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Post by 90GTVert on Jun 15, 2019 11:34:57 GMT -5
I chewed out as little as I could, roughed it up, cleaned with acetone, heated a little, refilled, and then heated a little. Fingers crossed.   |
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Post by benji on Jun 15, 2019 11:43:32 GMT -5
Maybe take some spare aluminum and grind it into dust and mix it into the jb weld?
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Post by 90GTVert on Jun 16, 2019 16:24:01 GMT -5
I cut out an area for the bolt and reinstalled it.  Pressure tested again. More leaks. Now leaking in other areas, on the edges.  Ground out more JB Weld and tried again. This time I hooked up a vacuum pump since I already had the engine ready for it because of the pressure tests. Heated the JB a little. Maybe it helped to pull some wherever it is needed?  |
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Post by 90GTVert on Jun 18, 2019 8:06:53 GMT -5
I pressure tested it again after the last repair and had only a small leak by the bottom right corner of the filled area. Upon closer inspection, the filler wasn't leaking. The case has a crack in that area and bubbles while pressure testing were also coming from the front of the case, but I couldn't see anything.    I ground the area down a little to see if that told me anymore about the crack. It extends toward the cylinder quite a bit.  Years ago I was going to install a fitting into my car's transmission pan and I bought a product called Muggy Weld that is supposed to bond various unlike metals. I changed plans and never used it on the car, but I still have the rods and flux. I thought maybe it was worth a shot to see if I could fill the crack in the case.   All I've got is a propane torch, so I wasn't sure if that would even work. I couldn't seem to get the case hot enough to melt the solder without keeping the torch there. Here's the first piled up repair that fell right off when I tried to grind it down.   I tried again, keeping the torch on for longer. I could get it to melt the solder by dabbing it on the cases as long as the torch was still aimed at or near it, but again I couldn't take the torch away and have the heat from the case melt it. I do have a MAPP gas canister here, so maybe I should have tried that. The repair looked better, but then it chipped off too when I messed with it.  Then I realized that it looked like the crack went all the way to the edge of the cylinder base, or really the base gasket. I can see that in earlier photos here, but it's hard to see in person. I put a little pressure in the cases again and sprayed on some soapy water and saw that it is indeed cracked and leaking at least to the edge of the base.  I had sprayed the base before all of this started and saw no leak/bubbles, so maybe I've made it worse by messing with it. Regardless, it's looking like this is going to become a pain with a lot more disassembly and reassembly. Possibly going through replacing this case half and re-modding it.  |
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Post by aeroxbud on Jun 18, 2019 12:17:32 GMT -5
This is starting to go down hill very fast. Looks like it could be a right pain to fix properly.
Like you said, perhaps just get a new case half.
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Post by 90GTVert on Jun 18, 2019 16:18:43 GMT -5
This is starting to go down hill very fast. Looks like it could be a right pain to fix properly. Like you said, perhaps just get a new case half. I'm not against fixing it. Getting a new case half is actually a big deal. Has to be cut for the crank, cut for the cylinder, filled, port matched and trenched. The joys of engines more than double the stock displacement. It takes quite a bit of time. I put more effort into filling and working this set than I ever have before, so of course this would be one to crack. |
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Post by 190mech on Jun 18, 2019 17:23:10 GMT -5
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mattyslimz
Scoot Enthusiast
Posts: 222
Location: Northern Virginia
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Post by mattyslimz on Jun 18, 2019 17:40:05 GMT -5
Once you pull the cylinder, it may not be as bad as it seems. Fingers crossed.
