How to fix this: Cast Aluminium Engine Mount

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Hi there, I'm refurbishing a motorcycle engine of a Honda ST1100 which  had a crash (there was also fire in the intake).  I want to repair the broken mounts, here is a picture of one of the cylinder heads:I already cleaned it with a wire brush, acetone, small Dremel wire-brush to geht into the threads. My next steps would be to pre-heat the head,then build up by AC-TIG welding finally machine the welded part, drill and tap the mounting hole.Do you have any tipps or suggestions for me?ThanksMaiki
Reply:I don't like 4043 to repair threaded holes as it tends to be too soft to support threads. I go 4943 or even 5356 if I feel thread strength outweights intergranular corrosion from high service temperatures. 4943 would be my first choice for filler.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:After you build it up, you shouldnt need to have it remachined. Some files and patience will clean it up back to normal. Most of my cast aluminum repairs are cleaned up with files when the application calls for "original appearance" like the sides of a carb tunnel on an intake.
Reply:Thank's for the hints, I was planing to use 4047, should be O.K.? I tried to get 4943, but somehow I can't get it in Germany. Is there also an EN ISO naming? 5356 I guess ist AlMg5 with some Chromium, I do have regular "AlMg5", 3.3548. Thought this is for regular aluminum, e.g. sheet metal.Maiki
Reply:Originally Posted by MaikiThank's for the hints, I was planing to use 4047, should be O.K.? I tried to get 4943, but somehow I can't get it in Germany. Is there also an EN ISO naming? 5356 I guess ist AlMg5 with some Chromium, I do have regular "AlMg5", 3.3548. Thought this is for regular aluminum, e.g. sheet metal.Maiki
Reply:Thanks so much! I'll go with the AlMg5. The engine will go in a hobby project, I want to build an off-road buggy.Maiki
Reply:After you build it up, you shouldnt need to have it remachined. Some files and patience will clean it up back to normal
Reply:if the threads are not strong enough, you can always use inserts. just make sure they are fit for use in ally.
Reply:Turn down an insert with a pilot hole.  Press fit insert into CLEAN hole.Weld with 5356.Drill / tap / machine to desired specs.Miller Dynasty 200DXMiller Spectrum 250DMiller Millermatic 200Bunch of old blue dinosaurs....