Welding a nut on to Cylinder head bolts

[Markie93]

I’ve been having a load of hassle remove cylinder head bolts from a 20 year old jet ski that are corroded with white powder.

I’ve managed to remove 7 of the 12 with a propane torch and a lot of Patience. Tightening and loosening working it slowly to remove them however five of them broke as they are E12 head and not ideal for putting high torque/repeated load through them. Unfortunately they are snapped at the head and the bolt is flush with the cylinder head.. but due to the corrosion hold the head to the bolts I still can’t remove the cylinder head !!

I have bought a small/cheap gasless MIG welder on the highest heat to weld a nut onto it but unfortunately I can’t seem to get a good weld.

Has anyone got any suggestions? Whether I try and source a larger MIG welder or is TIG better?

The cylinder head is aluminium and the cylinder head bolts I think is a steel alloy but not 100%

 

[Wozzaaah]

I have bought a small/cheap gasless MIG welder

Welcome to the forum.
I would say therein lies your problem.
That process usually works very well but you really need to get a lot of heat into it to get a good, strong weld between the nut and the broken bolt stub. What welder did you waste your money on buy?

 

[Markie93]

Welcome to the forum.
I would say therein lies your problem.
That process usually works very well but you really need to get a lot of heat into it to get a good, strong weld between the nut and the broken bolt stub. What welder did you waste your money on buy?

I bought one same as below link from Facebook for £100 and it was still in the box apparently only used once. I do have an interest in basic welding. I did some in college and work in the shipping industry but by no means know anything significant about it ..

I noticed when I could get a decent weld to the nut but not bonding to the cylinder head bolt. Possibly because the cylinder head is supposed to dissipate heat ‍

Clarke MIG103NG 90 Amp No Gas MIG Welder - Machine Mart

www.machinemart.co.uk

 

[Cobbler]

I would think with that welder you have nothing like enough heat to get a decent bond between the nut & stud, let alone get enough heat to travel down the stud & free it.

 

[Screwdriver]

I reckon you're on a hiding to nothing. Sounds like a nightmare scenario. If the bolt head sheared off, you are unlikely to create a stronger connection with a weld.

So you really need to get that head off and probably the only way will be by chemically dipping it to reduce corrosion, give it lots of time. Then as many heat cycles as you can, get it hot, let it cool, repeat. Then knock the head off with a soft blow mallet.

This is assuming the head is stuck by corrosion and not by any remaining part of the bolt fixing.

 

[Puglet1]

I had a similar problem with a 35 year old VW Camper van whereby the exhaust studs had snapped.
I saturated them with plus gas for a few days but it didn’t seem to make much difference.
I have a very good mig welder and welded nuts to the sheered studs but a couple of the snapped bolts still wouldn’t undo.
I ended up heating the stud hole area in the aluminium cylinder with Oxy acetylene before I was able to release the broken studs.
I see you are in Portsmouth which is too far for me to offer help.

 

[8ob]

I bought one same as below link from Facebook for £100 and it was still in the box apparently only used once. I do have an interest in basic welding. I did some in college and work in the shipping industry but by no means know anything significant about it ..

I noticed when I could get a decent weld to the nut but not bonding to the cylinder head bolt. Possibly because the cylinder head is supposed to dissipate heat ‍

Clarke MIG103NG 90 Amp No Gas MIG Welder - Machine Mart

www.machinemart.co.uk

Try welding a washer to the top of the stud first, you can be sure of getting a decent weld on the entire surface of the stud/washer without damaging the head, you can then weld a larger nut to the washer. Might also pay to spend a few days teasing some plus gas on them before you start.

Bit like this but add a nut

 

[500e]

You could try Citric acid, build a dam with plastacine around the stud to hold the citric in place, remember it will eat alloy keep an eye on it.
When we did the old Scammell Scarabs they suffered from the same sort of problem, at the time you could buy deep circular cutters that looked like a tubular hack saw blade fitted over the stud, a wonderful tool.
You could hang the whole machine from an adapter we made that screwed a plate down on the plug holes, pour easing fluid heat and cool for a week or more not a bit of movement and that was cast head, 1/2 hour with the cutter off.
Cant remember where they came from though think there was 4 sizes

 

[Puglet1]

You have a couple of fantastic tips from 8 on and 500e.
Listen to guys like this and I’m sure you’ll succeed in overcoming your problem.

 

[dan treg]

try and upload some pictures of your item but think you need more heat/penetration

 

[Pigeon_Droppings2]

Isn't there some magic liquid that will dissolve the steel bolt but leave the Ali head untouched?

I'm sure I read someone on here had done it?

 

[PhillipM]

A few of the nastier acids, but you usually need to accelerate it with electricity too, and even then it's slow. I've burnt stuck bolts out of aluminium brake calipers like that but it takes days.

 

[Onoff]

Seriously this.....

Can you drill a hole in them to get an easy out in?

If so, do so. Then heat the area and rub a candle over the face of the broken stud. The heat causes expansion and allows the wax to get down in the gap. Did this on my ali Peerless mower gearbox.

 

[Erie Fred]

I had to weld one that broke off down in aways, was instructed to use stainless rod.
The flux made a thick black slag that kept the weld out of the threads.
Washer on top, and then add nut.

 

[bricol]

Whenever I hear anyone mention "easy out" I run away and hide!

 

[Onoff]

Isn't there some magic liquid that will dissolve the steel bolt but leave the Ali head untouched?

I'm sure I read someone on here had done it?

If you can keep an alum solution on the boil in a big enough aluminium pot I think.

 

[graffian]

If you can keep an alum solution on the boil in a big enough aluminium pot I think.

I tried using alum to remove a broken tap, face of tap fizzed a lot but after an hour or so of being submerged in almost boiling alum solution it didn't look at all altered.
I ran out alum at this point, I was adding more alum every time I had to add more water. So I gave up on it. I still have the dish it was in, it's identifiable by the thick layer
of alum in it. I guess there is a whole box of it in that pot.

I removed a few taps, including a broken roll tap without flutes, from aluminium using battery acid and a battery charger. Think of it as anodising.
Last thing I removed with battery acid was an injector. A specialist diesel garage gave up trying to remove it and told the bloke to take the head to a
machine shop or get a new head, he took it to the machine shop they suggested and they snapped a long mill in the injector!
So I got a free head. battery acid burnt the injector out.

 

[Morrisman]

Whenever I hear anyone mention "easy out" I run away and hide!

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

 

[KimB]

Given that you said it’s galvanic corroded to the cylinder head. I doubt you’d get it out with only welding to the cylinder head bolt. I do wonder if heat and then using a wax to fill the hole would help (as someone else mentioned). Also maybe a bit of hammer time with a mallet on the cylinder to see if you can break it free.

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.

 

[winchman]

The only thing I would ad is I have in the past made a jig to guide the drill in when drilling bolts out to ensure its kept square, its also worth investing in a good quality left had drill bit as these are much better for this application.
If you snapped the stud I doubt an easy out etc will shift it without a lot of Plus gas then heat etc first.