I was just snugging up my bellhousing to my block (SBC) when one of the grade 8 bolts snapped off inside the block. I don't think I excessively tightened it it just snapped. I have had bad experiences with EZ outs in the past so I did a search here on extracting broken bolts. I tried the weld (MIG) a nut to the bolt trick. The nut sheared off and Im afraid that I welded the bolt to the block as it tried sanding it down and can't differentiate between the bolt and the block any longer. I thought that the iron block wouldn't allow the weld to stick? Am I fucked? all advice is appreciated. Thanks
Thats a bitch.. But can you get a centre punch on the outer edge of the bolt to try and turn it?? Or maybe cut a decent slot cut across the end showing, and use an impact screw driver?? Otherwise, as elscotto said, drill it the in centre (right thru) start with an 1/8" drill ( small drill is easier to work in the centre of the bolt) then work up drill sizes..
It sounds like the bolt bottomed out in the hole then snapped. Usually if it is bottomed out, it won't come out the easy way... Your best option is to drill it. Start with an 1/8 bit right in the center turning nice and slow with lots of lube. Next, go to 13/64 or so, then finally, 5/16. After drilling, damn near all the bolt will be gone and you can either pick out what is left, or run a 3/8 bottoming tap in the hole and all will be well. For your situation, I would stay away from an easy out and be carefull with the tap also. Taps and easy outs are about 40 on the Rockwell C scale (hard as woodpecker lips) and if you break one, you will NEVER be able to drill it out. Be carefull, go slow and you will be fine. Good luck, -Abone.
Put the bellhousing on it and use the hole in the bellhousing as a guide for a left hand twist drill to drill it out.
If you have access to a lathe, make up a series of bushings to fit the hole and that will keep the drilling on center. Or keep opening the bushing as you change drills. Go with 1/8, 3/16, 1/4. From there be careful since the tap drill for a 3/8-16 is a 5/16. Bob
I'm going to try and find a left twist drill. theoretically, the weld should not stick to the block though, am i correct?
Try hitting it with a chisel. I buy my LH drills at MSC Direct, you may need an account though. They are also known as screw machine drills. Bob
No, it will stick, but will be very brittle at the joint. Next time, don't use grade 8, and make sure it is not too long. Also, you should have welded a 3/8 flatwasher to the bolt shank first, starting with a high heat at the center, and then pile it right on, and then cover the washer, too, before you stop. Then weld the nut to the washer. That would have shrunk at least the top part of the bolt. Let cool completely. Then rock it back and forth to get it to move a bit. Takes practice to not snap it. I am not sure if I would drill. (depending on what it looks like now) I might trying smacking the end with a 5/16 flatnose punch to maybe break that brittle weld line. Then do the washer and nut.
Ditto, 56 Don's post. LOVE those left hand drill bits !!!!!!! And, use the bell housing as a drill and center punch guide 4TTUK
You can try the slob approach and install the bell housing using the other bolts and just drive it. Sometimes you can do more damage attempting to correct a problem. Who will know except a few thousand of us.
The reason I did not try the washer was because the bolt was recessed inside the hole. I am a little reluctant to try welding again as I'm concerned the weld will stick to the threads. Thanks for he advice Posted from the TJJ App for iPhone & iPad
If it is recessed a lot, that complicates the drilling. By welding to the top, it most likely burned into the block threads a lot, and the weld material will be stuck real good to the bolt. As you try to unscrew the bolt after drilling, those globs will be locked into burned pockets in the threads...just like a key holds inside a keyway. You may have to drill oversize, like 3/8 size bit, to take out all of the melted threads and a bit of the bolt shank. Not an easy fix at this point, unless you were good at centering the hole, and drilling it all out for a helicoil.
I'd probably leave it if it was one of the top ones. and I agree with F&J... don't use grade 8 bolts. No reason to.
probably wont bother anything. id had surgery so i paid a local chevy garage mech to put a clutch in my s10 , i was under it a year or so later and they left a bolt out of the bellhouing. sold it six years and over a hundred thousand miles later . no problem
i know most guys prefer to do things like this by themselves, but if you've welded it to the block try calling a machine shop to get a price quote, I would think it should be cheaper then a new block, and you'll end up with all of the bolts holding your motor and trans together.
Out of curiosity, why the recommendations not to use grade 8 bolts? Because they are hard to drill out in cases like this?
And they are brittle Get The Book http://www.carrollsmith.com/books/ Posted from the TJJ App for iPhone & iPad
Buy a $10 set of transfer punches from a Co. like MSC. USe the bellhousing as a guide to mark where the hole is. Then drill it. Or use a Dremel to remove your weld, then procede with trying to get the bolt out.
They aren't needed or necessary, GM built millions of cars and trucks with grade 5 bolts holding the bellhousings on. Overkill just for the sake of overkill doesn't really accomplish anything. That they are harder to drill out really isn't the issue.
Left handed bits, no easy-outs. Some shops can use Electronic Discharge Machining to get them out. I'd probably try driving it one bolt short, though.
A small tip cutting torch will blow the bolt out and not hurt the block. Might need a helicoil to get a bolt threaded in it after, though.
So they shouldn't be used here because they are too brittle for the application, as noted above? Trying to understand, before I button mine up.
The coolest thing I ever saw on stud removal was in a muffler shop. Several years ago I dragged home a 1932 Chevy coupe and the engine ran good but the exhaust was junk. I would almost bet the stud in the exhaust manifold was original and the nut was frozen to the stud. I took the coupe to the muffler shop and the mechanic did not even attempt to take the stud out, instead took a torch and heated the mainfold around the stud cherry red. He then threw a styro-foam cup full of cold water on the stud and manifold, put a socket on the nut and the stud backed right out! He repeated this on the second stud the same way and got the same result. I have no idea how it works but I saw it..
Heli coil did the trick. I was lucky to be able to drill on center. I'm pissed that I made such a stupid mistake and wasted my day trying to fix it. Lesson learned lol! Posted from the TJJ App for iPhone & iPad
Excellent reference guide for fasteners. http://www.fastenal.com/content/documents/FastenalTechnicalReferenceGuide.pdf Bob
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