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Crankcase repair will leak?

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Alright so right now I'm rebuilding an engine but when I took it apart there was a little crack on the side of the sealing surface so I brought the case half to a welder and he did a great job but now I have a tiny little warp on the sealing surface where the gasket sits on. Can I fix it or do I need a new case?20170701_211445.jpg20170628_204110.jpg

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What you can do is bolt the two empty case halves together with the case gasket between them. Once lightly bolted together, hold a flash light on the inside up against where you think the gap is.. If you can see light from the outside, it will leak.

Like you, I sent a case half out to a local "professional" aluminum welder and got it back just like yours-with a gap that would leak oil. I then took that case to a 2nd guy who actually did it right, and got the sealing surface perfectly flat. Since that time I bought a TIG welder and I have welded several up and have gotten them perfectly flat when I was done so that just the dry gasket was all that was needed to make a perfect seal. Take it back to your welder and put a straight edge across the sealing surface and kindly explain that it is going to leak. The case gaskets will not crush that much so any flaws in the sealing surface could easily result in a leak requiring complete engine disassembly to repair.

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Yeah i cant see that sealing very well - will have to get it built up and leveled off

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What you can do is bolt the two empty case halves together with the case gasket between them. Once lightly bolted together, hold a flash light on the inside up against where you think the gap is.. If you can see light from the outside, it will leak.
Like you, I sent a case half out to a local "professional" aluminum welder and got it back just like yours-with a gap that would leak oil. I then took that case to a 2nd guy who actually did it right, and got the sealing surface perfectly flat. Since that time I bought a TIG welder and I have welded several up and have gotten them perfectly flat when I was done so that just the dry gasket was all that was needed to make a perfect seal. Take it back to your welder and put a straight edge across the sealing surface and kindly explain that it is going to leak. The case gaskets will not crush that much so any flaws in the sealing surface could easily result in a leak requiring complete engine disassembly to repair.

I will try the trick with the flash light today
Yeah i cant see that sealing very well - will have to get it built up and leveled off

How do I get that repaired?

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20170702_094841.jpg I put the case halves together and there's a gap between the cases I measured it with a feeler gauge and the gap at it's largest point is .009 inches Idk what to do now. Tomorrow I'll go get my cylinder back from the replating shop and I think I'll bring the case with me and ask them if they can fix that.

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Just had local welder fix this one recently.  Done this few Times now. I have him fill and fill beyond so then I grind and file. Get a good file and can also use the file as a sraight edge :thumbsup: first pic he sent me rest I took. Last is done and bike rips. Yours isn't that bad

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That's exactly what I plan to do that's my last option I talked with a shop that repairs engine and they said that it cant be fixed but sure is it can be done

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17 minutes ago, jackstrap said:

That's exactly what I plan to do that's my last option I talked with a shop that repairs engine and they said that it cant be fixed but sure is it can be done

Ya man. Just follow the curve so crank halfs don't hit. I use a grinder with worn down wheel.  Don't recommend tho for everyone

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Ya man. Just follow the curve so crank halfs don't hit. I use a grinder with worn down wheel.  Don't recommend tho for everyone

That's not an issue for me I've been using power tools a lot I'll grind the excess with it and then finish the job with a file
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1 minute ago, jackstrap said:


That's not an issue for me I've been using power tools a lot I'll grind the excess with it and then finish the job with a file

:thumbsup::thumbsup:

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if it was mine id have the effected  area built up more than needed take to a machine shop and have them mill the surface back to original  much more accurate than a hand held file it might cost a bit more but what will a new case cost? good luck hope you get it fixed.

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That will leak.  But a proper fill job and then PATIENCE with a grinder and file and it will be fine.

The welder grinded the case and he did a terrific job but the welding itself was excellent. I'll go to another welding shop but that time I'll be grinding it myself.

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On 02/07/2017 at 11:27 AM, vicxr400 said:

if it was mine id have the effected  area built up more than needed take to a machine shop and have them mill the surface back to original  much more accurate than a hand held file it might cost a bit more but what will a new case cost? good luck hope you get it fixed.

Problem with a machine shop is that the milling machine has to make a "0" on the part to line it up but that "0" can remove a couple thousands of an inch which is in no case wanted.

 

Edited by jackstrap

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6 minutes ago, jackstrap said:

Problem with a machine shop is that the milling machine has to make a "0" on the part to line it up but that "0" can remove a couple thousands of an inch which is in no case wanted.

 

Hence the extreme patience with grinder and file.

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Just now, jackstrap said:

Problem with a machine shop is that the milling machine has to make a "0" on the part to line it up but that "0" can remove a couple thousands of an inch which is in no case wanted.

 

Get a better machinest!

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11 hours ago, jackstrap said:

Problem with a machine shop is that the milling machine has to make a "0" on the part to line it up but that "0" can remove a couple thousands of an inch which is in no case wanted.

 

not necessarily, and a gasket will handle a thou, but not 10 thou like a grinding hack job

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not necessarily, and a gasket will handle a thou, but not 10 thou like a grinding hack job

I agree but still I will do it myself

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I agree that you can file finish it yourself once you get it welded again. The aluminum after welding is very soft so it does not take much to get it filed flat. Just be very careful that you don't file out too much. With a rough file, it should not take much work at all to get it really close. I like to use a low grit sand paper on a flat backer board to keep it perfectly straight. Get it close with a file-with a ridge maybe .060" high still, then start with 80 grit on a backer board and work it until you get it closer to .020" or so above the rest of the case, then step up to 120 or 180 grit again on a backer board and keep filing until it is perfectly flat. Or, if you feel really confident with the file, just take it down closer to .010" or so, and then finish with sand paper. This is not rocket science so don't let anyone tell you that you can't do it. Just do the flash light trick when you are done again.
 

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I agree that you can file finish it yourself once you get it welded again. The aluminum after welding is very soft so it does not take much to get it filed flat. Just be very careful that you don't file out too much. With a rough file, it should not take much work at all to get it really close. I like to use a low grit sand paper on a flat backer board to keep it perfectly straight. Get it close with a file-with a ridge maybe .060" high still, then start with 80 grit on a backer board and work it until you get it closer to .020" or so above the rest of the case, then step up to 120 or 180 grit again on a backer board and keep filing until it is perfectly flat. Or, if you feel really confident with the file, just take it down closer to .010" or so, and then finish with sand paper. This is not rocket science so don't let anyone tell you that you can't do it. Just do the flash light trick when you are done again.
 

I just called a local machinest today and he was asking 40 bucks to do the job so I decided to bring him the case to machine it and get a true flat surface. It's also a good thing as I'm working 60 hours a week and prefer to take it easy during the weekend.
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