Warped exhaust manifold.

[Petrah Phyre]

Did not know they could be this bad. Should have measured it before I tried to install it. Would have saved on the frustration. My only spare doesn't have any threads left. I have seen where some have teased them back with heat, but I am not sure I'm up for the challenge.

[babychadwick]

You "might" have luck with rings, heating and bending will most likely result in cracking it. The best solution is to buy a new one
https://www.modeltford.com/item/3060B.aspx
There was a time when new ones weren't available and I can remember my grandfather doing what he could to try to straighten them, I don't know how many would crack and break before he would be lucky enough to get one to work. He had even made up a jig for the job.

[John Codman]

My '27 was much worse then that. A new manifold from Lang's solved the problem.

[speedytinc]

Seen worse, up to 5/8" on that rear port. Yours looks about 1/4". Thats straightenable with a reasonable success rate.
The tooling or fixturing, prep, plus gas are not worth it for a one time need. A new one is the smarter play. If the threads are good, ists worth $5-10 to a guy that straightens them @ a swapmeet.

[Norman Kling]

I would recommend a new one if you can find one. If not, there might be someone in your area experienced in bending them. Final resort would be to put glands in the first and fourth ports and use the flat gaskets. Then keep your eyes open and if you find a straight one at a swap meet buy it or best try the vendors and purchase a new one when available.
Norm

[Steve Jelf]

A manifold warped ¼" or more is likely to crack, though I've been told that can be avoided by partial straightening, letting it sit a day, then final straightening. I haven't tried that yet. In my experience most manifolds warped less than a quarter inch have survived straightening.

A new manifold costs $84 plus shipping. I spent about $45 making a straightening jig. Do I use up $39 worth of gas per straightening? No, not even close to that. But did I use up $39 worth of my time making the jig? Yep.

https://dauntlessgeezer.com/DG82.html

[Petrah Phyre]

Almost clicked 'order' and then though, what would it hurt to try. I know not everyone has a piece of 1" plate lying around, but that, two c-clamps and a turbo weed burner took me in the right direction. I kept it good and hot and slowly turned the clamp at the center. I did back it off a time or two to make sure I was not just pushing a hole through the top. All looks like it came into alignment. I am now "cooling" it in front of a space heater. It is a tad chilly here, so wanted to slow the process. I dont have a bucket of dry sand or I would have went that route. Now to just pray that things stay put and I will have saved a few pennies.

[Oldav8tor]

When you put your straightened or replacement manifold back on be sure to use the proper gaskets like these <https://www.modeltford.com/item/3063-64.aspx>

[speedytinc]

Good on you. I also do some of my best work when I have nothing to loose. I am a bit surprised your simple jig does the job. Every bit as good as my purpose built manifold jig.

[John kuehn]

The jig your showing works great! The one I used was one I copied from one of the T club sites and took a a little more to build than yours.
Looks like using a good straight piece of flat stock or maybe a length of angle iron works well with the C clamps. Just using something from the scrap pile and some c clamps does the trick!
Does your turbo weed burner use propane or?

[Petrah Phyre]

Tim, those are the gaskets I have on hand.

John, propane.

It is cool now and does still have a slight deflection. No twisting though. We will see if it is close enough that it wants to sit where it is supposed to.

[Petrah Phyre]

Succes. Mounted up nicely. I know, I know. The parts aren't correct, but for now, they hold things together. This is a patch, get it running for a quick jaunt. Full rebuilt will take place in the future.

[Joe Bell]

I have straightened many of them, I use a breaker bar and socket, heat the manifold and let the weight of the wrench move it, it you force it they will break, if bent really bad like 3/8 of inch I would heat it a couple different times, do not try it all in one heat or they will break, if you let them cool down over night I have had better luck at it. Just my two cents on it!

[Les Schubert]

Joe
How hot do you heat them? RED?
I probably have 4 or 5 to do

[Steve Jelf]

Beyond red. Orange to yellow, wherever the wrench starts to fall.

[Allan]

I don't consider those gaskets "proper". The bent sheetmetal rings are not round, they easily deform with heat and get dislodged, and they do not hold the manifold in place "Properly". Much of this can be overcome by cutting your own gland rings from suitable exhaust pipe, this giving you a thicker gland with no joint to allow deforming. Use the copper gaskets if you like for the seal.

I prefer the more expensive, thick, one piece, flanged, copper gaskets. These are re-useable over and over. They are thick enough that you can file a slight taper either side to aid in getting the ports aligned. The extra cost is peanuts compared with the time and effort expended in trying to get a warped manifold to fit and is good insurance to hold any new manifold in place to stop it warping.

Allan from down under.

