Exhaust Manifold Sag

Roadster Rich

Roadster Rich

Senior Member
I know I have read about this before, but for the first time face the situation on the engine I am working on. Here is a picture of the manifold I have taken off the car.

Manifold Post.jpg

There is between 1/8 and 3/16 inch with this straight edge lined up with the outer two exhaust holes.

Do I need to replace with this condition?
 
Lining up the old manifold complete with Intake and Gasket is a long shot. To me not worth it. I would spent the $100 and put aa new one on. ken
 
A fellow I knew made a jig to hold the manifold and it had a screw device to put reverse pressure on the sag while heating the manifold and successfully straightened the ports. I wish I had found it at his estate sale.
 
Unless your going for show the new manifolds are great. Add an Aries muffler and you will have a correct sounding engine without an exhaust leak
 
Small wonder that manifolds SAG! Just think of a RED HOT GLOWING MANIFOLD, with 7/8's of the weight of the ENTIRE exhaust system tugging down on it!
I've "thought" of a flat iron strap, from a clamp bolt & up to a manifold stud, for "support"----------
Bill W.
 
I wouldn't bother with the alignment rings that the venders sell they will shrink and end up in the muffler, I heard it said here while ago.
 
Listen to RonC, post # 5 - He knows what I am talking about. That is he knows what he is talking about. That is he knows what most of us know. I would not bother buying the more expensive Porcelain manifold . . . . unless you plan on having the car for more than a decade. The same with the Aries (from Ford Blue Prints) - don't bother with the extra expense of the Stainless Steel muffler . .. . unless you plan on having the car for more than a decade. And if you do put on a new Aries (of whatever material) be sure to paint it with an extreme-heat paint.

I like the engineering idea behind the Gland Rings. I have used them for 50 years, and have never had them 'disappear'.
 
Thanks for the advice. I guess it is another expenditure that should happen. What are your thoughts about whether I need to pay for the new intake manifold to make sure all lines up correctly? I see a note at Bert's about getting the matching intake manifold also to assure alignment.
 
It is possable that your manifolds have been milled, so the thickness of your intake manifold versus the new exhaust manifold would be the determining factor of buying a new intake.

John
 
That's why I used an Otwell heater on one of my As-all the original "regular" manifolds I had on hand had sagged-but the two heater manifolds I had were straight as an arrow-that extra cast iron had kept them from sagging.
 
I always get a new intake for previous milling reasons as aermotor stated... Half dozen one the other... With a new intake just plop it on without resurfacing...
 
Thanks to all. Looks like I will order both the intake and exhaust. More money than I intended to spend, but it always seems it is, and for most of us, we never regret the amount we spend on these cars of ours.
 
I believe that the heater manifolds don't warp due to the greater mass of metal in the area where the warping/sagging takes place. Furthermore, with all that metal on top, it acts as a cooling fin which prevents the distortion. I know, I had a stock manifold that I'm pretty sure was warped. I couldn't keep a gasket on the engine, it would always blow out on the top. Since I put the Autolite heater manifold on, i have not lost a gasket.
Terry
 
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