Cylinder head with issues..

[T Batnes]

A cylinder head bought on Ebay a while ago, turns out to have a couple of issues after cleaning and bead blasting of old grit and paint.
Two of the rocker box bolt bosses have been welded up, and not by the best welder out there. The rocker boxes may sit tight, if I get threads in the holes, and maybe I can get the oil to stay put inside by using some epoxy/JB weld on the gasket surfaces before putting on the gaskets. But what worries me a bit, is a couple of vertical cracks that are present in both the nearby head bolt bosses. I could grind out a fillet on top of the cracks, just on the bolt landing, and fill it up with weld, to lock the crack from further expanding. What would you do?

[brenton.roy]

I'd use it as an opportunity to get the whole lot fixed properly. Grind down the shoddy welds and redo if necessary and have the crack fixed at the same time.

[T Batnes]

Yes, I was thinking about that too, and contacted a shop well known for fixing cast iron blocks, heads and such - just got their reply back now.... they are thinking 2 full days of work, maybe 3 including machining. Because they had to preheat, weld a little, hammer/forge the welded area, cool down carefully, preheat again, weld a little and so on. All to avoid new cracks to form. Tideous work, time consuming. And at £50 an hour, that sounds a tad expensive. Ah, another paperweight then...

[Vincent.vanGinneke]

see this thread : viewtopic.php?f=40&t=6601&start=20
It can be done but it takes a lot of time and Dremel bits

[T Batnes]

Great info, thank you! I will talk with a welder I know, problem will be to heat it sufficiently without a glass blowers stove I guess. We have acy/ox at the shipyard, and mig.

[JohnnyBeckett]

i would get it done properly because it has to be hot and arc ( stick ) welded with cast rods not mig and if you cannot get the face 100 % use high temp sealer

[brenton.roy]

I have wire welded a head with oxy. You just need to be patient.
Nothing to lose using Vincent's MIG method and plenty of heat via an oxy set.

[nevhunter]

They usually crack when cooling off after welding ,if you aren't careful to control the cooling.. TIG and MIG are very concentrated heat and you might get hard spots near the edges of a weld. That head will probably run OK if you leave it alone rather than spend heaps on it. Spot face it carefully and see how it tightens down. I doubt any piece will fall out or the cracks go anywhere. Use a hardened thick washer under the bolt head and spot face an extra amount off to maintain thread depth for head bolt.. Nev

[john.whiting]

looking at the welds ,its looking to me its been welded with pure nickle rod,so the weld shouldnt be hard,might be a hard spot where the arc has struck.......The secret of Vincent s method is heating the head red hot in a low oxygen furnace atmosphere.Then there is equalized shrinkage and slow cooling.....When I was working I used to regularly MIG weld steel cover plates on the hubs of cast iron wheels.Certain shapes of weld contain inbuilt problems ...the worst being long welds with free ends.A concentrated thick spot deposit isnt subject to excessive shrinkage stresses as it cools.......Anyway ,if you have doubts,braze the defects with a brass rod ,or even nickle bronze......Very high strength isnt needed,and the secret of braze weld is the deposit has low strength until way below red heat,so the bronze yields as it shrinks ,and doesnt stress the iron.

[nevhunter]

It's a lot easier on corners where stresses don't happen as much. Where that head bolt goes is getting towards the middle of the casting where there's more stress created. Why not give it a go as it is? Nothing's going to be damaged and if it works, it's ok.. You don't see it. That model has no head gasket. You double lap the joint. Do both surfaces then continue to lap the outer face a little. Nev