Kestrel

Fixing a cracked manifold ?

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Here's a sad photo of the back of my newly acquired '51 Buick Super  263's intake manifold. It's seen better days for sure. As a temporary fix, do you guys think JB Weld, if prepared and applied right, would hold me over until I can locate a good used manifold ? I have no idea how hard or long it could take to find one. Any suggestions where to begin a search or where to place a want ad would also be greatly appreciated. The casting number on the manifold is 1338 252 6. I'd really like to do it right the first time around. I live in Ct if that helps anyone that might have one lying around.?

 

At the least I would think both exhaust and intake manifolds should come off and milled true before I go replacing gaskets. Thanks guys !!IMG_0951.thumb.JPG.b5be87ad471b99ac7d2780b01c902c35.JPG

 

 

 

 

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I do not see why JB Weld or epoxy would not work. The area affected holds no coolant.   It  is also not having to hold high pressure.    

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I tried this last year, and it's still holding up at 1500 miles or so, although my repair was on a runner and not the heat box.  You may want to disable the heat riser if you use JB Weld in that location.

 

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Darn. That manifold has a different carb bolt pattern (3), mine is 4. Thanks anyway. Good price for someone else looking.

 

Aaron, I read your old thread. Encouraging to hear an epoxy might tide me over. The engine idles smooth and no change when I sprayed a little carb cleaner into the cracks. Maybe they don't go all the way through. I'll know more when I yank it off. My heat riser throttle is frozen. Probably not uncommon. 

 

Thanks guys.

 

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That's true, that damage is just cosmetic. There's an external "box" around the manifold that is what conducts heat from the exhaust riser, while the "manifold" itself is a separate piece inside and that's where the air/fuel mix flows. Check out the inside of my 1941 manifold, which I cut up to clear the exhaust headers I made. Yours should be similar even though it's for a single carb. Epoxy should hold just fine, maybe even indefinitely if the heat riser is disabled. It will still get pretty hot, so make sure the epoxy is rated to 400-500 degrees, but you should not have issues with it blowing out or leaking.

 

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22 minutes ago, Kestrel said:

Darn. That manifold has a different carb bolt pattern (3), mine is 4. Thanks anyway. Good price for someone else looking.

 

Aaron, I read your old thread. Encouraging to hear an epoxy might tide me over. The engine idles smooth and no change when I sprayed a little carb cleaner into the cracks. Maybe they don't go all the way through. I'll know more when I yank it off. My heat riser throttle is frozen. Probably not uncommon. 

 

Thanks guys.

 

 

It is surface damage for sure.   I would fill the cracks with JB Weld to hold what you got.  Then bide your time looking for a replacement.   Perhaps take the damaged surface material off to a flat surface and JB Weld a flat metal cover over it.    

Edited by avgwarhawk (see edit history)
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That's great to hear. Your photo tells it all.  I always assume the worst with these things. Maybe now I can put some money towards a lift system and get this beast off the ground. ?

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All good advice from posts above. I agree that the heat riser valve was stuck in the “heat” position.  So either try to free it up or remove it completely.    

I had to junk an intake manifold a few years ago because there was a rust through from the outer plenum to the actual intake tubes. 

Joe

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Is brazing a lost art? Cast iron brazes without much problem but must be clean to bare metal. Fit isn't critical as brass will fill large gaps. I was never able to make a brass bead pretty like a weld but it is easily ground to a decent looking job. There are high temperature epoxies but I don't think JB Weld is one of them. Bob H

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That intake is know to crack and fail.  Memorize the part number that is cast into the intake to help you find a replacement.  What Joseph Indusi said is true. those intakes will burn through from the bottom where it bolts to the heat riser.

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Thanks for the brazing idea. I'll be removing  it soon and will try to find someone with that experience. I like the idea of disabling the riser indefinitely. How important is this component anyway if the car is driven in mostly warm weather ? My '32 Chevy gives the driver complete control in the form of a manually operated pull knob on the dash. I never fool with it and leave it in the closed position. I've been warned carburetor icing can occur in low 50's F and high humidity. More of an issue in airplanes I imagine. No expert though. 🙄

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From J-B Weld Tech Pages, note however there are three other J-B Weld compound formulations sold, neither of which they recommend for heat conditions / exchangers, this one below however does by no doubt by a lot.  The overall cured density of the J-B compound may apparently be linear in relationship to it's heat capacity so increases as their formulations for heat resistance increases: 

 

J-B Weld™ ExtremeHeat™ is formulated to allow for repairs to iron, steel and metal in high temperature environments (2400°F / 1300°C). When fully cured, this metallic compound can be drilled, machined or sanded. It is great for repairing cracks, small gaps, seam connections or holes in exhaust manifolds, pipe connections, mufflers, catalytic converters, outdoor grills, fire boxes, gas and commercial furnaces and water heaters. This product is water based, non-flammable and contains no solvents or Volatile Organic Compounds (VOCs).

 

 

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I  found it at the local NAPA store. Thanks ! I never knew JB Weld made such a thing. I've always used their traditional 2 part product. I'll give the ExtremeHeat a shot.

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