times the diameter of the bolt ) for me to be confident of its integrity.
Then the challenge of drilling ( hopefully the bolt didn’t break, because it’s a grade 8) and taping and installing the STI ( steel threaded insert) with a locking agent.
Or…..your looking for a crank 🤷

 

This is what I call a cats claw

 

I had this happen on a 1980 z28. Loved the car. It ran well. Motor was not new..
I had the threads pull out. For a while I ran it with no bolt. Like early motors with just a press on balancer. Eventually I had it arc welded to the crank. Not a way to fix it but I solved the problem til I either rebuilt the motor or sold the car. Not a great way to fix. But beats replacing or rebuilding a lesser motor. It would work if an emergency fix.

 

Sounds like you stripped the threads in the crankshaft. I would remove the bolt by pulling and turning, try running a standard tap then a bottoming tap as far as you can into the hole then buy a longer grade 8 bolt to maximize the thread engagement. Also don't turn you engine over using a balancer bolt. I have a tool that attaches to the 3 pulley bolts and has a 1/2" square drive on it.

 

I have a tool that attaches to the 3 pulley bolts and has a 1/2" square drive on it.

Any idea what that tool is called and where to buy it?

 

It may be that the bolt bottomed out on the inside of crank(bolt to long). That would be maybe a lessor repair if you can use an easy out once you get top part out. I would use pliers or the claw suggested to see if you can get the top part of bolt out. Then see what you have to work with

 

You’re not going to like my answer, but you now have to fix it.

 

If your talking about the pictured tool referenced as nail claw any hardware store should have it. The picture shows home depot.

 

Put a good vice grip on the blt and get a pry bar behind it and use the bar as a lever it will come out , the threads are stripped . next clean out all debris with compressed air and brake cleaner . Now its time to fixit . Get a new bolt and washer make sure its grade 8, next get a 7 / 16ths fine thread HELI COIL Kit. use the drill to get it to proper size . Next clean it out start the tap straight some cutting oil and start tapping slow steady and straight . Go ib a few threads back out a bit go in a few more back out . Follow this till you cant you will know when to stop as it wont cut any more . Dont force it . Back it out all the way and clean it out with air and Brake clean CRC green can. re insert the tap and run it again with oil. Back it out re clean . Now get a HeliCoil put it on the inserting tool and slowly wind it in till your two threads below the face of the crank snout . Next get a flat round punch and break off the inserting tang blow it out your done . This does require a ceain amount of technique experience and expertise but if you go slow and steady you will get it done and gain experience. In 50 plus years i have done hundreds of stripped threads with all kinds of repair methods like Time zert and others . Good luck . Alex

 

When you get the bolt out, decide if the bolt stripped or the crank stripped. If the bolt stripped then use a thread chaser to clean out the threads in the crank and put in a new correct length bolt. If the crank is stripped then you need to rethread as described above. As mentioned, the best thing to try first is to put pull tension on the bolt while unscrewing it.

 

Its probably stripped and this is exactly why I tell people to never use the bolt to turn the engine over. There are tools for that reason.

Amazon.com: ProForm Crankshaft Turning Tool, Balancer Mounted, 1/2 in Drive, Stainless, Natural, Chevy/Ford, Each : Automotive

Shop Amazon for ProForm Crankshaft Turning Tool, Balancer Mounted, 1/2 in Drive, Stainless, Natural, Chevy/Ford, Each and find millions of items, delivered faster than ever.

www.amazon.com

You should be able to get it out with a pair of vise grips like ss327 said. Then you can either helicoil it or tap it out to big block size. It can be tight doing it in the car but it can be done.

 

Don't know if this will work but as mentioned, pulling and turning. Weld a smaller size bolt to the existing bolt head, slip a pivoting ratcheting wrench onto the balancer bolt and have someone else pull on the welded bolt hoping that maybe some damaged threads will engage.

 

Would the above referenced crankshaft turning tool work without taking off the crank pulley first ? I am asking because I have been doing this exact same thing, turning the engine over using the balancer bolt.I convinced myself many years ago that turning the engine over every couple of weeks while the car was in storage was a good idea. is there a better way to do this?

 

If I have the spark plugs out, I typically pulling on a belt by hand while using a socket on the alternator nut.

 

Thanks .I can certainly try that. And yes all the plugs are out

 

SS27's idea with the vice grips is least destructive. But if they slip off, the other three options are:
1. weld a threaded rod to the head of the bolt, then slide a large socket over the threaded rod and a nut and washer to pull the bolt out.
2. use a wood chisel or similar tapered tool to drive under the head of the bolt or edge of the large washer while turning the bolt to remove it. You have to shim under the chisel as you get the bolt to begin coming out and work from side to side or drive another chisel in the other side opposite the first. Probably scratch your pulleys or gouge it.
3. Fabricate a 1/2" +/- thick bar to span across the harmonic dampener with bolt on each end and clear the timing chain cover. These bolts will bear against the block. The bar must be wide enough to drill holes to match the bolts holding the pulley to the dampener and a large hole at the center line of the crank to put a socket thru to the bolt. Then tighten the outer bolts to pull the dampener while turning the stripped bolt to remove it.

 

Don"t want to hijack this thread. Vega short answer, battery for the car is in the basement of my house for the winter just a royal PITA to drag it to and fro every couple of weeks. I have had the car for 27 years and feel over time it makes a differance

 

Okay, I got the bolt out. It took a prybar to do the pull and turn action, even more difficult by myself. I have March serpentine pulleys on this engine. It looks like there were not a lot of threads engaged. I measured the bolt and it is about 2-1/8“ long. Go with a longer ARP bolt? Looks like most of them are 2.5“ long. Do you think that’s long enough?

The funny thing about this is I’ve turned the engine with the same bolt before. I was researching what timing to use with my EFI and read probably over a dozen posts and watched three videos (all from businesses) and none mentioned not using the bolt to turn the engine or I would not have done it. The three videos all showed turning using that bolt. Lesson learned. I now have the three hole tool. Thanks everyone for the help.

 

We love a happy ending.

 

Run a tap into the hole in the crank and blow it out with compressed air before installing the new ARP bolt.
Measure the depth of the threaded hole to determine how long of a bolt you can use. Be careful not to use a bolt too long that would bottom out.

the good is it looks like the bolt threads stripped and not the threads in the crank so you should be good to go with the 2 1/2” bolt

 

Not a tap, thread chaser first. different animals. And that does not look like the correct bolt. Do the ARP.

 

Bryon,
I forgot about this thread I found a stock GM bolt and it measures 2.300 under the head so the ARP one should be fine. The one you have now almost looks like the Pioneer ones.

 

Measure the depth of the hole then indicate depth on tape. This will help you from bottoming the tap. Be sure to use a penetrating oil to help with the taping process. Be careful as you don’t want to break the tap