Bad manifold gaskets

stewgee

stewgee

Member
Hello all
Can someone tell me what the best exhaust/intake gaskets are. I have had a heck of a time getting my 30 A going after installing all new gaskets from the complete set from Mac's. I just pulled the intake and exhaust manifolds and the gaskets are shot. There is signs of leakage from all ports and a portion of the rear gasket was blown away. All manifolds bolts were torqued per specs. Any thoughts would be welcomed.
 
stewgee said:
Hello all
Can someone tell me what the best exhaust/intake gaskets are. I have had a heck of a time getting my 30 A going after installing all new gaskets from the complete set from Mac's. I just pulled the intake and exhaust manifolds and the gaskets are shot. There is signs of leakage from all ports and a portion of the rear gasket was blown away. All manifolds bolts were torqued per specs. Any thoughts would be welcomed.
Click to expand...

Are your manifold gasket surfaces flat and parallel with each other? Are you using the gland rings? Is your exhaust manifold 'drooping' on the back end?

I like the late '31 copper gaskets. https://www.snydersantiqueauto.com/copper-manifold-gaskets
 
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If they came in a kit set, they would be the fiber ones. I think a lot of suppliers sell them that way. You need to get the GOOD copper faced ones, along with gland rings (google "fordbarn; gland rings). The hard fiber ones do not hold up and burn out just as you are experiencing.
 
I had the same problem. I used Snyder's copper manfold gasket A9433-C with Permatex Ultra Copper Silicone sealant. No problems since. BTW make sure with a steel straight edge you have no warping on the manifold or the block.
 
I have had bad luck with all the manifold gaskets except the steel impregnated, waffle pattern. These last well and don't burn out.

A's Always
Dave
 
Here's are some tips for installing the manifold gaskets:
> Take out the 2 bolts connecting the intake manifold to the exhaust manifold;
> Install the manifolds being sure to use gland rings in each exhaust port;
> Fit each ring beforehand, so it has a 0.06" end gap for expansion. The expansion gap prevents a ring from buckling, going into the exhaust pipe and winding-up in the muffler;
> Snug the manifold attachment nuts, but do not torque them to an amount that flattens the cup washers. The cup washers are actually springs that take-up thermal expansion which tends to loosen the manifold connections to the block;
> There is likely to be a gap between the intake & exhaust manifold surfaces where the bolts were removed:
o Shim the gap closed with metal sheet stock to retain the hot spot conduction heat transfer function for warmup of the intake manifold or,
o Leave the gap open and loosely install the 2 bolts connecting the manifolds so it looks correct or,
o Leave the 2 bolts out.



Running with a gap between the manifolds at the hot spot enhances performance because the fuel mixture will be cooler, thus denser. On the other hand, cold start warmup will be longer if there is a gap at the hot spot.



I have seen many cracked-out bolt tabs on intake manifolds where the 2 bolts go because of bending loads that occur when joined manifolds are clamped-up to a compressible exhaust gasket. Machining the manifolds as a set reduces the clamp-up loads, but not totally.
 
stewgee said:
Hello all
Can someone tell me what the best exhaust/intake gaskets are. I have had a heck of a time getting my 30 A going after installing all new gaskets from the complete set from Mac's. I just pulled the intake and exhaust manifolds and the gaskets are shot. There is signs of leakage from all ports and a portion of the rear gasket was blown away. All manifolds bolts were torqued per specs. Any thoughts would be welcomed.
Click to expand...



I have always had great luck with the Felpro MS 2388 S, which you can order from most auto suppliers like Advance Auto. They last a long time and seal very well.
 
31 Vicky said:
I have had bad luck with all the manifold gaskets except the steel impregnated, waffle pattern. These last well and don't burn out.

A's Always
Dave
Click to expand...

Same with me. The manifolds should be surfaced unless new. Also, I use the gland rings but filing them a little to ensure the gasket seats.
 
I will make the assumption that you are using gland rings in the four exhaust ports and the rings won’t allow the manifold to seat properly between the manifold and block causing the gasket to leak and blow out.