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Post by 90GTVert on Jun 19, 2019 7:44:58 GMT -5
I took the cylinder off and it looks like the crack stops as it hits the edge of the base area. In the pic, it looks like there's another crack in the base area, but it just looks like a scratch to me in person and I don't see anything continuing from that area in toward the crank down the wall of the transfer port. I may take more pics to look at before I decide on anything though, because having a 4K pic shows much more than I see IRL.  Ryan is sending me an oxy/propane torch in case I want to try the solder again. I didn't even ask. Just got a PM that he was sending it. Thanks! I'm not sure if it'll work out, but if the other option is replacement then there's not a whole lot to lose. If the heat remains local enough, it may be OK. Not sure that the JB will like it getting much hotter. I caught the very outside of it on fire with just the propane torch when I guess I was aimed at it more than I should have been. I got the back plate on and redid the wiring for the new blinkers. There are runs in the paint, but it'll do for now.   |
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Post by 90GTVert on Jun 19, 2019 21:00:49 GMT -5
Sounds like the Muggy Weld that I have, Super Alloy 1, is not the right stuff for this. I looked it up and found instructions from the company online. Here are excerpts... "Super Alloy 1 is not suitable for diamond plate aluminum or cast aluminum. Please use Super Alloy 5 and an oxyacetylene torch for these applications. " "If the Alloy 1 is not flowing or bonding to the pot metal, it may not be pot metal. Pot metal and cast aluminum are mistaken for each other quite frequently. Make sure your project is not cast aluminum as the Super Alloy 1 does not work on cast aluminum. Super Alloy 5 works fantastic on cast aluminum with an oxyacetylene or mapp-oxygen torch. " Based on their descriptions, it also sounds like I had the cases plenty hot for the application of alloy 1. They say if the flux turns light brown, it's hot enough. Super Alloy 5 starts at $59.00 for a small kit and it says it melts at 600F. 600F sounds way hot for this. Can't imagine that doesn't melt or set fire to the JB Weld and I'll prob melt cases and maybe warp stuff I'd think. The "Aladdin" rods that the welder down the road used on the head melt around 450F according to him. I think I need to look into other options. It's probably all a terrible idea. EDIT : The link below with info about rods says that Aladdin rods and those like it melt around 730F. Specs from Aladdin seem to back that up. www.weldingtipsandtricks.com/aluminum-brazing-rods.html |
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Post by oldgeek on Jun 19, 2019 21:18:17 GMT -5
IMO you are not going to achieve satisfactory results with anything using a flame to weld or solder the cast aluminium. I think the only thing that will do it is a skilled TIG operator and a good tig machine. I have some solder that supposedly works with aluminium, but I have never been successful trying to use it. I will send it to you if you want it, I sure dont need it Lol! www.harrisproductsgroup.com/en/Products/Alloys/Brazing/Aluminum/ALCoR.aspx |
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Post by repherence2 on Jun 19, 2019 21:30:40 GMT -5
what about sealing it internally with POR-15 gas tank sealer? pressure comes from the inside of the case, so if the sealant is on the inside of the case, as pressure builds, the seal should get better. I'm pretty sure it won't blow out. trying to seal a pressure boundary externally can be troublesome.
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Post by ryan_ott on Jun 19, 2019 21:35:57 GMT -5
I’m thinking a filler material is only needed to fill a gap, it’s a hairline crack that with the correct temperature you should be able to fuse it back together. I’ve repaired a broken water pump ear with the same torch setup, no filler just molten aluminum.
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Post by repherence2 on Jun 19, 2019 21:47:13 GMT -5
well, I just googled "brazing aluminum" and YouTube showed a video by MuggyWeld.com Super Alloy 5. impressive! I say super alloy 5 all the way.
*edit* Blue Demon Triple Play aluminum-zinc rods look pretty impressive too.
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Post by 190mech on Jun 20, 2019 0:02:29 GMT -5
If you are gonna hold a torch to that case,I'd have it disassembled and super cleaned with acetone before attempting it..That premix has surely crawled into any cracks so it'll just bubble out with heat keeping anything from sticking..A poor mans 'dye check' is baby powder as the premix will wet it revealing just how far that crack(s) really goes..bet its longer than what you are seeing..A true dye check test would be best,the crank case is one of the most highly stressed parts on a 2 stroke engine,I'd put that piece on the shelf with the fried pistons for the crowds to look at when the 2 stroke scooter museum is opened!  |
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