Exhaust Manifold Gasket

Caryc

Well-known Member
Well, I hear the ticking sound again which indicated a leaking manifold the last two times. I replaced the manifold twice now. I always put the manifold gaskets on dry so maybe that's my problem.

Anyway, I've already ordered a new manifold and I got some Permatex Ultra copper gasket maker. I plan on coating both sides of the gaskets this time.

Now, about the gaskets. They have a shiny side and a dull side. The shiny side was the "up" side when they punched them out and the dull side was the die side. Does it make any difference which side goes toward the engine? I don't remember what I did the last time I did it.
 
I don't remember which side I had facing the block . I did use ultra copper rtv on the gaskets and around the bevel on the exhaust pipe before clamping it tight .

Hardest thing was having to let it cure for 24hr before starting the motor so I would not blow it out .

Some people like to take a small punch or drill bit to make indents for the rtv to grab .

Seems like it lasted about a year before it blew out again .

I think a man would do good to use a 2" or 3" angle die grinder with 100 grit paper and work that whole surface front to back .

Running the manifold on a sheet of sand paper on top of a hard flat table could also show high spots .
 
(quoted from post at 17:09:43 03/14/19)
Now, about the gaskets. They have a shiny side and a dull side. The shiny side was the "up" side when they punched them out and the dull side was the die side. Does it make any difference which side goes toward the engine? I don't remember what I did the last time I did it.

Whichever side will withstand the most heat goes to the manifold side . . . usually the shiny/metallic side.
 

Well, thanks guys, but now I have two different opinions so I don't know who to believe.
 
(quoted from post at 07:25:02 03/15/19) I don't remember which side I had facing the block . I did use ultra copper rtv on the gaskets and around the bevel on the exhaust pipe before clamping it tight .

Hardest thing was having to let it cure for 24hr before starting the motor so I would not blow it out .

Some people like to take a small punch or drill bit to make indents for the rtv to grab .

Seems like it lasted about a year before it blew out again .

I think a man would do good to use a 2" or 3" angle die grinder with 100 grit paper and work that whole surface front to back .

Running the manifold on a sheet of sand paper on top of a hard flat table could also show high spots .

Start it up the heat will cure it rite fast...
 
(quoted from post at 07:25:02 03/15/19)

Start it up the heat will cure it rite fast...

Yep and after heating I've always gone back for a re-torque and later another double-check. Works great for exhaust pipe donuts too. Never had a leak.

I plane the faces with emery on a sheet of plate glass :)
 
An N-Series Tractor??? Exhaust manifold gaskets are just plain paper -I've never seen metallic ones except only for the head. Plus, they go on dry, no gasket goop required, as it will just burn anyway. There are two gaskets, one on each side, not stacked on top. How do you determine a 'clicking' noise is a defective manifold? Are you hearing a tappet or loose valve? Where is it leaking? Did you scrape off all the old gasket material on the block first? Manifold nuts are 7/16-20 BRASS hex nuts torqued at 27 ft/lbs and use steel washers. Are you using the correct scale on your torque wrench?

The brass nuts were used because steel will work harden after heating up and cooling down several times thus making it difficult to remove them when it comes time. The 7/16-20 thread size torque spec for brass is 27 ft/lbs. If you use steel nuts, Grade 2 torque spec is 35 ft/lbs and Grade 5 is 55 ft/lbs. You can find these in any Machinery's Handbook or online at any fastener supplier. Use steel lockwashers. Here is a LINK to a popular parts supplier with a brass nut and washer kit. 5/8 and/or 11/16 is dimension AF ( Across Flats ) of nut and has no bearing on torque value. You really don't need to put any gasket sealer on the manifold, in my opinion, but that's your call and do not use two gaskets per side because your manifold leaks. Also, do not use any oil lube or Anti-Seize on the brass manifold stud threads as this will affect torque as well as old, worn stud threads. Since true torque is measured with un lubed NEW parts, you don't really need a torque wrench either. I've replaced many exhaust manifolds without a gasket sealer nor any brass nuts. I will then use steel nuts and apply a dab of Anti-Seize on them and tighten down with a socket wrench until I 'feel' they are good. It's not rocket science and I'm sure many an old farmer did the same thing back in the day. If you are trying to use an old manifold due to leaking, chances are the manifold has worn a passage around port #4 nearest the exhaust end where it gets the hottest. In my opinion, since you have everything torn down anyway -carb off, manifold off, etc why not just replace the manifold with a new one? Why put a Band-Aid on it now only to have to redo the project again in a month or three? Do It Right The First Time...

Tim *PloughNman* Daley(MI)
 

Your parts supplier is selling cheap junk if yours is just paper...

Ultra Red copper will not only help seal imperfections it turns into a slick powder that lubes the manifold and engine block during expansion and contraction... We already know what installing them dry does :(... If its paper it sure is some abrasive stuff...
 
I've read all kinds of tricks to getting flat exhaust gaskets to seal on cars.

A: Use two and stack them
B: Soak the gaskets in water before you install them
C: Coat the gaskets with something (there's a lot of choices)
D: Use no gasket and just sealer
E: ETC.......


