exhaust manifold leak

[rusted]

My exhaust manifold is leaking around #1 and #4. I hade the manifolds resurfaced but cannot get it to seal. I am using the one piece gasket snugged down to 45 pounds. Is there a better gasket I should be using? Thanks for any help.

[Marshall V. Daut]

1. Make sure the ports are even across the tops. #4 usually droops.
2. If the ports are in alignment, insert gland rings into the exhaust ports.
3. Use one of the two expensive copper gaskets with the gland rings.
4. Ensure you are using the special thick circular washers with the manifold nuts, NOT a stack of flat washers.
5. Tighten the nuts evenly and after each heating for the first few times the engine runs.

Marshall

[BILL WILLIAMSON]

On BOTH sides of the copper gasket, I use a TINY bead of High Temp Exhaust Sealant, around the gasket bores & re -torque several times. NO MORE pesky leaks.
Bill W.

[RandyinUtah]

I feel that the correct torque is around 25 foot pounds no the 45 as stated.

[Brian T]

If you have had the 2 manifolds resurfaced be sure the gland rings are not holding the manifold away from the block, that is assuming your are using them, best to leave them out.

[rusted]

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I just checked the Les Andrews book and the torque is 45 ft. lbs. I am not using the rings because I don't know how much was taken off to true the manifolds and I didn't want them to be to thick and hold the manifolds out. I think I will try Bill's trick and see how that works. Thanks to all for the info, I will work on it

[Jon]

Google Remflex. If you have a driver and not a show car this is the best I could find.

[Mitch//pa]

Buy both new manifolds.. (It's not an arm and a leg) //old manifolds are distorted and they usually leak again soon..
You do not need to surface the new ones
Use copper gaskets, with new studs, nuts and concave washers... (Remember dome out)
Sealer not needed on anything
It will look slick when done ( I like the porcelain coated one)

[Marshall V. Daut]

Look inside the exhaust manifold ports. If you can still see recesses for the gland rings, you are o.k. to use them. Consider that these narrow rings fit inside the manifold, pass through the thick gasket and then nestle inside the engine block recesses, which should still be there. If the manifolds were trued to such an extent that the exhaust port recesses are gone or barely visible, then gland rings will not work. Otherwise, try them. You will be able to tell while tightening the nuts whether the gland rings are binding.
But before you do anything, check for straightness across the tops of the exhaust manifold ports. If #4 is drooping, you're just wasting your time with ad hoc "fixes". No amount of bulletproof gasketing, sealants or torqueing the nuts will help. The extreme pressure of the exhaust will eventually blow out the overhanging gasket on #4. Trying to straighten the manifold in an oven usually results in it returning to its warped state because of its "memory". Now that you had both manifolds planed, if you order a new exhaust manifold as Mitch recommends, you will also need to order a new intake manifold, unless you have one lying around that has never been trued. Your intake is now too shallow to mate with a new, thicker exhaust manifold, which will result in a gap between the intake manifold ears and the engine block.
Marshall

[larrys40]

Originally Posted by rusted

My exhaust manifold is leaking around #1 and #4. I hade the manifolds resurfaced but cannot get it to seal. I am using the one piece gasket snugged down to 45 pounds. Is there a better gasket I should be using? Thanks for any help.

We all have our favors of check and remedy. I do surfacing of manifolds and have done and mounted many. I usually check the lower end of the manifold alignment using a long straight edge. if the ports don't line up reasonably close then it will most likely leak. I'm not a fan of the gland rings no matter what. You have two options:

1. check/use/or obtain a good manifold assembly and get it surfaced properly. That also includes surfacing the mounting ears slightly with an end mill if possible.

2. get the new repro manifolds if you don't have another suitable one,, and as Mitch said that many mount them without surfacing. I usually find they can stand some touching up.

Use the gasket of your choice... I like the 1- piece steed clad felpro gasket for go cars.. or if you are inclined use the copper clad gasket. Tighten using the proper washers/nuts - as previously stated and snug them evenly. recheck again a couple of times after use. AS mitch indicated NO sealer.. it will burn away anyway and then be worse. I don't use a torque wrench on these but use my feel of experience. Use a torque wrench to 35-40 if you feel inclined.

