As the title states, what alloy of aluminum should be used when welding a Honda head?

 

TIG Welding Aluminum Heads - Engine Builder Magazine

 

Thank you, that's very helpful, has all the info I could want to ask and then some

 

they use 356 alloy in their castings. Ive used 4043 filler and it seems to work well. that is a good link and probably covers everything i only skimmed it. pre-heating is your friend but i usually go to 250*F. at 350 you are starting to effect the aluminum too much and if you were to keep it at that temperature for a long period of time you would definitely warp the head. also, it's also a good idea to have something flat and straight to work on, not sure how possible it is to warp from the actual welding the head but it's always a concern of mine. I would use a 1/8" tungsten regardless of whether or not you are at 200 or 250 amps. he covers a lot of good welding basics but if you're not already a comfortable welder then the cylinder head is not the place to learn. keep in mind valve seats need to be replaced after if you go near the chambers

 

replaced? or cut? I know the heat can unseat them and/or warp them a bit, but as long as they stay fully seated I'd imagine just a fresh cut would suffice, no?

 

even if they appear fully seated there is no way to know they aren't going to move after seeing such excessive localized heat. for the cost of replacing the seats compared to just a valve job i would replace them every time on a welded head, especially considering at that point its likely the valves and guides are being replaced at that time anyways.

 

ok, well on that note, where can you buy new seats? or do they have to be custom made?