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I have a friend who got a used small engine block that he is wanting to use. The exhaust studs where broken off in the block, so he got into drilling out the studs. In his words " the drill bit really liked the aluminum more than the studs". So he contacted me to ask if I could weld up the holes and re-drill and tap the holes. I have a few questions about what I should from some of you more experienced guys.1. Should i pre-heat before welding, and what temp should I aim for?2. Should I take a carbide bit and open up the hole (taper) so I can get all the way down inside the hole to weld up the bottom?3. Would 4043 work well as the filler for a cast block?4. After I drill the holes would you recommend to put heli-coils in instead of tapping the aluminum?Thanks guys!Lincoln Precision TIG 225Hobart Handler 175
Reply:1. It's not necessary to pre-heat, however if you choose to do so, I wouldn't go any higher than 200-2502. If you can't weld from both sides, It's always better to weld from the bottom up. Depending on the dia of the hole, and how much material you have to work with around the hole, it may not be necessary to open it up further prior to welding. If the hole dia is small, and your area is restricted, then I would open the hole to help you get to the bottom.3. 4043 will work well.I see no need for the use of heli-coils if your weld is solid, but on the other hand, it wouldn't hurt.
Reply:Thanks ChgoWelder!!I have not seen the block yet, he called me at work today. I assume the holes are going to be pretty small, but we will see.Any suggestions on cleaning down inside the holes??Lincoln Precision TIG 225Hobart Handler 175
Reply:Ya better post some pics, this ought to be interesting....My name's not Jim....
Reply:lol will do If I'm not too embarrassed by the outcome!Lincoln Precision TIG 225Hobart Handler 175
Reply:I think some people would be interested in your friends work.
Reply:Originally Posted by dragr8cerThanks ChgoWelder!!I have not seen the block yet, he called me at work today. I assume the holes are going to be pretty small, but we will see.Any suggestions on cleaning down inside the holes??
Reply:Best plan would have been to weld a nut to the stud, but it sounds like it's kinda late for that. Cross your fingers and hope you can just heli coil it without welding. You said small engine so I am assuming 5hp-25hp. If so, you're looking at a 1/4" or 5/16" hole about an inch deep. Only way I would weld it would be with a spool gun and very steady hands. Don't quite know how you'd go about tiggin it without makin the hole huge first.My name's not Jim....
Reply:Originally Posted by dragr8cerI In his words " the drill bit really liked the aluminum more than the studs".
Reply:Alright guys, so I got to work on this a little late, I lost most of the day after work on friday because I went to pick up a new (to me) tool box. That can't be a bad thing right?I got the block and upon initial inspection didn't think there was much I could do. He told me he didn't have anything to lose so I took it. If nothing else it will give me practice welding on cast aluminum. The hole closest to the deck some how got very large. So large that a crack had propagated into the top cooling fin. The sealing surface to the muffler is also very pitted. This thing is just a mess!I do not have a spool gun for my mig like someone suggested, that would have been nice. I tried to extend my tungsten far enough to get to the bottom of the hole, but that just burnt up my tungsten! I decided that this block would probably not be the best for him to use in light of the crack, and also the cylinder condition. I did go ahead and weld up the holes the best I could, but will tell him I don't recommend using the block. I can't imagine the head will seal very well where I the material was so thin and I had to put so much heat into it.Here is the after pic, but I would not call it fixed at all!Lincoln Precision TIG 225Hobart Handler 175 |
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发表于 2021-9-1 00:34:15