Honestly I've had the most luck with just installing them dry and using a quality bolt (which in the case of an N is a stud) and then re-torque several times after several heat cycles (you'd be surprised how much they loosen up as that gasket conforms to the gap).
 
(quoted from post at 03:31:49 03/15/19) An N-Series Tractor??? Exhaust manifold gaskets are just plain paper -I've never seen metallic ones except only for the head. Plus, they go on dry, no gasket goop required, as it will just burn anyway. There are two gaskets, one on each side, not stacked on top. How do you determine a 'clicking' noise is a defective manifold? Are you hearing a tappet or loose valve? Where is it leaking? Did you scrape off all the old gasket material on the block first? Manifold nuts are 7/16-20 BRASS hex nuts torqued at 27 ft/lbs and use steel washers. Are you using the correct scale on your torque wrench?

The brass nuts were used because steel will work harden after heating up and cooling down several times thus making it difficult to remove them when it comes time. The 7/16-20 thread size torque spec for brass is 27 ft/lbs. If you use steel nuts, Grade 2 torque spec is 35 ft/lbs and Grade 5 is 55 ft/lbs. You can find these in any Machinery's Handbook or online at any fastener supplier. Use steel lockwashers. Here is a LINK to a popular parts supplier with a brass nut and washer kit. 5/8 and/or 11/16 is dimension AF ( Across Flats ) of nut and has no bearing on torque value. You really don't need to put any gasket sealer on the manifold, in my opinion, but that's your call and do not use two gaskets per side because your manifold leaks. Also, do not use any oil lube or Anti-Seize on the brass manifold stud threads as this will affect torque as well as old, worn stud threads. Since true torque is measured with un lubed NEW parts, you don't really need a torque wrench either. I've replaced many exhaust manifolds without a gasket sealer nor any brass nuts. I will then use steel nuts and apply a dab of Anti-Seize on them and tighten down with a socket wrench until I 'feel' they are good. It's not rocket science and I'm sure many an old farmer did the same thing back in the day. If you are trying to use an old manifold due to leaking, chances are the manifold has worn a passage around port #4 nearest the exhaust end where it gets the hottest. In my opinion, since you have everything torn down anyway -carb off, manifold off, etc why not just replace the manifold with a new one? Why put a Band-Aid on it now only to have to redo the project again in a month or three? Do It Right The First Time...

Tim *PloughNman* Daley(MI)

Tim, you may want to go back and read the OP again.
 
Use the best quality gasket you can get, but most important in my experience is to torque all the nuts after the engine has cooled from the first heating cycle and then again after a few uses; torque while cold. Reason: the heating cycle squeezes the gasket as the metal expands on both sides, and then contracts while cooling; so there is some microscopic sponginess in the gasket after the first heat/cool cycle, so torque it then and squeeze it back. A nut may make a half a turn or so. A few more cycles and there may be another 1/8 or quarter turn; then you're probably OK. Of course, if the manifold is not true in its flatness, no gasket will hold forever.
 
(quoted from post at 05:43:05 03/15/19)
(quoted from post at 03:31:49 03/15/19) An N-Series Tractor??? Exhaust manifold gaskets are just plain paper -I've never seen metallic ones except only for the head. Plus, they go on dry, no gasket goop required, as it will just burn anyway. There are two gaskets, one on each side, not stacked on top. [color=red:49b653a9cf][b:49b653a9cf]How do you determine a 'clicking' noise is a defective manifold? Are you hearing a tappet or loose valve?[/b:49b653a9cf][/color:49b653a9cf] Where is it leaking? Did you scrape off all the old gasket material on the block first? Manifold nuts are 7/16-20 BRASS hex nuts torqued at 27 ft/lbs and use steel washers. Are you using the correct scale on your torque wrench?

The brass nuts were used because steel will work harden after heating up and cooling down several times thus making it difficult to remove them when it comes time. The 7/16-20 thread size torque spec for brass is 27 ft/lbs. If you use steel nuts, Grade 2 torque spec is 35 ft/lbs and Grade 5 is 55 ft/lbs. You can find these in any Machinery's Handbook or online at any fastener supplier. Use steel lockwashers. Here is a LINK to a popular parts supplier with a brass nut and washer kit. 5/8 and/or 11/16 is dimension AF ( Across Flats ) of nut and has no bearing on torque value. You really don't need to put any gasket sealer on the manifold, in my opinion, but that's your call and do not use two gaskets per side because your manifold leaks. Also, do not use any oil lube or Anti-Seize on the brass manifold stud threads as this will affect torque as well as old, worn stud threads. Since true torque is measured with un lubed NEW parts, you don't really need a torque wrench either. I've replaced many exhaust manifolds without a gasket sealer nor any brass nuts. I will then use steel nuts and apply a dab of Anti-Seize on them and tighten down with a socket wrench until I 'feel' they are good. It's not rocket science and I'm sure many an old farmer did the same thing back in the day. If you are trying to use an old manifold due to leaking, chances are the manifold has worn a passage around port #4 nearest the exhaust end where it gets the hottest. In my opinion, since you have everything torn down anyway -carb off, manifold off, etc why not just replace the manifold with a new one? Why put a Band-Aid on it now only to have to redo the project again in a month or three? Do It Right The First Time...

