Broken head bolt removal. K301 12HP

[Fordiesel69 267]

Over near the exhaust there is a broken head bolt.  It is broken about 1/16" above the deck.  I can definatly weld a nut onto it and try to back it out, however I am just wondering if I can apply some heat to the fin area whitout warping anything? 

[SousaKerry 502]

Probably better off to drill it out and re-tap it.  If you have access to a good sturdy drill press or mill it makes it a whole lot easier.

[305 380]

i would try to get it out first. when drilling and re-taping you sometimes get it off a bit and not into the original threads. if i was doing it i'd use my tig welder to weld the nut on. you get better penetration. start the arc and just dab the filler rod in the pool to build it up , then add the nut and finish the weld. the heat from the tig is sometimes enough to get it out. if not , add a little concentrated heat with a small torch tip.  i have gotten MANY broken bolts out of cast iron this way.  i know i could get it out and it's worth the effort to do it right

[Fordiesel69 267]

I only have a mig.  I never could TIG if my life depended on it.  It requires more skill than I have.

[305 380]

whatever you do , in my opinion it is worth the effort to get it out.... especially since you have some of the broken bolt above the block surface. i have got them out when it's below the surface. drill and re-tap is the last resort in my opinion.  even if you have to get someone else to do it

oh yeah......don't try an "easy out" , they are a joke

[pacer 3,175]

If it broke off because of over tightening then it shouldnt be too difficult to remove - try bumping it with a small very sharp chisel in the 'remove' direction, if it dont move pretty easily probably better abandon that method. I think the best method is to have access to a milling machine or heavy drill press and use a center drill to get a starting point for the correct size drill bit to more assure you dont get off center. The welded nut is also a viable option with sometimes the heat caused by the weld 'un-freezing' the culprit.

 

Whatever method you use, let us know -- hopefully successfully of course!!

[joel_400 59]

A trick I learned from a guy who works for lincoln welding is to weld a washer to the "stud" thats sticking out,then weld your nut to that. It does make it easier to penetrate whats left sticking out, and easier to weld the nut to. Just a thought. Good luck

Joel

[illinilefttackle 399]

Everyone has their own way-if I have one just above the surface-center punch it real good-put a bit in your air gun that has a pencil tip on it-then lightly zip it a few times ( really clears out corosion and rust from the threads) then chisel counterclockwise -Hope it helps-Al

[Fordiesel69 267]

Well, this brings me to decision time.  Machine shop will charge $60 per hour, and that is the minumum charge.  Used STD bore blocks on ebay are $70 shipped.  The bolt will not come out by welding a nut to it.  We also did weld a washer to it first, then the nut on top.  (awsome idea which definatly worked better)  We tried this 4 times, and the nut just breaks off.  This is where we may have made a mistake:  we welded the nut and while it was hot, tried to back it out.  Would it have been better to let it cool completely, and then heated the block with an acetelene torch around were the hole is?

 

We do not have any equipment to drill it, and I have never in my life had luck doing this on anything. 

[305 380]

that's why i use a tig welder..better penetration.   hard to get good penetration with short tack welds with a mig

[Fordiesel69 267]

Now off to find someone who can TIG.  This will be fun.

[Fordiesel69 267]

Last question before I scrap the block.  After I have this tig welded, can I use an acetalyne torch to heat up the fin area and the ex. port area to a dull red?  Will this ruin the block or warp anything?

[WH nut 553]

You really dont have to scrape the block just yet. Take and cut the bolt off flush now. Take an air chisel with the pin punch like mentioned before. Center the punch and rattle away. Start with a small bit and make your pilot hole. Now go bigger each time. After you get about an 1/8in hole rattle it again. With the hole, make sure you have drilled all the way through and the hole will relieve some of the preasure. After you get the 1/8in hole if you have left handed bits start drilling with those. You may get lucky and the left handed bit will grab and back it out. If that fails tthe you will be in a position to tap.

[can whlvr 993]

i would not drill it by hand unless you can ABSOLUTLY get the drill in the center,and i agree,dont use easy outs,they will break too.if you heat up the block try and disperse the heat,move the torch around the block,not just in one spot

[joel_400 59]

If you werent so far awy Id say bring it to me and I'll get it out...Ive been working at two different shops that do alot of exhaust work for a combined 15 years or so and have removed many broken exhaust studs in my time there. Even if you heat it red hot to get the bolt out you can always have the block decked at a machine shop to straighten it back out.

joel

[Fordiesel69 267]

Went to a friends sheet metal shop this morning, had him tig weld a washer onto the stud, then a nut, and it still would not adhere.  The grade of bolt or the metal is simply not penetrating.  I measured my drill press and the block will not fit under it.  I have no center punches or air chisel.  So off to a machine shop for one more try before I buy another block.  I am willing to bet that with it having a .010 over piston, some idiot cross threaded that bolt on the way in, and now it rusted and seized in place.  I beleive the machine shop will fail to get it out as well only because it has been welded on a total of 6 times.  That stud will now be "heat treated"

 

In the time spent traveling to places and labor for this stud, I could have rebuilt 3 of these in that time frame.

[rmaynard 15,927]

Never underestimate the ability of your local machine shop.

[buckrancher 2,694]

Never underestimate the ability of your local machine shop.

piece of cake!!!

Edited June 6, 2013 by buckrancher

[chazm 413]

 

In the time spent traveling to places and labor for this stud, I could have rebuilt 3 of these in that time frame.

 

 

 

Never underestimate the ability of your local machine shop.

 

Lesson learned ...

 

Chasm

[Fordiesel69 267]

UPDATE:  Dropped it off at the machine shop and they used a milling machine to get it out.  The top 3 threads did get damaged a bit, but he gave me a stud that went all the way down into the block.  So in my opinion it will work perfect this way.  With the stud being welded on, I think I made his life hard. 

[can whlvr 993]

i knew they can machine it out,so if you dont mind let us know what it cost so we know for the next guy

[Fordiesel69 267]

Not sure how much as he did other machining at the same time.  Most shops will charge a fee of like 15 per bolt up to 30.  And some shops charge hourly.  It cost 75 to get the head bolt out and to have the crank turned under 0.10.

[big mike 13]

Glad you got your block fixed.

You did not cause the machinist any undo harm.The bolt would have been annealed by the weld and cool process.The heat and cool cycle actually works to break the bond if it was rusted in so preheating the block would have inhibited the process.

[specialwheelhorse 174]

Check out Tap burners or metal disintegrators,  We used them in the aircraft industry

and many good shops around major citys will have one, They will burn out broken

studs bolts, drill bits,taps with no harm to threads if done properly. there is no reason

to discard a perfectly good block for a broken stud.

                                   Your OLD aircraft machinist      In Texas