Welding steel to cast iron head?

wrote:


Tigging with stainless actually would make a better job if you had a peice of cast to make the repair with, but this is not a terribly high load application. I'd have been tempted to just build up the damaged area with Stainless rod and grind it to fit, myself.

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What's that Lassie? You say that Gunner Asch fell down the old sci.engr.joining.welding mine and will die if we don't mount a rescue by Tue, 14 Sep 2010 23:44:03 -0700:

I think I would braze it. But that would mean striping it down to pre-heat the casting. If you go this route, I recommend wetting out the brazing on both mating surfaces first, then clamp lightly together, cool slowly.
--

Dan H.
northshore MA.
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Gunner, if you don't feel that welding the insert to the valve cover is feasible, then how about this? Fabricate and weld a holding device to the valve cover, keeping the insert in place. IOW, the little repair piece can't fall out unless the valve cover is removed. Just remember that it's there next time you adjust the valves, so you don't lose it.
The idea of disassembling the head and preheating it for brazing sounds like a BIG PITA.
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On Thu, 16 Sep 2010 00:14:47 GMT, snipped-for-privacy@privacy.net (dan) wrote:

Coming from an era when the repair, or attempted repair, of cracked engine block and heads was common, I'd advise using caution in attempting to braze an engine head as it can result in further cracks. Companies that were most successful used an oven to preheat the head/block and IIRC got it hot enough that the oil, which was soaked into the cast iron, burned out. Usually quite a long preheat also, maybe 6 - 8 hours. After welding or brazing a post heat was done for about the same time. All this cost a fair sum, in those days and alternate methods were devised to repair cracked engines.
One method was to drill and tapered holes (pipe tap) to fill the crack. Each hole overlapped the previously installed plug. Cheaper and often times successful.
There were also methods which called for grinding the cracked area clean and coating with some sort of cement which was also occasionally successful.
All in all, not a trivial sort of repair.
Having said all that I have seen a Chrysler V-8 head TIG welded. A crack that ran from valve pocket to valve pocket. The weld was successful.
Cheers,
John D. Slocomb (jdslocombatgmail)
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TIG braze it with some Silicon Bronze filler.

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On Wed, 15 Sep 2010 23:09:36 -0700, Ernie Leimkuhler

I snagged a single stick of Evadour? Silicon Bronze today down in LA. Couple old 'uns who run two different welding shops were in my favorite welding distributor (Sims-Orange, Santa Ana) and thats what they suggested, using tig.
Ill do it this evening and report tonight.
Thanks all
Gunner, just back from 3 days in LA
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