Welding a nut on to Cylinder head bolts

[ms08]

Might be helpful? I am doing my 9000 exhaust manifold gasket. Have one broken stud but expecting more though going to use plus gas etc first and offer up a small prayer.

https://www.uksaabs.co.uk/UKS/viewtopic.php?t=179124

Video has gone but suggestion using alum might help.

 

[carbonarc]

Is it possible to weld short hex. head bolts to damaged studs and allow use of a [Hired] induction heater to get heat and expansion into the studs?

 

[Migmac]

We had a jet ski that someone else had stripped everything off. The engine was untouched, we found out why, exact same issue as you have. We sold it on, it was meant to be a fun project for us! All I could see was hassle and grief. We now have a rather large outboard in our garden to tidy up

 

[PhillipM]

The first thing to try tbh would be heat the bolts with a torch first before trying to weld them if you don't have enough power with the mig. The heat and cooling cycles might help free the head too.

 

[dave h 2]

Find someone who does spark erosion (EDM) near you

 

[Kram]

Stick welder would have been much easier as a beginner I would say. Set the rod on the hot side to get a lot more heat in.

Alum does work but is extremely slow and needs to be kept hot which often impractical.
Electrolytic disolving can work bht again not easy to set up.

Any photos? How big is the engine? Drilling by hand is generally a bad idea unless you know what your doing. I've done it on easier items, and I've messed up a cyl head trying it too.

 

[Jelly_Sheffield]

Drilling is an option but if you get slightly wonky you’ll damage the head. If you were to try that I’d die grind a flat spot on the bolt and then use a centre punch to help start the drill.

Even with those precautions I would still use a drill guide to avoid the bit wobbling about, and if at all possible get the whole engine on the mill or drill press (more practical with a jet ski, as compared to a van).

 

[Gareth J]

Jet ski, aluminium and steel, snapped bolt head. Screams that it's so corroded as to be a be straightforward weld on nut situation.

If by drilling you could remove the head while still having a chunk of head bolt visible out of the block to enable you to get that part out too, I'd give that a go. If the bolts are not hardened too much by the welding you've already done. A die grinder may get you into unaffected bolt. Be careful though, if (when?) you veer off course, the Ali head will put up no resistance a be quite happily chewed away at by the off course drill.

Think that unless you have some big heating kit, trying to get it hot enough to do anything useful will be a hiding to nothing. The aluminium will be such a massive heat sink.

You could just persevere with the welding method with a bigger welder. It often takes several goes when I've done it. That said, the only time I've failed with it was a long, 1/4" fine thread in an aluminium outboard leg.

 

[8ob]

Many moons ago I made a thick steel plate/puller for lifting v12 Jag heads off ( they were a pig for corrosion), this plate bolted to every spare tapped hole/lug on the head and there was a threaded hole in the plate where a bolt could be wound down directly onto every head stud. that worked well but it was still a days work per head to gently warm and progressively lift a stuck head up the studs. others would fly off.

Bob

 

[500e]

Same sort of thing we did Bob, but the darn things would not move, and only the plug holes.
A fitter for BRS told me about the cutters as it was a problem they came across, good truck for local work we had a customer who hauled chickens about 8 miles from hatcheries to Chuke sheds, 20 trailers and 5 mech horses if my aging brain remembers OK.
The times I got out to see where the front wheel was pointing

 

[Markie93]

as you can see in the photo, the bolts I rounded I ground down in an attempt to be able to pry the head off but it’s stuck solid.. I don’t have great access above the engine so my only two options are to try and weld a nut and heat to high heaven or lift the engine out (lifting eyes in the spark plug holes as per the manual) try to use the weight of the engine to pry the head off..

