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Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 12:21 pm
by Steve Jelf
Three of the exhaust manifolds I straightened were so far gone that they didn't survive the process. Would it be worthwhile to vee cracks like this and braze them?
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 1:08 pm
by Russ T Fender
Steve I have plenty of warped maifolds you can have. I used to straighten them but found that I was spending too much time and using more welding gas than it was worth. The repro manifolds are fairly cheap and work great. Other than for the exercise, I would not bother.
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 1:10 pm
by Ruxstel24
I agree with Russ, even straight ones aren't worth much more than $25...
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 1:31 pm
by John kuehn
If it wasnt a fairly rare or one of a kind manifold I think I would forget it. The repos are pretty decent and will last as long as you own a T. This is one repo T part that’s pretty good I think.
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 1:37 pm
by Scottio
I also agree with the others in just replace it however if you are a fix it guy like so many of us are I would use a spray bar to repair cast iron rather than braising it.
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 1:39 pm
by Steve Jelf
I believe the only problem with the reproduction manifolds is that they're all 26-27 style. If you're trying to be "correct" for other years you have to find a good original or fix one that's slightly bent. It's sort of like the 26-27 gas tank problem, but the other way around.
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 2:18 pm
by Mindless Automaton
If i had the resources, i would try to fix it, because i'm strange. That and obvious location problems.
If you do fix it, show us out of curiosity.
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 3:21 pm
by sweet23
Steve, The heat from brazing the crack would likely pull the manifold the wrong direction, and you would be back where you started.Darryl
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 3:44 pm
by Allan
Daryl raises a good point. I think it would only work if you can make whatever weld you decide on with the manifold and glands bolted to a decent jig, to keep everything in line.
Allan from down under.
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 3:58 pm
by Wayne Sheldon
I have seen exhaust manifolds brazed, and work fine. However, generally, model T manifolds can get a bit too hot for brass. A nickel bronze braze might be a bit better. Still, exhaust manifolds are better done either by actual cast iron welding, or the metal spray mentioned by Scottio (at least I think that is what he is referring to?). I have never done that myself, however I watched a demonstration up close of it being done and was quite impressed by it. I had hoped to get the supplies, but couldn't afford to, although the basic kit isn't (wasn't?) very expensive.
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 4:14 pm
by GJScholz
If you really wanted to attempt it, couldn't you stick it onto an old block, and work on it there? It CANT move out of line that way.... ??
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 4:22 pm
by George Mills
Steve,
The replacement manifold 3060B is for everything 13-25 and 26-27 when not vaporizer.
I know, you can fix or repair anything with ingenuity but new ones that fit great, look great, and have really good counterbores are less than 100 bucks delivered.
The price is the same as it was 25 years ago when I bought one when an old timer told me to not heat for nut removal, cut the pipe off, give it to him and he could walk it off with a drift and a hammer in his vice. I got back a bucket that looked like one of those chocolate Easter bunnies that was dropped from about 100 feet! I was disappointed when the old was destroyed, yet really impressed with the new one.
I have bought several since and the threads come in full. Work a nut on and off while on the bench before trying it in a car
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 5:18 pm
by varmint
Steve, it may be worthwhile in other ways than money. Weld or braze, not sure which (I've never personally brazed before). I am curious how far the non-visible crack goes and might even break it the rest of the way before repairing.
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 5:21 pm
by DLodge
Have never done any brazing, but I made some braised short ribs in the Crockpot last week that were really good!
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 5:51 pm
by DanTreace
In the '60's was hard to find a repro manifold.. had one like that cracked, in the same place, and took it to a shop for welding.
Came back with a big cast iron weld all the way around, about 1/2" wide and 1/4" tall. Looked odd, but no leak there. But was out of alignment, so used the flat asbestos gaskets back then, seemed to work out.
Today, I would just order a new one!
Have carried good used, nice threads, with fairly real straight ports, even had a straight edge on the swap meet table to show. Couldn't sell them for my asking, finally after 3-4 swaps, got them gone for $10 each
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 6:37 pm
by Rich Eagle
Pardon my mis-reading of this title; "Wedding advice: Is it worth trying to fix?" I was hoping for help.
My cataract surgery and anesthesia today may be to blame.
Please excuse the interruption.
Rich
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 6:51 pm
by tdumas
Brazing won't work well on a exhaust manifold. An exhaust manifold can get red hot with the spark retarded.
Re: Welding advice: Is it worth trying to fix?
Posted: Wed Jan 09, 2019 11:39 pm
by ShirkWood
I've welded a half inch diameter hole in an exhaust manifold with cast iron rod. The best rod I found is an original Model T piston ring. It is some nice cast iron! The hardest think to find is cast iron flux (the flux I use is red). I had found flux on the Internet but could find anything local. Straighten it when you are done if it needs it. That repaired manifold has been on the car for about five years now.