- Joined
- Feb 8, 2014
- Messages
- 11,177
My son is building a new engine for his Subaru, he purchased this block from somewhere. The current operation is replacing the stock head studs with high strength 1/2 inch studs, so he can run 30 PSI turbo boost. This Subaru is a money sink, he breaks it just about every time he takes it to the track, but it's his money.:nuts: OK, I used to do that too, I guess it runs in the family.
11 of the 12 stud holes went just fine, BUT, in one of them he ran into an unexpected Heli-Coil. I heard it squealing just before I heard the drill bit snap. OK, now we have about 2 1/2 inches of shattered 27/64 drill bit, wound up in a Heli-Coil down a 4 inch deep hole.
The top couple inches of drill bit came out pretty easy with about 2 hours of probing around and twisting it around with some 1/8 welding rod stuffed down the flutes and a pair of vice grips.
Of course the rest of the drill bit is wedged into the aluminum in the bottom of the hole so it's not moving and there is no way to break it up because it's captured so tightly.
The problem: How to get the rest of this mess out and save the $1000 engine block that is currently not available from anywhere.
Here is what I did:
The engine block
Most of the broken pieces and another drill bit for reference
The tools
The first order of business was to drill a hole through the drill bit to get enough clearance to be able to break it up and get it un-wedged from the block. So up into he milling machine it goes. Start slow so the burr doesn't walk off to the side and bugger up the hole. Once the center is established, then you can pour the coal to it.
What is left of the 6 inch long carbide burr that I ordered for this project, the burr and the shank are fine, just not together anymore. I got it hot enough while drilling that the brazed joint failed, I guess I poured on a little too much coal. Fortunately, I had most of the drilling work done at that point so I was able to continue on with out it.
That was really an Oh S^%& moment
anic:, luckily, the burr was free in the hole and just fell out when I turned the block upside down. I'm going to attempt to put it back together, that will be for another day. If that doesn't work, I have a nice hard piece of 1/4 inch drill rod to use for something else.
Heli-Coil cutting tool, made from a 3/8 wood drilling spade bit, normally I would grind up a broken tap for this purpose, but in this case I had to reach down the hole about 3 1/2 inches. I would normally unscrew a Heli-Coil, but in this case it wasn't possible because there wasn't enough left to grab on to.
The round punch with a chisel end ground to act as a wedge to break up the drill bit, I keep a few junk HF punches around for using like this.
1/16 SS welding rod bent into a hook to grab stuck pieces of Heli-Coil that would not come out with the magnet.
After about another 3 hours of drilling, probing, careful punching, twisting, and looking down the hole with a HF inspection camera, I managed to get all of the pieces out. Now it's ready to accept the new Heli-Coil.:biggrin:
Too bad I can't charge him for my time.:whistle: That's OK, now he owes me one, again. Hmmm, my roof needs to be de-mossed......
11 of the 12 stud holes went just fine, BUT, in one of them he ran into an unexpected Heli-Coil. I heard it squealing just before I heard the drill bit snap. OK, now we have about 2 1/2 inches of shattered 27/64 drill bit, wound up in a Heli-Coil down a 4 inch deep hole.
The top couple inches of drill bit came out pretty easy with about 2 hours of probing around and twisting it around with some 1/8 welding rod stuffed down the flutes and a pair of vice grips.
Of course the rest of the drill bit is wedged into the aluminum in the bottom of the hole so it's not moving and there is no way to break it up because it's captured so tightly.
The problem: How to get the rest of this mess out and save the $1000 engine block that is currently not available from anywhere.
Here is what I did:
The engine block
Most of the broken pieces and another drill bit for reference
The tools
The first order of business was to drill a hole through the drill bit to get enough clearance to be able to break it up and get it un-wedged from the block. So up into he milling machine it goes. Start slow so the burr doesn't walk off to the side and bugger up the hole. Once the center is established, then you can pour the coal to it.
What is left of the 6 inch long carbide burr that I ordered for this project, the burr and the shank are fine, just not together anymore. I got it hot enough while drilling that the brazed joint failed, I guess I poured on a little too much coal. Fortunately, I had most of the drilling work done at that point so I was able to continue on with out it.
That was really an Oh S^%& moment
anic:, luckily, the burr was free in the hole and just fell out when I turned the block upside down. I'm going to attempt to put it back together, that will be for another day. If that doesn't work, I have a nice hard piece of 1/4 inch drill rod to use for something else.Heli-Coil cutting tool, made from a 3/8 wood drilling spade bit, normally I would grind up a broken tap for this purpose, but in this case I had to reach down the hole about 3 1/2 inches. I would normally unscrew a Heli-Coil, but in this case it wasn't possible because there wasn't enough left to grab on to.
The round punch with a chisel end ground to act as a wedge to break up the drill bit, I keep a few junk HF punches around for using like this.
1/16 SS welding rod bent into a hook to grab stuck pieces of Heli-Coil that would not come out with the magnet.
After about another 3 hours of drilling, probing, careful punching, twisting, and looking down the hole with a HF inspection camera, I managed to get all of the pieces out. Now it's ready to accept the new Heli-Coil.:biggrin:
Too bad I can't charge him for my time.:whistle: That's OK, now he owes me one, again. Hmmm, my roof needs to be de-mossed......