That should take care of it... after all the years I have had only 2 blocks that had a poor true flat surface on the block area. It can happen but is not common from my experience.

Good luck!
Larry Shepard

[Indiana A. Lover]

45 is too tight You will twist the bolt off Stop at 35 Max.

[hoof]

I just put a new gasket on mine and it wouldn't get anywhere near the block with the gland rings in place. My car is a '29 and while there are recesses in the block and manifold they are no where near deep enough. I used the gland rings only to align the gasket (new type) then took them out.

When I bolted it down there was a significant gap at the center two exhaust ports. I kept going back over the course of several days and tightening the nuts. Not overtightening them, just keep snugging them up. They would move a flat or two with little effort each time then get tight. After a certain amount of time they stopped getting tighter and the gasket sealed.

I am not saying this is correct, or even a good idea, but it worked for me. I don't know if the gasket kept compressing where it was tight or if the manifold pulled tight a little at a time, but it worked.

Your mileage may vary.
CHAZ

[Al 29Tudor]

We just tried to use gland rings on the exhaust manifold of a members car and couldn't.
The ports on the manifold were not inline - back end of manifold sagged but we were able to get the manifolds to seal using the two, three port gaskets.
Al Leach

[RonC]

Buy the repro exhaust and intake manifolds. They are excellent. Add an Aries muffler and be done with leaky exhaust and enjoy the Model A engine sound as it should sound. 45lbs is way to much you probably warped your manifolds. I use 25-30lbs evenly torqued from the center out. You only need to seal the assembly to the block with slight gasket pressure. Use a think coat of spray tack and gland rings. Test the fit without a gasket and the gland rings installed first. Make sure the manifolds fit flush to the block no rocking. Otherwise the rings are too thick and you will crack the mounting ears.

[BILL WILLIAMSON]

Originally Posted by Indiana A. Lover

45 is too tight You will twist the bolt off Stop at 35 Max.

Indiana,
They WON'T twist off @ 45 Ft Lbs, they're the SAME size as the HEAD studs "Someone" said the High Temp Exhaust Sealer would blow or burn out, IT WON'T I only ever recommend stuff that has worked for me, personally. Take it or leave it!
Bill Tight

[Chuck Sea/Tac]

If you have the brass nuts, they'll strip. Also have to be careful of breaking an ear.

[tbirdtbird]

1) Les' books have many errors. The manifold spec is one of them, as several experienced posters have noted. I am with #11 all the way:
"45lbs is way to much you probably warped your manifolds. "
And crushed your gasket to death.
Those manifolds also need to expand and contract due to heat (a LOT) while they live under those over-torqued nuts.....and while you may not strip the studs, you can easily end up cracking a manifold or breaking off an ear.

I have used brass exhaust manifold nuts on every vintage car/truck I have owned so that I do not have to fight seized/rusted steel ones down the road. They have never stripped in my hands. But, over-torque them and they will strip

[Indiana A. Lover]

Bill I am saying Manifold bolts go threw a lot of Hot and cold cycles, which weakens the metal. I am baseing my Reply on people rarely put in new manifold bolts, it is cheap insurance agaist broken heart aches and high blood pressure. Watching the corn and soybeans turn Golden Good driving Weather!!

[James Rogers]

Originally Posted by Indiana A. Lover

45 is too tight You will twist the bolt off Stop at 35 Max.

How do you figure this? The manifold bolts are the same size and diameter as the head studs and they torque at 55#. The only difference is the length of the stud and the shorter stud should stand more torque than, say, the outlet studs.

[BILL WILLIAMSON]

On one Guys' intake manifold, The "ears" were THICKER than on the intake manifold.
He "carefully" ground reliefs, in the side of the washers, "carefully" indexed them & it WORKED.
When I torque them, I leave the 2 bolts that hold them together, slightly loose & torque them in stages, up to 55 Ft Lbs.
The ends of the manifold, @ # 1 & # 4 are the pesky ones for leaks. Too bad they didn't cast an extra mounting ear, at the ends. I use a CHEEP Stethescope, with an open hose, to find leaks. It'll find VACUUM leaks too! It'll SCREAM like a BANSHEE! Harbor Freight has them for $2.99, sometimes. (OH, you can stick it in your NOSE & hear yourself BREATHE, so it's well worth the $2.99)
Bill Quiet