Remove the manifold and clean both block and manifold surfaces. Check both for depressions in the ports. Clean them out of any carbon particles, reinstall the manifold with the gland rings in place but without a gasket and snug the manifold until you feel resistance then stop. Take a feeler gauge and check the clearance between the manifold and block. If there is no clearance use the gasket of your choice. I prefer the copper ones. If you have a clearance use a gasket that is a least X2 what the feeler gauge reading is. My reason I do it this way is you don’t know to what extent both surfaces have been milled in the past. PS: disconnect the muffler first.
Sofield
 
I am of the opinion that gland rings do not matter. I use copper 31 gaskets from A&L and have never had a failure.
Also as mentioned the surface must be flat.
John
 
The gland rings are not there to prevent blow out, they are there to support the manifold to keep it from sagging. Except for a short time in 29 or 30 and just a few engines at that, all 4 cylinders up to 34 used the gland rings.



Once again I am going to repeat, most all the full engine gasket kits I have seen come with the fiber type intake/exhaust gaskets which I bet is what he is using. The better type manifold gaskets are an extra cost item.

Lots of good advice being given here.
Now if only the person that asked the question would supply an updates.
 
I’m with John and Dave. I have installed hundreds of manifolds and have surface them and I no longer use gland rings for a number of reasons. Fit, pia, etc. If you have a good surfaced manifold and use the steel clad 1 piece manifold or copper set the manifold is fine anc will last for many years. The gland rings can actually cause issues on some manifolds depending on how much recess is left in them, and alignments in already warped manifolds.

Just my 2 cents with after having done mani and knowing the history of how they are doing.
Larry Shepard
 
To sum it up - 'If the gasket fails," it's the exhaust manifold". Also, if all of the rings can't go in - It's the exhaust manifold. Not so long ago many of the manifolds were lousy, but they are really good now. And the cure is: a new one.
 
Bob Bidonde said:
Here's are some tips for installing the manifold gaskets:
> Take out the 2 bolts connecting the intake manifold to the exhaust manifold;
> Install the manifolds being sure to use gland rings in each exhaust port;
> Fit each ring beforehand, so it has a 0.06" end gap for expansion. The expansion gap prevents a ring from buckling, going into the exhaust pipe and winding-up in the muffler;
> Snug the manifold attachment nuts, but do not torque them to an amount that flattens the cup washers. The cup washers are actually springs that take-up thermal expansion which tends to loosen the manifold connections to the block;
> There is likely to be a gap between the intake & exhaust manifold surfaces where the bolts were removed:
o Shim the gap closed with metal sheet stock to retain the hot spot conduction heat transfer function for warmup of the intake manifold or,
o Leave the gap open and loosely install the 2 bolts connecting the manifolds so it looks correct or,
o Leave the 2 bolts out.

Running with a gap between the manifolds at the hot spot enhances performance because the fuel mixture will be cooler, thus denser. On the other hand, cold start warmup will be longer if there is a gap at the hot spot.

I have seen many cracked-out bolt tabs on intake manifolds where the 2 bolts go because of bending loads that occur when joined manifolds are clamped-up to a compressible exhaust gasket. Machining the manifolds as a set reduces the clamp-up loads, but not totally.
Click to expand...


I've read posts of homemade gland rings made from seamless steel pipe. Do those need to be cut to provide end gap for thermal expansion?
 
My fiber gaskets blew out. The block and manifolds are flat and I used the rings. I switched over to the copper composite ones and have no problems to date. The fiber ones looked burnt and were hard and brittle.
 
nkaminar said:
My fiber gaskets blew out. The block and manifolds are flat and I used the rings. I switched over to the copper composite ones and have no problems to date. The fiber ones looked burnt and were hard and brittle.
Click to expand...

Did you buy the rings from one of the vendors or did you make them yourself?
 
dmaxweb said:
I've read posts of homemade gland rings made from seamless steel pipe. Do those need to be cut to provide end gap for thermal expansion?
Click to expand...

I'm confused. The manifold is cast iron, so the linear thermal expansion coefficient is 5.8. The rings are mild steel, so the coefficient is ~6.5-7.0. That's close enough that the expansion you'd get at normal exhaust temperatures is like going from a slip fit to an interference fit. Unless you're needing to drive your homemade rings in with a hammer, it doesn't seem like you'd need to worry about buckling due to expansion.
 
D Max, I bought the rings. They are split and I stretch them a bit to make them stay in the block when I put the manifolds on.

Alex, I think this all assumes that the rings get hotter than everything else. Without data I am not sure they do. If anyone out there wants to test this then they can weld some thermocouples to the rings and manifold and go for a drive. Is there any evidence of buckling rings?
 
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