MTFCA Forum

Whaddya think? Is this manifold a little warped? Easy to straighten, right?

Not so easy. Has to be heated up in the areas of the bend and bent into shape. Many times they will crack in the process.
That manifold looks very thin at the two center ports like someone might have ground the holes at one time.
It is time to spend a few dollars and buy a new manifold. Then whatever type gaskets you use, be sure to place the glands to hold it in place when it gets hot so it won't bend again.
Norm

You could use that manifold to develop a technique (see below) - but as the man said its a but thin around the collar
Some old discussions on how to do it
Method 1
http://mtfctulsa.com/Tech/manifold.htm Method 2
http://dauntlessgeezer.com/DG82.html Method 3
http://www.mtfca.com/discus/messages/331880/342833.html

The manifold came off my friend Gene’s ‘22. We took one look and ordered a replacement. It’s been one thing after another....frustrating! I guess that’s the Model T experience you keep hearing about.

Soot stains make the openings look like the walls are thinner than they are. Unfortunately, the PO used one-piece flat gaskets that don’t have glands with the result that one end of the intake manifold leaks too. We’ll use the good ones when we put the new manifold on.

We’re trying to get it running well enough for a tour the end of next week...wish us luck!

I think they burn up faster when run with leaky gaskets. That can allow some oxygen into the very hot manifold due to exhaust pulses. I used to see exhaust manifolds cracked, warped, and burned out on '70s cars with AIR pumps on them.

I have tried to straighten a couple of them. Not successful yet. One of them suffered from a shifted sand core, was almost 3/8 inch thick on one side, nearly paper thin of the other side. It snapped instantly!
The other one was tough. I actually made a jig and clamp to press it when heated. Never got it hot enough to bend but boy was it HOT!
Some day, I may try it again. But so far, I have always managed to find one that was straight enough.

Cast iron is a lot different than steel. Old cast iron exhaust manifolds often seem more like that stuff they used to make flower pots out of than metal.

The repo manifolds they make today are pretty good. I bought a new one for my 21 Touring and decided not to try to straighten another one. It’s my opinion after I straightened one that the time spent, and gas for heating it didn’t save me all that much money.
I decided to try it and it worked but wouldn’t do it again.

The last one I did was that far out it would never re-shape with heat, so I did a cut'n'shut on it. Cold cast arc, 1/2" at a time with a lot of peening.
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With the increased cost of gas, and unless you are doing them a lot, I think is best to advertise for a nice one or buy a repop. Even guys that do them all the time will burn through one on occasion. Just saw where a small batch of model NRS exhaust manifolds were made for $900 a pop. It’s basically a reverse image T manifold. That should make buying a new T one more palatable , and help us appreciate our suppliers a bit more. They have a huge investment in the effort. JMHO, as always.

And of course, arstralia is a whole ‘nother ball game. Nothing is easy there.

I have seen a couple that were cut between the second and third ports, and welded back together. If you can stand the appearance of the weld, it is not a bad idea. Easy to get two pairs of ports into a straight line. With the two pieces bolted to a block with gland rings to hold the line, it should be OK. One that I saw was welded, the other bronzed.

Allan from down under.

My friend ordered a new manifold from Snyders and got it in two days! We put it on using gaskets that have a steel gland and copper ring. It fit perfectly, went on easily (with two pairs of hands) and appears to seal properly.

While I admire the ingenuity shown by those of you who have successfully straightened a manifold, it's a bit more than we want to tackle. Now, if a new manifold was $900...it might be a different story

My friend added a newly-rebuilt Holley swayback NH and voila! It starts and runs! The engine sounds better and runs stronger. If nothing else shows it's ugly head over the next couple of daysI think he'll be able to join us on a two-day color tour the end of next week.

Thanks for the info and advice.