 

[CompoSimmonite]

I had similar problem with a Reliant cylinder head bolts - nearly 50 years ago ! In the end the alloy had such a grip on the bolt that nothing worked and I ended up cutting the head away from the bolt so at least block could be saved (I'd got spare head).
If I was in the same position today I'd find some thin wall tube that JUST fitted over the head bolt and cut some teeth on the end before hardening them. Either using a drill or even a "tommy bar" I'd then use it to cut down the alloy. As there will be a slight difference in the head bolt hole and the bolt then such a snug "cutter" isn't going to eat much of the head alloy.

 

[Screwdriver]

as you can see in the photo, the bolts I rounded I ground down in an attempt to be able to pry the head off but it’s stuck solid.. I don’t have great access above the engine so my only two options are to try and weld a nut and heat to high heaven or lift the engine out (lifting eyes in the spark plug holes as per the manual) try to use the weight of the engine to pry the head off..

View attachment 459619

You want to take the head off in situ! Good luck with that!

If a stuck fitting has started to give me grief, I'll take a step back and give myself the very best chance of saving the situation and go stright in with the tactical nuke. I.e. the very best possible chance for success.


After seeing all the responses, I'd say the best bet is a puller as described by @8ob, that hadn't occurred to me but it sounds like a great idea.

First thing I'd do though is double check to make sure those aren't shoulder bolts. The remaining stud looks surprisingly large diameter and they can sometimes be a shoulder or waisted so that the head is still effectively retained.

Once you establish the bolts are not still clinging on to the head, I'd personally be going at it with a dead blow mallet with some tension separating the head from the crankcase, also hitting it with heat. You don't say how you are attempting to pry the two apart but there are few places where that is wise and plenty where you'll end up destroying the critical sealing face on both parts!

Tbh, you really need to get that engine on the workbench. Doing it in place is just making things ten times more difficult and there's a good chance you'll have to pull it out anyway....

 

[ajlelectronics]

When I was working on Reliant 850s, I used to fill the spaces around the studs with ATF/Acetone magic releasing fluid and then hang the whole car off the crane by the head assembly. One Rialto took nearly a week but eventually it gave up the fight.

 

[Ubique]

When I was working on Reliant 850s, I used to fill the spaces around the studs with ATF/Acetone magic releasing fluid and then hang the whole car off the crane by the head assembly. One Rialto took nearly a week but eventually it gave up the fight.

Similar with TD5 injectors, soak & hang from an engine crane overnight - occasionally chain a spare rear axle to the front bumper & repeat...

 

[Melvyn Best]

When I was working on Reliant 850s, I used to fill the spaces around the studs with ATF/Acetone magic releasing fluid and then hang the whole car off the crane by the head assembly. One Rialto took nearly a week but eventually it gave up the fight.

Had to do the same on a few Truimph 2000s 50 odd years ago. Had to take the head off a Peugeot motorhome about 5 years ago that someone had supposedly rebuilt the engine on and wondered why it kept breaking rockers when revved, 3 of the Torx headed head bolts stripped the splines . Drill bits wouldn’t touch them nor a burr in a die grinder, ended up removing the engine and cutting through the head and the head bolts to get the head off.

Looking at the photo of the engine I think I would try grinding the remains of the head off with a grinding burr in a die grinder

 

[bricol]

I would think those studs are corroded into that head all the way down - I don't think you are going to get that off without a machine shop.

 

[bricol]

A sure fire way to add hardened steel to the stud or bolt you then need to drill out completely…..

I've never understood why snapping say an M10 bolt due to it being seized, means that drilling it and then wellying in a smaller dia, harder, more brittle bit of steel and expecting it not to snap too is such a common practice.

 

[addjunkie]

Those bolts will be stuck all the way through the head. Id drill them into the head and soak them, fora week or so and have another go.

If that doesnt work, take the engine out, set up in a big drill press and drill them right through carefully, you will only get one go!

 

[ajlelectronics]

I've never understood why snapping say an M10 bolt due to it being seized, means that drilling it and then wellying in a smaller dia, harder, more brittle bit of steel and expecting it not to snap too is such a common practice.

Quite, but I suspect that was not the manufacturer's intent for use. They do come in useful from time to time, but not in a seized fixing as you say.