[Joe Bell]

Les as Steve said as hot as it takes for the wrench to fall on it's own, be careful when they are that hot it is not much more then they become two pieces.

[Mark Nunn]

Where do you put the breaker bar, socket and wrench? Does anyone have a photo?

[jab35]

Mark: The 'falling wrench' method and associated fixture are shown here: http://mtfctulsa.com/Tech/manifold.htm

Petrah Phyre: Thanks for sharing your uncomplicated approach to straighten the manifold. jb

[Scott_Conger]

Caveat: I have never straightened a manifold. Not with heat, not with any method.

The point I have always pondered is that every warped manifold I've come across, it is the rearmost and ONLY the rearmost exhaust port which is out of line. If this is the case, then why is it that every picture I've ever seen of straightening the manifold concentrates heat to a very small portion of the manifold where the manifold is NOT bent. Yes, it works, but concentrating the entire straightening stress on a very small area seems like it is the culprit in cracking that often occurs. Would it not make more sense to heat the ACTUAL area that is bent, and spread the stress across a much larger area? You lose a little bit of leverage at the wrench, but you'd be straightening what was actually bent, and as mentioned above, would be spreading the movement/stress across a larger area. It might take more gas to heat a larger area, but I'd bet that the risk of cracking would drop off considerably.

[jab35]

Scott: I agree. It takes a much larger flame to heat the larger area but as Petrah clearly demonstrated it works. The quick heat it white hot in a dine size spot, not so good.

[tdump]

If parts are easy to find,a new 1 is nice to have.
BUT if you do try the heat and dropping wrench method,do it exactly as explained and it does work. I made the mistake of touching the wrench on the last 1 I tried and it broke.
just a light touch,wasted the time.
So do it exactly as explained.

[Petrah Phyre]

I did heat the entire manifold with my torch. Used to braze, cracked cast tractor manifolds back in farm power mechanics in high school. We would always throw them in the forge until good and hot before, and for a short time after. We then would bury them in dry sand to slow cool. Usually worked out fairly well. The farmers we were working for were a little tight on buying new parts. Most things had to be fabricated.

Eventually my manifold will be replaced with a header and this one will be saved for my wife's '25 frankenT she wants me to build. She wants a C cab PU on a car chassis...ok, what ever you want Dear.

[J1MGOLDEN]

That heat and repair plan does not work very often for a few reasons.

Once they are back in alignment, the space between the #2and #3 exhaust port has lengthened about 1/8th inch and the ports still don't fit.

The exhaust manifold cracks almost in two between the #2and #3 exhaust port the first time the engine overheats.

The crack is welded and soon cracks again.

[Allan]

My experience, and method, is a little different. The back port does appear to be the most out of line, probably due to it being super heated by the three in front as the gasses are expelled. However, careful attention will almost certainly reveal that there is a bend throughout the manifold, not just between the last two ports.

When checking, I place my straight edge focusing on the two centre ports. Almost invariably the front port will be dropped a bit, and the back one more so. Unless the bend in either port is greater than 3/16", the manifold can still be fitted, as is, and with gland rings to stop it bending further.

I make offset gland rings using exhaust pipe so there are no gaps like the rolled rings suppliers sell. The two centre ones are the standard length. I cut 4 extras for the front and rear ports. From the straight edge reading of the manifold bend, a pair of rings is set up with an offset to mimic the amount of bend indicated. These two are welded together on the inside, making a solid gland ring. The same process for the second out-of-line port.

The bent manifold will be slightly shorter than optimal due to the bend. This too, as well as the bend, can be compensated for by slightly rotating the offset glands when fitting the manifold. I fit the glands into the manifold and check the fit to the block, rotating the offset glands as is indicated. The whole can then be fitted with the copper rings as is the usual practice. I always use a heat proof manifold sealant, to help hold things in place, and to provide a sound seal at each port.

I did this initially because new manifold were not available. I still do it to save original manifolds which have good threads, to save the not inconsiderable cost of a new manifold and the shipping costs and the delays, and to have a correct looking manifold on an earlier car.

Allan from down under.

[Les Schubert]

Allan
That is a really interesting concept. I will try it!
Thank you for sharing.

[Susanne]

I had a bunch of warped manifolds, so I started playing with them and a rosebud torch...
The first one I tried to straighten in one fell swoop... fell it did, as it broke. Darn.
Checked the next one - no cracks... Heated it slower, again, tried to straighten in one shot - pulled a crack. Darn again.
Then I tried something different - because the warp develops over decades of use with a uniformly hot manifold, and pulled down by the pressure of the exhaust pipe, I figured what if I tried kind of the same technique to un-warp them?

