Need advice on broken exhaust bolt restoration..pic attached

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Thanks in advanceThis is alum head 2004 5.3 chevy take out engine intended for a friends CJ-7 Jeep.....BOTH heads have rear most exhaust manifold bolts broken off...Here is pic of left side.Bolts are steel-heads are alum.I've seen all the vids about how to weld a flat washer and nut to broken bolts...But my question is, what is best way to prep end of rusted bolt for welding?   I'll be welding with engine on stand in flat position with Hobart 210mvp mig using c25 and .30 wireThanks!
Reply:Id machine shop those....Or if you feel crafty enough:1. Using a center punch, dimple the center of the bolt2. Using a center drill, drill the dimple made in step 1.3. Continue drilling the bolt until it's removed4. Clean up the threads with a quality tap4A. Drill and tap for a helicoil5. Install helicoilMiller Dynasty 200DXMiller Spectrum 250DMiller Millermatic 200Bunch of old blue dinosaurs....
Reply:Originally Posted by jontheturboguyId machine shop those....Or if you feel crafty enough:1. Using a center punch, dimple the center of the bolt2. Using a center drill, drill the dimple made in step 1.3. Continue drilling the bolt until it's removed4. Clean up the threads with a quality tap4A. Drill and tap for a helicoil5. Install helicoil
Reply:Weld a washer with a smaller hole than the size of the bolt to it then weld a nut to the washer. Let it cool and remove. Sometimes heat variations come into play. Trial will tell you what it wants. Looks like it dont need any prep. Go for it!I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Originally Posted by weldermikeWeld a washer with a smaller hole than the size of the bolt to it then weld a nut to the washer. Let it cool and remove. Sometimes heat variations come into play. Trial will tell you what it wants. Looks like it dont need any prep. Go for it!
Reply:Originally Posted by weldermikeWeld a washer with a smaller hole than the size of the bolt to it then weld a nut to the washer. Let it cool and remove. Sometimes heat variations come into play. Trial will tell you what it wants. Looks like it dont need any prep. Go for it!
Reply:Originally Posted by nikodellDone this a few times has always worked for me.
Reply:Originally Posted by pigeonpoop...I'll post pics, win or fail
Reply:At $369 it had better be more than magic.  No thanks... Originally Posted by nikodellNext time use one of these first,  a wrecking yard guy told me about this and claims the thing is magic.
Reply:Originally Posted by nikodellDone this a few times has always worked for me.
Reply:Originally Posted by nikodellNext time use one of these first,  a wrecking yard guy told me about this and claims the thing is magic.
Reply:Originally Posted by dellwasAt $369 it had better be more than magic.  No thanks...
Reply:Originally Posted by BD1I did it, then bought NEW CAR !      Most that can happen is you will lose a friend .
Reply:BTW.....For all you guys here with any Chebby mid to late 2000's truck with Gen III Vortech V-8 engine......You might wanna check your exhaust manifold head bolts to see if any are broken.....It's a very common thing.....Worst case is truck will exhibit a misfire and throw confusing codes but you may never actually hear exhaust leak.....rearmost ones always break first, then perhaps several before you notice
Reply:To answer you question on prep, with that bolt, things look pretty clean and I don't see a point to prepping it prior to welding. If it was heavily rusted then possibly a drill bit or carbide bur could have been used just to remove the rust enough so you could get a good contact to get the arc started. Many times it's not needed though.As far as induction heating, I'd never seen that little devise before. I have seen some induction heaters used for forge work in the past and always thought they were kind of neat, if some what limited in what you could heat with one. For someone doing blade work or repetitive items that were always the same stock size, I could see them being very useful, if a bit pricy..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by pigeonpoopNot to worry....I have a low mile 2004 5.3 take out engine and a friend with an old cj-7...We decided we will drop it in his Jeep.....two broken exhaust manny bolts ain't gonna cost me a friend...promise...his wife might throw rocks at me, but me n him will stay buds
Reply:Thanks, you beat me to it.  Figured someone musta built a homemade one... Originally Posted by nikodellYou could build one for very little if you are electrically inclined. They live with this thing in hand as they pull parts and would not do without it from what he says.  A quick Google found this.http://www.rmcybernetics.com/project...ion-heater.htm
Reply:Originally Posted by BD1I  would say that there are MANY WIFES that would throw rocks at all of us ! That's better then knives or shooting at us .
Reply:Tig it then pour some oil on it, Tuffcreek on here showed me and now I do it, works like a charm.Tim Beeker.
