ktm Posted March 19, 2007 Share Posted March 19, 2007 I have never had to remove a sheared bolt/stud out of a head before, and I am leary to learn on my P90a. The engine is on a stand and both manifolds have been removed. The stud by cylinder 1 snapped flush with the head. I have read about drilling out the stud, but I am a bit concerned about my abilities to do it properly. I know that I can always 'correct' any overdrilling by either going to the next size up or installing a helicoil. Is there anyone in the Orange County area that may be able to help me out? I have a drill, Dremel and Craftsman tap/die set. Quote Link to comment Share on other sites More sharing options...
naviathan Posted March 19, 2007 Share Posted March 19, 2007 Get a set of reverse cut drill bits and try those. usually with the exhaust studs they will come right out. I used an extractor set and I really did not need to. They were just that easy to remove. Quote Link to comment Share on other sites More sharing options...
ktm Posted March 19, 2007 Author Share Posted March 19, 2007 I do not plan on using any EZouts or extractors. I have read far too many horror stories about them. If need be I will either drill it out using successively larger bits or use the reverse drill bits you mentioned. I am just concerned about being too far off center and doing serious damage. Quote Link to comment Share on other sites More sharing options...
naviathan Posted March 19, 2007 Share Posted March 19, 2007 Just use a small bit and a punch to tap a center in the end of the stud. Most of the broken studs I've run across were due to warping in the manifold so the studs weren't froze in place, they just snapped off at the end. I can understand your apprehension for the easy outs. I have a broken exhaust flange stud with the tip of an easy out stuck in it. Can't do anything about it so I guess it's time to throw a header on. Quote Link to comment Share on other sites More sharing options...
speedracer888 Posted March 19, 2007 Share Posted March 19, 2007 i just had the same problem with my 83 380zxt and i was missing my #1 and #6 stud, all i did was drill them out and retapped them... Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted March 19, 2007 Administrators Share Posted March 19, 2007 I’ll outline two procedures for removing broken bolt/studs… The Drilling out procedure… 1) Center punch as dead nuts to the center of the steel bolt/stud as possible. 2) The reversing drill bits are great. Some times, just the reverse rotation of the bit alone will grab and extract the broken bolt/stud. Choose a small bit to pre-drill all the way through the broken bolt/stud, (this can be a standard drill bit). Be VERY careful not to let the bit wander or to drill at an angle. An extra pair of eyes at 90 degree angle to your own viewing angle is best. Also, be careful that you don’t drill through the aluminum head on the back side of the bolt. You’ll be able to “feel” when the drill bit passes through the broken bolt/stud. 3) Now using a reverser rotation bit, (a standard bit will also work if you don’t have the reverse bit,) that is a little smaller than the OD of the bolt/stud itself, (the bolt/stud should be a 8 x 1.25 mm thread size), drill “carefully” till either the broken bolt/stud backs out on its own or you end up drilling all the way through the broken bolt/stud again. 4) If your drill bit is at all close enough be touching the actual threads of the hole and it didn’t come out. Stop right there and take the head down to a machine shop and have them finish the repair. You might be able to save it on your own, but 9 chances out of ten, it’ll end up being an ugly mess that wasn’t worth the time and effort and it most likely wont be as good as a Machine shop could do, i.e. straight, aligned, and located in the right spot. I’ve repaired many of those “well if I just kept drilling…” mistakes… (see pic below…) The Easy-Out method… First off, just by saying the word Easy-out usually brings up firm bickering from both camps of they "DO" or "DON'T" work. I’ll give you my take. I have used Easy-Outs of many different styles and configurations and still use them from time to time, (situation dependant), and they do work, but not all the time. When the Easy-Out wont get the broken bolt/stud out, then it's time to just clamp the part down to the mill table and start to perform surgery. Here are few techniques I employ when using Easy outs… 1) If there is any portion of the broken bolt/stud protruding above the surface, smack it and smack it hard with a hammer. Now heat it up with a torch till it starts to glow, let it cool just for minute or so, the smack it again! Smack it HARD!!! The smacking will help to break free the corrosion. The heat will helpfully help break free any thread locker and the expansion difference between the head and bolt sometimes is enough to break the corrosion free as well. (this trick works wonders for removing those stubborn SBC oil galley plugs…) 2) If you can get a pair vice grips around the protruding portion, then by now, 75% of the time, it will turn right out, that is if you can get a good enough grip on it. 3) If you can’t get a grip on it, then center punchy the broken bolt/stud as dead nuts center as possible. Now predrill the bolt/stud all the way through as in the "drilling out procedure" above. Now use the recommend drill size for the Easy-Out you are using, (some Easy-outs are all-in-one affairs with the drill bit and extractor as one piece). 4) If you end up breaking the drill bit or easy-out in the hole, just swallow your pride and take the head to a machine shop and have them fix it before it turns into a butchered mess. If you try and save a broken Easy-Out on your own, you will end up with a butchered bolt/stud repair that would even make “bubba” cringe… Here is one such repair of a butchered exhaust manifold bolt/stud, (same location you are fighting on a P-90 casting). We just drilled it out a little bigger than the butcher hack job, tapped it and installed a large solid pipe plug, located the placement of the original bolt hole, drilled and tapped it on the mill, then resurfaced the intake/exhaust surface. Now it is good as new… (some of you guys might recognize this particular P-90 head…) Quote Link to comment Share on other sites More sharing options...
S30TRBO Posted March 20, 2007 Share Posted March 20, 2007 Nice write up Paul, we should sticky this reply... Quote Link to comment Share on other sites More sharing options...
greenmonster80 Posted March 20, 2007 Share Posted March 20, 2007 A technique we use in the Artillery community for a rusty or stuck component is to heat it up with a torch as BRAAP instructed, except we blast it with a fire extinguisher to really shock the crap out of it. Never had anything still stick after a couple blasts. Just make sure you do not use a halon fire extinguisher. But really, don't be skiddish, it is just a datsun. Hit it with a hammer, punch and easy out. Will work out fine as long as you are paying attention.. Quote Link to comment Share on other sites More sharing options...
steveosupremeo Posted March 21, 2007 Share Posted March 21, 2007 hey guys, i have something to say about this, when i started working on my maxima N47 i had a roken stud in the last exhaust hole and instead of just drilling it out like i have before i decided to try the reverse spiral style ez out, didn't work very well for me, just scraped the bolt where i had drilled the pilot hole. then i grabbed one of the square peg style ez outs. felt like it started turning, and it did, turned the ez out right in half. i went into a cussing fit for a long time. called a bunch of machine shops and no one would even look at it. so i went to sears and bought a bunch of the smallest diameter cobalt coated drill bits and me and another tech drilled out around the little extractor until we were able to use a center punch to beat it out with a 2.5lb hammer and grabbed it with the needle nose pliers. we then tapped it to 10x1.25 because of course, like Paul has said, you will mess up some of the aluminum. there was still a very small portion that the tap didn't take care of but its very little and i checked to make sure i could tighten the bolt down good and it was ok. very very frustrating experience. started looking at my p90a and noticed the first and last studs broken off in it. might just tap them all out to 10x1.25, lol Quote Link to comment Share on other sites More sharing options...
ktm Posted March 21, 2007 Author Share Posted March 21, 2007 I managed to drill 95% of the stud out. I have remnant threads left in the hole though. I was able to drill straight and true and only kissed the back of the hole once with the drill (was not expecting the breakthrough). Quote Link to comment Share on other sites More sharing options...
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