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Discussion Topic:
Crack in intake manifold
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budlite28 |
12-14-2020 @ 12:54 PM
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Member
Posts: 38
Joined: Oct 2020
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I have a '39 Ford deluxe coupe that I am rebuilding the carb for. When I removed the carb, I found 3 gaskets between the base and the manifold. Further inspection I found a crack in the manifold ( explains the 3 gaskets). There is a bit of a ridge at the crack. Will it present a problem or should I just replace the manifold?
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supereal |
12-14-2020 @ 1:38 PM
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Senior
Posts: 6819
Joined: Oct 2009
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Sometimes the carb/manifold gaskets were doubled or tripled to reduce heat buildup in the carb caused by the exhaust passages in the manifold. Location of the cracks are not visible in the photo. If they don't affect the operation of the engine. If they do, replacement is an option. Manifolds are hard to come by today. I bought one years ago to get the carb on it at a swap meet, and still have it if you need one. And yes, they are aluminum. We weld aluminum at our shop, but you must be certain it is a surface crack. If it extends into the intake ports, it is junk.
This message was edited by supereal on 12-15-20 @ 10:17 AM
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sarahcecelia |
12-14-2020 @ 1:54 PM
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Senior
Posts: 1193
Joined: Mar 2013
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The real deal would be a good used manifold. They are some - what available. You could have it welded, or braised; but ask the welder if it will warp the manifold! (Doubtfull that it would) Is the surface where the crack is, still flat after being welded or braised?? Probably not; becuase the weld or braise will stick up a little. Braise is brass, and can be CAREFULLY FILED FLAT; WELD NEEDS THE M/C SHOP TO RE-SURFACE THAT AREA!!!! If you're not sure; after welding/ braising; take it to a machine shop to have them check it; and if it needs to be re-surfaced, the machine shop can do it.
Regards, Steve Lee
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budlite28 |
12-14-2020 @ 1:59 PM
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the crack is shown in red. Is it possible to have it welded & machined ?
This message was edited by budlite28 on 12-14-20 @ 2:00 PM
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Jacques1960 |
12-14-2020 @ 3:14 PM
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I’d suggest welding and decking the mating surface of the manifold. If heat is an issue for your carb set up, toss in a spacer.
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jims33 |
12-14-2020 @ 3:32 PM
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Posts: 25
Joined: Dec 2011
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Is that an aluminum manifold? If it is, brazing is not possible. Aluminum can be welded and then machined flat - that would be a good repair. If it's cast iron, welding is not likely to work out but brazing would be ok. It needs to end up perfectly flat so that it doesn't draw air in.
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budlite28 |
12-14-2020 @ 3:54 PM
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Posts: 38
Joined: Oct 2020
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yes it is aluminum. I'm checking around town to see if there's a shop that can weld, thanks for all your help
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TomO |
12-14-2020 @ 3:56 PM
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How much of a ridge is at the crack? If it is 1/32" or more, I would remove the studs and stone it flat. If you are concerned about the crack growing, you could drill an 1/8" hole at each end and fill wit JB Weld for aluminum. The crack does not appear to be in a place to cause a vacuum leak, so if it is less than 1/32", I would just use a good, new gasket. The thick carburetor gasket should allow the carb to sit flat.
Tom
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woodiewagon46 |
12-14-2020 @ 4:01 PM
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Senior
Posts: 704
Joined: Nov 2012
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This is the way I would repair your manifold. I would first remove the studs. I would then cut a deep "V" groove from about 1/8" from each stud hole where the crack is and then TIG it up. Then, dress it flat and you should be good to go. The only issue you might run into is contamination of the aluminum. Aluminum is very porous and it must be absolutely clean to TIG weld.
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51woodie |
12-14-2020 @ 5:44 PM
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Posts: 516
Joined: Jan 2017
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It looks to me as if there is/are gasket/s in place. I could be wrong. What does the bare face of the carb flange look like?
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