Johnson 55. Can this broken stud be welded?

[steviecops]

I've removed my head cover to replace thermostat, but one of the bolts broke in the cylinder head. The stud is almost flush with the head, as you can see from the picture. Can I get someone to mig weld a nut onto this so that I can remove it?<br /><br />A neighbour has a mig welder, but doesn't fancy his chances of success. He says that he's scared that the heat from the welder might melt the aluminium head. Is it safe to use this method that close to the head? What you can't see from the picture is the engine cowling, which comes above the broken stud, so drilling it out isn't an option.<br /><br /> pictures <br /><br />Just as a matter of interest, the second picture is of the old thermostat alongside the new one. Out of curiosity, I tetsed the old stat and it worked fine, but as you can see, the little disc has come off, so there was nothing to stop the water flowing through the stat! There was no sign of it antwhere under the head cover, so it's either rotted away, or it is somewhere in the cooling circuit. I hope it doesn't cause any problems!<br /><br />Any advice on the broken stud would be appreciated. I was hoping to spend tomorrow getting it out.<br />Thanks<br />Steve

 

[G DANE]

Re: Johnson 55. Can this broken stud be welded?

Hi Steviecops<br /><br />I have done the first 15 - 20 removals of stuck bolt by TIG Welding. I would not be concerned of the one you got. The flame will only seek the steel and not harm aluminium. I have never MIG welded them, but a friend of mine has. Start by building a drop on top of the broken piece. Allow alloy to cool down between weldings. You will be surprised how fast the aluminium distributes the heat. I would end with welding a nut to this one. Let everything cool all the way down before unscrewing.

 

[steviecops]

Re: Johnson 55. Can this broken stud be welded?

Thanks G Dane<br />I've read many of your posts on the subject and I know you have had great success with this method.<br /><br />Could you tell me the difference between TIG and MIG welding please?<br /><br />Also, my neighbour with the MIG welder suggested using a spot weld. He said it would be easier. I know nothing about welding, so what is your opinion on this?<br /><br />Thanks again<br />Steve

 

[Solittle]

Re: Johnson 55. Can this broken stud be welded?

Steve - Were it mine I would take it to a machine shop rather than give it to a neighbor who is unsure of what he is doing. Could save you a block.

 

[Hooty]

Re: Johnson 55. Can this broken stud be welded?

SoLittle's got the hot ticket. Remove the head (no big deal) and take it to a machine shop.<br /><br />c/6<br />Hooty

 

[G DANE]

Re: Johnson 55. Can this broken stud be welded?

Hi again Steviecops<br /><br />What Solittle says, if your neighbor feels unsure, maybe he´s the wrong guy. <br />TIG welding is by a flame created between a wolfram electrode and ground. Welding material is applied from melting a hand held stick. Similar to the old Acetylene welding, just electric, <br /><br />I forgot, the best weld to the broken stud you have, will call for a roll of stainless welding wire, which he maybe hasnt. It all depends of how experienced he is, using his welder. Some people who has one, barely knows how to use it and pick the right power level. That being said, I'm no expert at all, just looked at others welding and tought myself. I´ve never had any problems with the broken bolts I god outthat way. But a couple of the ones I drilled out, ended some off- center, new thread was partly in broken bolt. But that worked too. It you chose to drill it out, file it flush first, use a mark to make a starting point and start by using a small drill. Be carefull not to break drills, or you will have a new problem, tried that too.

 

[steviecops]

Re: Johnson 55. Can this broken stud be welded?

Thanks for the advice guys, I wish I had seen your comments before just now <br /><br />Well, we went with the MIG welding, but as G DANE says, my neighbour didn't have a roll of stainless wire, and didn't have a lot of idea about how to use his welder. However, we gave it 3 attempts without any disasters, but each time, the weld broke <br /><br />So in the end, I decided to take the head off to get at the stud. Once I'd dropped the lower engine cover so that I could get the head bolts out, I discovered that with the cover dropped I could just get at the stud with a small drill. <br /><br />So I ended up drilling the stud out very slowly and carefully, and inserted a heli-coil. <br /><br />So, with the welding, removing air silencer, starter motor, throttle control cable, exhuast cover, dropping lower engine cover, shopping for heli-coil, drilling, then re-assembly, it took me all day to arrive back at where i would have been had the bolt not broken off. <br /><br />Still, at least it's done now and I'll be able to get at my thermostat easier next time.<br /><br />Thanks again for the advice.<br />Steve