Crack in a AS41 case

[Leatherneck]

Put in a new cam, lifters, bearings throughout,redid a couple fittings and guess I got carried away with the tightening and cracked the case. Any ideas or do I have a new fire starter?

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[turboblue]

We have had cases fixed that were cracked front to back but not left to right.
I have a shop that does an excellent job TIG welding magnesium and were able to repair them.
Have one we just tore down where that had happened to it.
Take it to a reputable welding shop and run it by them.
JB weld and other chemical fixes don't usually work.

[Steve Arndt]

Grind the crack out and TIG weld it. It will probably cost around 100 bucks at a welding shop because it takes a lot of prep and cleaning effort to get it ready.

1:45 in this video actually shows a vw case.

http://www.weldingtipsandtricks.com/wel ... esium.html

[BAJA-IT]

I cracked my case like what turbo showed and Blackline Racing here in Salt Lake welded it for me. Don't remember what they charged though.

[Leatherneck]

Going to bring it to a machine shop, sent him a pic he said might have to fill it in then drill and tap it. IF that is the case I'm going to try JB weld first, if that doesn't work I will have to break the case back down .Thanks for the info guys, after all the work I put into it to find this I was close to making it a scrap pile of parts.

[Marc]

JBWeld lacks the tensile strength to stand up to the separation force exerted by the tapered pipe thread. If you want to give it a try, grind out a shallow notch along the crack to increase the contact area. A tiny hole at the end of the crack wouldn't be a bad idea either, at least if you think you can stop short of breaking through. Clean the area (and the threads) spotlessly. Acetone (nail polish remover) if you've got it, or hot water/detergent...gotta remove all traces of oil. When you put the fitting back in you won't be able to crank it in tight enough for the threads to seal; run it in as far as it'll go by hand, counting the turns, then remove it and coat the threads with JBWeld or epoxy and screw it back in to the last turn where it lines up that's short of the initial count. Given clean threads and sufficient cure time, you might get away with it.

[Ol'fogasaurus]

Leather, I agree with Marc; JB weld is a good strong product and,with the area properly cleaned and the end of the crack drilled to stop run, on I would suspect that it would/could be a good patch albeit in this case temporary.

If you are going to (what looks like) over tighten a threaded tapered fixture into a boss in the case I think you could force the crack to reopen and make an eventual proper fix harder to do. As usual: doing it right the first time usually eliminates the second and potentially more costly second time; ad infinitum (or make it not fixable).

Lee

As usual: my opinion is worth slightly less than you paid for it.

[Piledriver]

I'd take it apart, clean it again and spend the $$$ to have it fixed properly.
The JBWeld will fail in the middle of the desert, or middle of the freeway somewhere.
The bearings etc are all reusable.

Mag expands and contracts too much with heat for it to stay stuck, long.

[Ol'fogasaurus]

"pile, your signature does not cover rotisseries!

Lee

[Piledriver]

"pile, your signature does not cover rotisseries!

Lee

Ah, but a rotisserie is really just an advanced form of jack stand, isn't it?

[Ol'fogasaurus]

Eeeeyewww!

I was trying to be cute but now that you got me thinking about it... maybe in the abstract you could consider it as a fixed jack stand. Maybe this is a "tools" subject as now that I have had mine for 20+years I have a lot of things I would not do again. If I get a chance later on today I will sit down and think about the changes I would/will make on mine.

Lee

[Leatherneck]

Thanks for the input guys, I will see what he says tomorrow and go from there, I'm not interested in filling it, just sealing it which to me should be just run beads overlapping it but I've never done a case before either.

[Piledriver]

Thanks for the input guys, I will see what he says tomorrow and go from there, I'm not interested in filling it, just sealing it which to me should be just run beads overlapping it but I've never done a case before either.

The only way he'll really be able to fix it properly is "v" cut out the crack, and fill it back up with weld.
It will be as strong as the original case, or near enough.

The crack will already have a bunch of unweldable garbage oxide and possibly oils etc in it, welding over the top would be ~like gluing a band aid on an axe wound..

[Leatherneck]

I went and talked to the machinist and was told as you expected that for him to repair it the case would have to be broke down, area filled and then drilled and tapped. I've got to tell you "I gots to know" if the JB Weld will work. So I began by cleaning it up

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Then I started cleaning out the crack and drilling the end of it out.

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Opened up the crack some

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Ready to start adding the JB Weld. I after cleaning I used Toluene and Keytone then blew it out hoping to get anything trapped.

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[Piledriver]

Show the machinist the pictures, he might TIG that up, you have 95% of the work done.

He may want to preheat the case to 250ish F, which may be why he wants the bearings out.

I think that's probably weldable with localized preheat, but I confess I have done no mag welding. Yet.