Aluminum head repair help?!!

[JavelinScott]

I have an aluminum head from a 1935 Studebaker. It has a crack  and some corrosion. Im wondering if it can be repaired, who can do it and if so how much?   

[JV Puleo]

Metal stitching is the only way to fix that. I would not even consider welding it. This has been discussed many times on this forum. Do a search. I recommend Frank Casey in Mass. He was resting a head when I was there a few months ago.

[Gary_Ash]

You can replace the aluinum head with an iron one. See this previous discussion:

 

[prewarnut]

OK someone school me:

1) can you really successfully stitch a head under those pressures/temp changes, etc and what would the success rate be? 

2) how do you stitch across the crack and then turn 90 degrees to go down both sides? One would be disrupting the vertical stitching with new horizontal ones....or would one not stitch horizontally - but what happens to the crack there over time?

[Paul Dobbin]

I have a early Ford V8 aluminum head with the same problem.   I had hoped to get it welded  and  resurfaced , but sounds like that doesn't work.  I guess I'll just bead blast it an make another piece of garage decor.   Then paint a cast iron head with aluminum spray paint.

[wayne sheldon]

Maybe I need some schooling? While cast iron heads are usually better served by stitching? I have seen quite a few aluminum heads repaired by welding. The key factor on aluminum heads (and other associated aluminum castings) being the quality of the aluminum used and seriousness of corrosion. Insidious corrosion can render even a nice looking aluminum head unusable, however, usually such corrosion can be seen at the water passageways upon close examination. In such cases where serious corrosion is evident, even stitching a head crack is pointless as the head will simply fail somewhere else soon after repair. 

Quite a few years ago, at a friend's machine shop (he was well known and highly respected for the quality of his work, both antique automobiles and racing cars), I saw a racing engine overhead valve head that he had spent a day welding back together after the dragster swallowed a valve and punched it up through the valve seat and port. He had completed the welding, and was just beginning to machine the port back to spec. His work didn't come cheap, I can only guess that the repair for that special head probably cost more than a ready to run new crate engine!

 

Actual welding of aluminum of course cannot be done in the open air. It requires an "inert gas" (the "IG" in TIG and MIG) to prevent the molten aluminum from literally catching fire and burning away. With the proper equipment and an experienced welder, and depending upon the specific alloys and quality of the casting, aluminum welds very nicely. Avoiding warpage is extremely important! Once properly done, a good aluminum weld should be as strong as the original casting.

Cast iron is a bit different. Again, the specific alloy is very important. Alloys vary greatly, and an improper mix of casting alloy and welding rod can be disastrous! Even with a nearly perfect match of materials, or a nickel based universal type welding rod, clean and even blending of materials is difficult. In addition, the heat required is so great (near 2000 degrees Fahrenheit!) that severe warpage becomes almost unavoidable! Attempting to pre-bend in reverse the object to compensate for the expected warpage will usually result in the crack expanding even larger, often to the point it cannot be welded if the crack grows to an inaccessible area.

If the welding materials are not a very good match, or for any reason do not blend well, the weld/repair can likely become so brittle that the item will re-crack just sitting on the table after it has cooled. Welding cast iron is a real specialty, an ability to recognize the materials and their reactions to each other is necessary, beyond the basics of metallurgy and basic techniques. I have successfully welded some cast iron myself on several occasions. I have also failed miserably on at least as many attempts. I know my limits and will not even attempt anything really valuable or usually for anyone else (I did once for a good friend, it came out okay).

 

Paul D et al. I am curious as to why some would blanketly dismiss welding an aluminum head without closely examining it. The softer aluminum may not take as well to stitching (done with small threaded rods) as does cast iron. The failure rate of welds in cast iron is high due to mixing problems and temperature issues. 

Any engine aluminum head more than a couple decades old may have serious corrosion issues inside. But that becomes a judgement call. A crack, in any location on such a head may or may not be in part due to corrosion. Again, a judgement call.

Any aluminum head run before about 1960 is going to be especially suspect for corrosion problems because anticorrosion coolants had not yet become common.

I certainly understand a generalization that aluminum heads on antique automobiles generally are not worth the effort to be welded. Most of them have suffered extensive corrosion inside the water jackets. Whether a crack, or a small hole poking out from the inside? Most repairs are soon followed by another failure. But if one does not look? How can one know. 

The final assessment should be done by the experienced welder that knows what he is doing, and can be trusted for his advice. Unfortunately, anymore, I don't know anyone to recommend.

[paulrhd29nz]

Before you do anything mic the thickness of your head , then find out what the minimum usable thickness is of the head you have. That is step number 1. The head you have may be milled below allowable tolerances. 

[JavelinScott]

Thank you to everyone who replied. I ended up going into the rabbit hole on that one. I guess my boss is going to make a wall ornament with it. I did have someone call and left a message. Unfortunately you didn't leave a call back number. I'm just getting into the old Studebakers and what an eye opener!. Thanks again everyone   

[46 woodie]

The biggest issued that I ran into when TIG welding aluminum engine parts is the porosity of the aluminum. I once tried to weld a crack in an aluminum oil pan and every time I applied heat, I could literally see oil rise to the surface contaminating the weld. The owner eventually took the pan to a place that serviced aircraft and they "hot vapor degreased" the pan but it still bubbled oil when I welded it.

[DavidMc]

I had a similar crack stitched on a cast iron Packard cylinder head some years ago, it failed in a very short time.  There was not enough thickness, due to internal corrosion, to hold the pins.  As suggested above have the thickness checked before making a decision.  

[Rusty_OToole]

 Some years ago I saw an article about the restoration of a 1937 Auto Union race car. The aluminum head needed repair, they consulted the experts at Reynolds Aluminum. They analysed the material and said, "this is the kind of metal we use for lamp posts and lawn furniture". In other words, the best aluminum available in 1937 was of very inferior quality compared to today's alloys.

Then there is the fact that aluminum deteriorates or loses strength more than iron or steel.

So, an old aluminum engine part is likely garage art unless it is an NOS never used piece. Even then it would be suspect.

Have also heard that all Duesenbergs had aluminum connecting rods, and a true expert wouldn't even try to start an old engine until they had been replaced with new steel ones. They are too likely to fail due to age and metal fatigue.

[DFeeney]

Another item to consider is , "How much is it warped?