Reply:After welding the washer and nut, I use my impact with an adjustable air flow valve from a paint gun hooked on.I start at zero pressure, pull the trigger with one hand while the other gradually dials up pressure till it softly tap-tap-taps the bolt out.On old heavily rusted parts it still will snap off and take up to three tries. I've never had it go to four.Good luck man Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Well did you get it out yet? Im doing field repairs today and just did 5 in about three minutes. I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Originally Posted by weldermikeWell did you get it out yet? Im doing field repairs today and just did 5 in about three minutes.
Reply:I had several broken exhaust studs on my 6.8L Ford F250. I took the manifold off by any means that would work. I cut a couple of studs, broke a couple as well. Some were corroded below the gasket surface, some above. I took my little 110 mig, with innershield wire, stuck the nozzle in the hole, and put a few tacks on the stud. No kind of prep either. I built up the stud to minimum flush with the head. I tacked a nut to what I built up, put a wrench on the nut and unscrewed the studs. I put all new studs in with antiseize, new gaskets, replaced the manifolds, and all is well. One side was repaired 5 years ago, the other 2 years ago. No leaks yet.
Reply:Yup Weld method here too. I had the same issue with my wife's 6.0 Caddy Escalade with a 6.0 (same family as the 5.3). I also did this method on my F250 superduty with a 5.4 gas motor.www.tjsperformance.comDynasty 300 DXHTP 240HTP Microcut 380Hyperthem 85JD2 Hyd Bender and HF Hyd Ring Roller all in one =(Frankenbender)Bpt. Mill/DRO4' x 8' CNC Plasma TableInstagram: tjsperformanceYT: TJS Welding and Fabrication
Reply:Originally Posted by MinnesotaDaveAfter welding the washer and nut, I use my impact with an adjustable air flow valve from a paint gun hooked on.I start at zero pressure, pull the trigger with one hand while the other gradually dials up pressure till it softly tap-tap-taps the bolt out.On old heavily rusted parts it still will snap off and take up to three tries. I've never had it go to four.Good luck manWelding forum or not, I'm siding with jontheturboguy on this one.Through drill the bolt and then a spline extractor would have it out so fast and easy, with no risk to the head - why chance it otherwise?
Reply:Originally Posted by denrepWelding forum or not, I'm siding with jontheturboguy on this one.Through drill the bolt and then a spline extractor would have it out so fast and easy, with no risk to the head - why chance it otherwise?
Reply:Common problem on all GM LS engines, same bolt postion.  Weld washer, then nut on. It will come right out.If you drill the bit can glance of and destroy the aluminum head.Idealarc 250AC 225SVictor OA-older made in USA stuff.And a crap ton of other stuff.
Reply:Originally Posted by M J DI like the cordless impact driver for stuff like that ,it really impacts without all the twisting force. Works good on the smaller fasteners that always seem to break so easy in the land of rust.
Reply:Needs to be done by hand almost always. You gotta feel what's going on. A lot of times the studs are bent and want not, and that plays a big part in doing it once, verse three or more times. And then when a flush break breaks again on the third try and is now 1/4 deep. Your fcked. I have my own methods for that but it's a long story. Impacts will work fine tho on certain extractions with a fine touch and feel. Anyway, fck it's Christmas who gives a shlt! Enjoy guys!I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Ever use the candle trick?  Heat it up nice and hot then stick a candle on it, wax will follow the threads and it usually backs right out.  Course this will only work if enough of the head is left to grab with vice grips, etc. Originally Posted by weldermikeHuh! I have probably done over a thousand with the heads still on the vehicle. Never ruined one head and I don't think I ever not gotten one out. May have taken multiple tries and heat theories, but now just thinking. I don't think I ever had one beat me yet. I have many recipes for this tho, not just the weld a nut and washer deal. I'm a better talker than a typer LOL. I can explain things in person better.
Reply:Originally Posted by dellwasEver use the candle trick?  Heat it up nice and hot then stick a candle on it, wax will follow the threads and it usually backs right out.  Course this will only work if enough of the head is left to grab with vice grips, etc.
Reply:I do these all the time. Usually I hit a nut with the same i.d. as the broke off bolt with a step bit to prep it for the weld. Then I clamp my ground as close to the bolt as possible and run my welder as hot as I can. I try to angle the gun as straight into the bolt as I can to penetrate the bolt. Then work it back and forth until it backs out.
Reply:Originally Posted by kald If you drill the bit can glance of and destroy the aluminum head.
