10 replies to this topic

[Boab]

Is it possible to weld the outer wall of the cylinder head. My fault really, but all three bolts were the same size and I over tightened the outside one on the thermostat housing. Would be a shame to loose the head.

[Bungle]

It can be done BUT i dont know if it should be .

my grandad was a mechanic on the humber lifeboat during the war , and he use to tell me lots of storys of repairs to keep the boat going as there were no spare parts . like welding heads and blocks , reparing cracks in heads and all sorts of bodges .
There was one story that he had to replace the big end bearings at sea with the other engine running beside him to get the boat home , no wonder he was deaf .

[TimS]

thats mint, iv been on a modern humber lifeboat and the bowthrusters are 800bhp engines alone! the main supercharged CAT engines are loud enough to blow your ear drums

[Bungle]

my brother inlaw is one of the mechanics on the humber lifeboat now

see " hi i'm marcus "

[TimS]

chances are iv spoken to him then, a few years back when brian beven was the skipper there was a big party on spurn point which i was at! thats the only time iv been on the life boat but it was mint!

[dklawson]

Are you talking about a crack in/around a thermostat stud hole? If so, don't weld it, take it to a shop that can braze it. Afterward, have the head checked for flatness. Make sure you run a tap down the stud holes before building the head back up. Lastly, consider using stainless steel bolts (of the correct length) for the thermostat housing instead of the studs.

Welding cast iron is an art. It can be done with nickle rich welding rods, a lot of careful pre- and post-heating etc. If the damaged part of the head is NOT in the combustion chamber area, brazing is the prefered method of fixing cast iron.

[Boab]

You can just see the crack running down the front stud hole. Is it fixable??? It runs about 2 inches.

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[Boab]

and another

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•  mini_005.jpg   307.4K   3 downloads

[Boab]

and one more

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•  mini_007.jpg   355.19K   2 downloads

[dklawson]

Those are some big pictures. Sadly, they're a little fuzzy. From what I saw from the first picture, it looks like you have two cracks... but again, the pictures are a little fuzzy.

The outer crack can certainly be brazed. If I had to guess, I'd say you ran the studs too deep and they worked like a wedge to split the casting. This is a great reason to use bolts of the "right length" instead of the studs. After brazing, re-tap the holes with a bottoming tap. Then determine (by dry fitting the parts) what the maximum safe stainless bolt length will be. Cut the bolts off if necessary to get that length less about 1/8" [3mm]. Make sure all the tapped holes have the same thread depth and that all the bolts are the same length so it won't matter which bolt is in which hole.

What concerns me is what appears to be a second crack visible in the first picture. It looks like there is a crack started adjacent to the hole nearest the through hole for the head stud. If cracked, that one will be harder to fix without warping the head. Regardless, once brazed, the head should be checked and most likely shaved flat again. Expect it to warp a little.

[Boab]

What concerns me is what appears to be a second crack visible in the first picture. It looks like there is a crack started adjacent to the hole nearest the through hole for the head stud. If cracked, that one will be harder to fix without warping the head. Regardless, once brazed, the head should be checked and most likely shaved flat again. Expect it to warp a little.

Thats just the casting line. The crack you see in the 3rd pic is all there is.

Cheers DK, I will be asking my freindly welder guy to fix this for me. :grin: