TIG welding an aluminum head INSIDE the exhaust port ?

Ok, experts, I have an interesting problem with the aluminum
head on my Toyota 22R engine (233K miles). It has developed
a small hole (.080 ?) from the water jacket into the exhaust port
about an inch in from the edge of the port. I assume it is a flaw
in the casting - I can go in with a probe and it seems to be
solid around the hole. Is it possible to get in there with a tig
welder and weld the hole back up ?? I suspect this is one of
those "you only get one chance" things ... Ernie ?? It is
definitely not a crack, just a small hole (on the other hand, the
water "cooling" of the exhaust manifold has left me with a
2+ inch long crack -- I may try to grind/braze that myself.
Other than that, the head is in good shape. Sigh.
Reply to
Mike Fields
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On Sun, 30 Oct 2005 17:46:22 -0800, "Mike Fields" wrote:Not a welding expert by any standard but I do repair cylinder heads. Yes it can be welded, requires a really small head on the torch and practice. Now for the answers too the questions you didn't ask(G). It was probably caused by galvanic corrosion from not keeping the cooling system serviced properly. Check all the other water ports on the gasket surface of the head for corrosion trying to eat it's way under the sealing ring on the head gasket( a really common failure on 22Rs) before having the pin hole repaired. If you find any other potiental problems have them all repaired at the same time. Lamar
Reply to
wbutler
I have a similar problem on an Volksie air cooled head. Small crack around the exhaust guide boss. I tried to use HTS-2000 with a MAPP torch but couldn't get it hot enough. I don't want to scrap the head :( The head is going to college with me tonight for my instructor to look at. I shall keep you posted. I'm surprised Rob hasn't answered this for you. I have been waiting for his comments.
Reply to
Balders
Put the head in your oven to preheat it. Dont keep trying to work on it cold.
Reply to
cl
Thanks for the response -- I will double check, but I don't think it was corrosion (I usually change the 50/50 antifreeze every couple of years). I will look at it more, but I did not see extra corrosion. I will go back and check it again soon -- you are right in that if that is the issue, probably better off finding another head. Oh bother ...
mikey
Reply to
Mike Fields
Thanks for that. Unfortunately my tutor said it was a no-go situation. Grrr. The bear about it is I had just ported both inlets and the other exhaust port before I spotted it.
Reply to
Balders
Looks like the same for me -- looking at several areas around the water ports and after having the machine shop look at it (they have seen a number of these before), it looks like a new head ($500 or so). They say a number of people have tried to solve these but are generally not happy with the results by the time you grind the hole out and find the next one ...
Thanks for the feedback people. mikey
Reply to
Mike Fields
On Fri, 4 Nov 2005 14:44:53 -0800, "Mike Fields" wrote as underneath my scribble :
Is the use of HT epoxy injection plus perhaps a taper peg worth examination for a pinhole in a water temp controlled casting? You might get away with that for some years - especially if the pinhole has a decent runlength! Charlie+
Reply to
Charlie+
Thought about that, but after looking closer at the passages as others here suggested and talking to the local machine shop I have worked with before, came to the conclusion there may be other spots ready to go through and it was probably not worth it to just have it happen again. New head should be here in a couple of days or so. My first thought had been duct tape ... ;-)
mikey
Reply to
Mike Fields

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