Reply:Originally Posted by denrepOkay... well wait'll we see what that same guy can do with a welder. --------------If a bolt's not stuck, then about anything will turn it out. Probably can even be "walked out" with an ice pick, or a tack weld may do it, or  it may back out during drilling.However,  if a bolt is stuck enough to have twisted off during turning, it's going to be tough to build up a weld "glob" that approaches the strength of the original bolt - which itself wasn't strong enough to transmit the torque needed to turn the bolt anyway.For a really stuck bolt, when heating is limited, I vote for drilling. Drilling a through hole does some important things. First, the drilled center relieves concentric pressure and also opens a path for heat and penetrant. Then, the drilled hole gives the extractor a surface to get an evenly distributed  "bite" over 100% of the broken bolt's length. There's no way a weld deposit, even at 100% of original bolt strength, can evenly transmit as much force so completely throughout a stuck bolt, as a splined extractor can.
Reply:WELDERMIKE   ''Never ruined one head  '' .  Nothing better then good head !
Reply:I take a larger but, say 1/2-5/8". Center it over the stud then I center a mig gun in the hole and start welding, concentrating on the center then filling the nut. Sometimes it breaks and you have to do it a couple times. It will easily come out without damaging the parent material even aluminum. Some people weld a washer on, I don't.
Reply:7/8" long hardened set screw seized in aluminum F/M mag housing.  Heat and impact driver (hammer type) wouldn't touch it.  Couldn't drill it and killed my die grinder cutter and stones.  5th or 6th "build it up and weld a nut on" method with a little PB Blaster did the trick without hardly leaving a mark on the aluminum housing.http://weldingweb.com/vbb/showthread.php...ion&highlight=blackbart's larger than bolt/stud nut is a key factor.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:I do these all the time. Usually I believe these break because they aren't sized properly. Its always the rear bolts and on occasion the fronts. I think this is because the flange casting is too thin for this small of a bolt to keep it from warping which pops the bolt heads off at the threads.
Reply:Kroil then left hand drill bit, extractor , next washer weld n nut . May back out on the drill?
Reply:denrep,After rereading my comment about this being a welding forum I can see how it might sound disrespectful..... That wasn't my intent.....My aversion to the suggested method of drilling is due to my proven lack of dexterity and skills.....I'd fersure mangle it if I attempted to drill it out.To the other posters, I agree is seems to be a design defect where the bolt heads just fall off due to fatigue and the bolts being way to small.Thanks all you guys for your suggestions....I'll get out there next few days and give it a shot.  right now I'm working a lot of 16 hr shifts and it's too frigging cold out there for this old man
Reply:Originally Posted by nikodellOne a few doors down has knifed her husband at least twice from what I have heard, I stay well clear of the whole family.
Reply:It's not just GM that does this... I fix 5.4 Fords, and 4.7 Dodges with the same issue all the time. The thermal expansion of the manifolds makes them either lengthen, or curl up like a banana. Many heat cycles eventually work hardens and pops the end bolts. We see it most often on trucks that are worked pretty hard. The majority of the time, the remaining bolt isn't stuck that hard, and an extractor will take them right out. Depending on how accessible it is, I also use the welding method. A lot of the trucks with the rear cylinders stuffed back in the tunnel suck to get to, and getting a drill back there and straight just isn't worth it. With an engine on the stand, I'd probably just drill it and use an extractor. I wouldn't expect it to be stuck too tight. As somebody else already mentioned, a left hand drill bit may even walk it out. The only difficulty with that idea is if the bolt is so work hardened that cutting it is more trouble than it's worth. Then I might break out the welder just to save time.
Reply:Originally Posted by blackbartI take a larger but, say 1/2-5/8". Center it over the stud then I center a mig gun in the hole and start welding, concentrating on the center then filling the nut. Sometimes it breaks and you have to do it a couple times. It will easily come out without damaging the parent material even aluminum. Some people weld a washer on, I don't.
Reply:Originally Posted by blackbartI tried to edit, I meant take a big nut, not but, however big butts cannot lie......it's a song.  I have done this on aluminum a lot without damage.  The mig wire bonds to the stud and starts building up from the center, leaving the threads alone, even on a bolt that is broken well below the surface.
Reply:Originally Posted by blackbartI tried to edit, I meant take a big nut, not but, however big butts cannot lie......it's a song.  I have done this on aluminum a lot without damage.  The mig wire bonds to the stud and starts building up from the center, leaving the threads alone, even on a bolt that is broken well below the surface.
Reply:I'll be right back.....
Reply:Did you get the fcking thing out yet! Jeesh man.I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Originally Posted by WenValleyI'll be right back.....
Reply:I wanna see how Jody would handle that root pass...There ain't a code gap there and it don't hold still, and I doubt she will