First I heated the entire manifold and let it cool slowly... thermal cycling and annealing the manifold under no pressure whatsoever (kind of like making a knife). I figured if there were any stress spots in the casting, this would help releive them.

Couple days later, I again heated it slowly to a uniform temp (hot but not glowing) in my gas forge. Once evenly hot, I used the rosebud to increase the heat to the area I wanted to straighten (ID'd by soapstone marks), and applied fairly light pressure to see if I could get it to start pulling the warp out on its own, BUT - I limited the downward motion to maybe a few millimeters total. Once it had moved, I pulled it, and repeated the thermal cycling. Let it cool, then repeated the procedure.

It took a lot of in and out (and fuel gas), and a lot of time, but all in all, the manifold was eventually straightened, no cracks, no pings. I did a second one (a later one with both longitudinal and radial warpage), probably took a month of effort to get it worked out, but again, it ended up straight, flush, and aligned to the holes in my test block...

My thought was these aren't made warped, but develop the warp over decades of a similar thermal cycling, developing hots spots, and having the exhaust system pull them down... so repeating the same thermal cycle and hot spot with pressure in the correct direction (and pins to brace it where it needed not to be "fixed") seemed to reverse the damage of time, loose or ineffective clamps, and exhaust pipes. Of course, buying new repops is both cheaper and faster, byt YMMV... if nothing else, it was a fun experiment.

[MichaelPawelek]

We just need to start a manifold trading set up with our buddies south of the equator since their exhaust manifolds warp upwards……

[Allan]

Michael, that would only work for those who are prepared to ship overseas. Too many US T owners have an aversion to this for some reason.

Allan from down under.

[CamMan]

I'm surprised no one has mentioned this link - http://mtfctulsa.com/Tech/manifold.htm. I captured these stills during filming of an MTFCA video on this topic. I don't know where this fixture is now that Fred Houston is gone.

[Steve Jelf]

That link is on the page I posted above.

[TRDxB2]

I'm surprised no one has mentioned this link - http://mtfctulsa.com/Tech/manifold.htm. I captured these stills during filming of an MTFCA video on this topic. I don't know where this fixture is now that Fred Houston is gone.

Easy to miss on long threads........ But never hurt's to add it again on them
It was mentioned up above and Steve added a link of him making a similar jig - and in it there is a link to the link you mentioned as well at the end of it he has a link to TULSA manifold jig
Steve Jeff making a jig https://mtfca.com/phpBB3/posting.php?mo ... 3#pr214128
--
Jim Bartsch https://mtfca.com/phpBB3/posting.php?mo ... 3#pr214653

[2nighthawks]

Unless I missed it, I don't see where anybody suggested another alternative,....a one-piece combination intake/exhaust manifold such as the Anderson (ANCO) or Wilmo aftermarket manifold. This was discussed at length on the forum several years ago, and the general consensus was that they just simply don't warp. Besides the fact that they are a larger/heavier casting, you might say that the combination cool intake and hot exhaust through a larger one-piece casting just seems to prevent warping I believe the original purpose of these aftermarket manifolds was an attempt to deal with the poor quality gasoline (back in the day) but an added secondary advantage is that they just simply do not warp. Several other companies also made them besides ANCO and Wilmo. They can still be found at swap meets and probably online. For what it's worth,....harold

[TXGOAT2]

Allan, here in NewAmerica, with an election coming up next November, we'll all soon have our free electric flying cars. When I get mine, I'll gather up a bunch of new manifolds and fly them right to your front door! On the way back, I'll fly over the North Pole and drop cases of Coca Cola for the Polar Bears... diet, of course, since we all know that sugar is carbon ...THE ULTIMATE EVIL!!! I should be able to make the trip with absolutely zero tailpipe emissions and about 18 cents worth of clean, renewable electricity!

[TXGOAT2]

It would be nice if someone could manfacture new, high compression, Ford script cast iron heads and new hot- spot manifold sets with a manual heat valve control. Cost is an object.

[TRDxB2]

Unless I missed it, I don't see where anybody suggested another alternative,....a one-piece combination intake/exhaust manifold such as the Anderson (ANCO) or Wilmo aftermarket manifold. This was discussed at length on the forum several years ago, and the general consensus was that they just simply don't warp. Besides the fact that they are a larger/heavier casting, you might say that the combination cool intake and hot exhaust through a larger one-piece casting just seems to prevent warping I believe the original purpose of these aftermarket manifolds was an attempt to deal with the poor quality gasoline (back in the day) but an added secondary advantage is that they just simply do not warp. Several other companies also made them besides ANCO and Wilmo. They can still be found at swap meets and probably online. For what it's worth,....harold

You beat me to it.... AND they look cool with fins

[2nighthawks]

