shenion
Tool Pack Rat
- Messages
- 7,586
- Location
- Stone Mountain, GA USA
Forgot to do a "before picture". Was a 1" hole and a web of cracks (pushed out looked like a volcano where the connecting rod had blasted a hole:
Was a royal pain to do. Beside fighting oil contamination, the casting had lots of magnesium and probably some zinc. Try and lay a bead and lots of bubbles form. Was ground with a fresh wheel and then cleaned with acetone.
Filling the hole was a pain. I used 4043 wire as I have used 5356 in the past and it cracked when cooled. 4043 melts at a much lower temp than the parent metal. Made it real hard to lay a bead along an edge as the filler flowed like water before the parent metal began to fuse with it.
What I did was put a metal backer. It was probably 1/16" below the metal. Could not get it to fit well. There was pieces hanging down and curved (the bent out pieces were pounded back.) Then put big gobs of filler in. A few times I was able to lay filler along an edge, but it would bubble up so bad, I had to "boil it out".
Then at least 4 passes over the weld to get rid of pinholes. Grind flat and then lay beads over the pits. Founds some more cracks, I could hear it cracking when cooling. Seemed to always be in the old metal; probably cracks you could not see.
The final passes worked much better and there was less black soot (lots on first pass.)
Inside looks like crap:
One of the passes I forgot to put the backer in and was boiling/filling away pinholes and it sagged. So later passes caused tall sags as I was more interested in boiling out pits than worrying abiut globs on the back.
I think I'll hit it with a MAPP torch and see if cracks form.
If I had some 1/8" aluminum, it would have been better to cut a 2x3" hole and fit a new piece. But I did not want to remove the crank, heads, pistons etc to get good access (not my engine, doing for a buddy on the cheap.)
Been doing this several times lately. Would be nice to have some nice fresh clean aluminum to work with once.
Was a royal pain to do. Beside fighting oil contamination, the casting had lots of magnesium and probably some zinc. Try and lay a bead and lots of bubbles form. Was ground with a fresh wheel and then cleaned with acetone.
Filling the hole was a pain. I used 4043 wire as I have used 5356 in the past and it cracked when cooled. 4043 melts at a much lower temp than the parent metal. Made it real hard to lay a bead along an edge as the filler flowed like water before the parent metal began to fuse with it.
What I did was put a metal backer. It was probably 1/16" below the metal. Could not get it to fit well. There was pieces hanging down and curved (the bent out pieces were pounded back.) Then put big gobs of filler in. A few times I was able to lay filler along an edge, but it would bubble up so bad, I had to "boil it out".
Then at least 4 passes over the weld to get rid of pinholes. Grind flat and then lay beads over the pits. Founds some more cracks, I could hear it cracking when cooling. Seemed to always be in the old metal; probably cracks you could not see.
The final passes worked much better and there was less black soot (lots on first pass.)
Inside looks like crap:
One of the passes I forgot to put the backer in and was boiling/filling away pinholes and it sagged. So later passes caused tall sags as I was more interested in boiling out pits than worrying abiut globs on the back.
I think I'll hit it with a MAPP torch and see if cracks form.
If I had some 1/8" aluminum, it would have been better to cut a 2x3" hole and fit a new piece. But I did not want to remove the crank, heads, pistons etc to get good access (not my engine, doing for a buddy on the cheap.)
Been doing this several times lately. Would be nice to have some nice fresh clean aluminum to work with once.
. I guess I need to make a checklist of all the switches i have to change.