Tim *PloughNman* Daley(MI)

Tim, you may want to go back and read the OP again.

Correct.

About your question above in red, I determined that it was a leaking manifold at #4 because I could hear the clicking and feel the air puffing out of it when I stuck my finger close by it.

That was on the last manifold. On this one, the clicking is not as loud because I knew the sound and caught it early. I could not feel the leak with my finger but I have a mechanics stethoscope set. One of the attachments is for detecting air leaks. I put the "cup" by number four and I could hear the air chuffing out of it.

I also have a new manifold on the way.

VdNN52w.jpg
 
I just logged in and saw your post. Had the same problem on my 8NC and blew out 2 gaskets, So instead of replacing the manifold,I replaced the whole exhaust with one of those vertical mount exhaust systems and it fixed it right away. I'm pretty sure the original exhaust was partially or fully blocked causing a pressure buildup and of course that pressure's going to find the weakest point to escape. Haven't had an issue since.

I'm thinking all kinds of animals like to build nests and make homes in there. So with the vertical mount you've got that louvered cap that can stop that?
 

my N came with a burned out manifold and a vertical exhaust. don't overthink this ;)
 
They're metal. I just bought some this week. You just put them on and torque the bolts and you're good for about 15 more years.
 

A magnet test will confirm that... BTW these engines are not spring chickens they are old and worn and need all the help they can get when sealing them up... I have had the manifold off 50 are more some I have had off 5 years later the RTV trick saves the gasket and manifold from ware and tear...

In a perfect world no manifold gasket on the exhaust side would be needed they would self seal like they do on millions of applications...

So Y'all dry fitters take your chance and rub on yer manuals for your backup plan I am gonna insure mine with a lite coat of ultra red life is good...
 
(quoted from post at 06:01:40 03/17/19)
A magnet test will confirm that... BTW these engines are not spring chickens they are old and worn and need all the help they can get when sealing them up... I have had the manifold off 50 are more some I have had off 5 years later the RTV trick saves the gasket and manifold from ware and tear...

In a perfect world no manifold gasket on the exhaust side would be needed they would self seal like they do on millions of applications...

So Y'all dry fitters take your chance and rub on yer manuals for your backup plan I am gonna insure mine with a lite coat of ultra red life is good...

The gaskets I got right here from YT are metal. A magnet will stick to them. Below is a picture of the "Ultra Copper" that I got for the job. Is this not the right stuff?
 
(quoted from post at 06:01:40 03/17/19)
A magnet test will confirm that... BTW these engines are not spring chickens they are old and worn and need all the help they can get when sealing them up... I have had the manifold off 50 are more some I have had off 5 years later the RTV trick saves the gasket and manifold from ware and tear...

In a perfect world no manifold gasket on the exhaust side would be needed they would self seal like they do on millions of applications...

So Y'all dry fitters take your chance and rub on yer manuals for your backup plan I am gonna insure mine with a lite coat of ultra red life is good...

Darn, forgot the picture.

KVdqhZz.jpg
 

yep...When done and you have a food vacuum system pack that tube they don't have a long shelf life after they are opened... Are put in a sip lock bag....
 
(quoted from post at 15:26:16 03/17/19)
yep...When done and you have a food vacuum system pack that tube they don't have a long shelf life after they are opened... Are put in a sip lock bag....

You're not suggesting that I may have to do the job over again in a month are you? :mrgreen:

I'm still waiting on the manifold that should be here on Wednesday.
 

Well that's up to the installer YOU :lol: That RTV does not have much use other than exhaust its your call if you want to prolong its life span...
 
(quoted from post at 18:18:13 03/17/19)
Well that's up to the installer YOU :lol: That RTV does not have much use other than exhaust its your call if you want to prolong its life span...

What exactly does RTV stand for? I don't see that anywhere on the tube.
 

[b:f6d0f3317a]"Exhaust manifold gaskets are just plain paper"[/b:f6d0f3317a]

i just picked up a set of gaskets. they're quite heavy and have a metal layer.
 
(quoted from post at 08:29:21 04/30/19)
[b:1e7b16cf75]"Exhaust manifold gaskets are just plain paper"[/b:1e7b16cf75]

i just picked up a set of gaskets. they're quite heavy and have a metal layer.

The most recent manifold gasket that I have done was light weight, just paper. Most have been very dense material. Some have had a metal layer.
 

i understand that SOME are paper - but i'm surprised someone so knowledgeable wouldn't know that plenty are more than that.
 
(quoted from post at 09:18:09 04/30/19)
i understand that SOME are paper - but i'm surprised someone so knowledgeable wouldn't know that plenty are more than that.

HFJ, maybe a case of short attention span while reading?
 

sorry for the confusion. i was referring to the source of "Exhaust manifold gaskets are just plain paper."
 

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