Frank - Actually, you brought up something additional that I missed Frank. I mentioned the aftermarket COMBINATION intake/exhaust manifold, and the manifold you have pictured is actually an exhaust manifold that is much heavier and larger than the stock Model T exhaust manifold as it incorporates a large mass of additional iron in the shape of fins. It is actually designed to be covered with a metal shroud that forces the airflow from the radiator cooling fan to be heated as the air passes the fins and is directed into the interior of the car for cold weather comfort. I believe that this additional mass of iron also serves to prevent manifold warping as does the COMBINATION intake/exhaust type manifold that I mentioned. In other words, I believe that the combination intake/exhaust manifold that I mentioned, "AND" the aftermarket HEATER MANIFOLD (that I missed) and that you have pictured FRANK, will both serve to prevent warpage due to the larger iron mass involved over and above the stock factory type exhaust manifold. Also, to say it in another way, the manifold Frank pictured, besides being called a "heater type manifold",....I think it could actually be referred to as an "air-cooled exhaust manifold", and this type also, does not warp as does the stock factory manifold. Thank you Frank. OK,...enough,....too many words (as usual for me),....sorry,....harold

[Allan]

I'd rather the not quite correct looking reproduction manifolds presently available to that humungously heavy looking thing with all the fins.

The key to the whole deal is the manifold should be fitted with solid, continuous gland rings cut from exhaust tubing, not those flimsy little bits of bent, unjoined sheetmetal that the vendors offer. They do not act to stop the manifold moving with the heat cycles. At best all they do is hold the copper rings in place when fitting the manifold. The gland ring should be sturdy enough to act as a locator for the manifold, like a hollow dowel pin.

Allan from down under.

[ModelT46]

I had a few old stock (from the 1950s) glands and rings made or sold by AC. The were great and the manifold I am using is an repro sold by Langs in about 1985.

[Stevew]

I was told there were plans for building an exhaust manifold straightening jig in a back issue of the club magazine. Does anyone know what issue these plans were in ?

Thanks
Regards
Stevew

[John kuehn]

My two cents.
The reproduction exhaust manifolds are pretty good. I’ve straightened two originals for my cars and decided to buy a new one for the third.

Is it cost effective to straighten an original? If an original still has good threads and decent shape it can be done but time spent building a jig, Oxy and acetelyene it’s not worth it other than satisfaction that you did it.

[Craig Leach]

Hi Steve,
See the Tulsa club website they have a lot of pics & info on there. mtfctulsa.com/Tech/manifold.htm
I have had some success with straightening manifolds. One issue is cracking when they cool. I bury them in sand or Kitty litter and let them cool
slowly over 8 hours. The manifold on the fire truck was straightened 13 years ago seems to do fine. As others have said the replacement manifolds
are not that expensive.
Craig.

[TXGOAT2]

Pre-heating the manifold in a good-sized campfire with a lot of coals would be helpful. Build the fire over the manifold and let it burn down to coals. Prop the manifold off the ground with bricks. When everything's good and hot, use a weed burner or rosebud torch to do the straightening, then set the manifold back in the coals on the bricks and heap kitty litter or very dry sand over the coals and leave it to cool.

[jiminbartow]

The welding foreman in the railcar repair shop where I worked as VP for 37 years used to bury cast iron parts in oil impregnated sand to cool. I don’t know if it is standard practice but that is what he did when he repaired a broken cast iron bed plate for an Edison phonograph I had. He had been welding since 1960 so he knew all the tricks. Jim Patrick

[J1MGOLDEN]

About 30 years ago, Bob Thompson, the guy from Michigan that brought back the Anderson Timer made a device to put the manifold in an oven with heat up to around 800 degrees.

Then, the screw system on each end with care not to get burned fingers moved the holes back in alignment.

He was only charging about $50 for straightening, but soon realized the electricity to heat the oven cost him more than that, or so he told me.

Then, there were shipping costs each way and it was almost as cheap to buy a new one that seemed to be a good reproduction.

Seems like they were made in Brazil then.

[Rod]

I had two exhaust manifolds that were straightened today by Kenny Edmondson. Here are the pictures.

[MarkS]

My manifold was warped, with the two center ports about 1/8" out of alignment. Since I didn't have enough experience to know better, I built an alignment fixture and gave heat straightening a try, using the "just let the weight of the wrench apply the pressure" technique. The first time I tried it, once the manifold was straight, I stopped heating it and immediately backed off of the push screw. As the manifold cooled, it tended to "spring back" a bit. I tried it a second time, this time when it was straight I stopped heating it and just removed the wrench, leaving the push screw alone and letting the manifold cool on the fixture. Success! Been working fine for the past 3 years.