Best Manifold Sealing Options?

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Feb 24, 2016
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Ok LC Gurus,
Here’s the deal, I’m putting my freshly rebuilt 1975 2F back together and I need my headers to seal up right this time. I’ve always had trouble getting a correct seal on the intake and headers (at least since my dad put headers on it when he owned it).

At the advice of my mechanic, I’ve cut the main bar of the headers to hopefully allow them to pull up tighter. He machined my intake facing which had a minor warp.
Now my next question is should I grind down the inner mating area of the exhaust ports to a more flat surface?

Also, are these the correct studs and are they installed properly? I’ve read about shouldered studs but I’m not sure if these are “shouldered” or not.
All but the middle two appear to not be seated properly (to me).

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65swb45

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Cart before the horse. Now the header flange has been cut, there’s no way to tell if the gap is how wide they cut it, or if the header ‘opened up’ when it was cut. And it’s 3 times as likely that it won’t lay flat on the cylinder head.

You need to test fit the header as it stands NOW to see if it lays flat to the head, and to see if the cuts for the manifold studs are even close enough for nuts and washers to hold the header without leaking. Without the structural integrity of a solid flange, you almost have to have twice as many studs to anchor a header of this design type.

If your mechanic thinks that you can simply snug everything up and make it happy, he obviously has no experience with this brand of header either. The tubes are NOT mandrel bent, and torquing that header into place will only lead to premature cracking. That’s why I don’t sell them.
 
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Cart before the horse. Now the header flange has been cut, there’s no way to tell if the gap is how wide they cut it, or if the header ‘opened up’ when it was cut. And it’s 3 times as likely that it won’t lay flat on the cylinder head.

You need to test fit the header as it stands NOW to see if it lays flat to the head, and to see if the cuts for the manifold studs are even close enough for nuts and washers to hold the header without leaking. Without the structural integrity of a solid flange, you almost have to have twice as many studs to anchor a header of this design type.

If your mechanic thinks that you can simply snug everything up and make it happy, he obviously has no experience with this brand of header either. The tubes are NOT mandrel bent, and torquing that header into place will only lead to premature cracking. That’s why I don’t sell them.
well that's not what i wanted to hear, but thank you. the header ports were not level/straight initially. i hung it on the studs this afternoon, but didn't tighten it at all. it "looks" like it will pull up tight-ish. I was planning to run a bead of copper sealant in addition to the gasket.

SO, since i've cut the flange, is there any salvaging them? or is it just a matter of mount them and see if they leak?
 
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Test fit together without gasket. See what your gaps are like. Most likely you’ll need washers cut in half and make up the gap so they can seal ‘together’ when torqued down. That mixed with a clean bead of ultra copper on a quality manifold gasket should do the trick.
 

Shark56

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Looks like a Remflex gasket is in your future. Don't over tighten it!

 
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Test fit together without gasket. See what your gaps are like. Most likely you’ll need washers cut in half and make up the gap so they can seal ‘together’ when torqued down. That mixed with a clean bead of ultra copper on a quality manifold gasket should do the trick.
That's how I had it originally mounted. They're a SOB to get set in the gaps right and to file down to fit, but i'm gonna start with some new washers
 
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Looks like a Remflex gasket is in your future. Don't over tighten it!

I've looked at these the other day actually in my searching and reading. Is this the one that is abnormally thick with several layers of soft metal to crush/form a seal? And would you recommend still using copper sealant as well?
 
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I've looked at these the other day actually in my searching and reading. Is this the one that is abnormally thick with several layers of soft metal to crush/form a seal? And would you recommend still using copper sealant as well?
Yes that’s the abnormally thick gasket. Ultra copper isn’t a bad move with the exhaust ports and ensuring the correct torque on the nuts.
 
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perfect, i'm reading up more on them right now and about to order one! this has been one of my bigger concerns of putting the truck back together. Next is figuring out how to wire in my DUI 👨🏻‍🔧
 

pjohnson

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I would give it a shot with a normal gasket and Permatex spray on copper gasket sealer. I would never use a squeeze tube sealer on intake/exhaust.

To me, an extra thick gasket just leaves room for gaps from imperfect torquing, not to mention heat cycles causing expansion/contraction.

If it all ultimately fails, get yourself a new header or exhaust manifold and have a machine shop mill flat the intake and exhaust together. Install with a new oem gasket.
 

Downey

 
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Ok, I'll beat the horse again. Having sold zillions of Landcruiser Headers, and dealing with zillions of guys who have a leaking Header, I still believe our remedy is the best on the market- - -use almost any quality gasket, paint Head, Header, and both sides of the gasket with Coppercoat (don't know if you can still get the lacquer based Coppercoat, it was the one that baked-on nicely with engine heat), then tighten until you think the studs will break off in the Head (the hardened stud should not break, the softer nut should strip in worst case). This was always the total remedy, only problem was when you removed the Header you had one hell of a gasket scrapping job on your hands- - -but this is what kept the Header "glued" to the engine.
 
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I would lightly drag a flat file across the header flange and make it at least resemble flat. Also There used to be a couple of places that would make copper gaskets. Those work when not much else will.
 

thebigredrocker

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I bet 65swb45 has OEM exhaust manifolds in stock if you decide go the route 3Puppies suggested.

I went with the program Mark W and FJ40Jim seem to recommend. FelPro, surfaces machined flat and no goop. No more Vac leaks
I swear by Felpro intake gaskets. And swear at Victor.

Double gasketing is just a tool for sealing warped or damaged manifolds. works well when a single is not thick enough. But a single quality gasket is usually enough. No sealant will survive the heat of the exhaust for long anyway, so do not bother.

Mark...
I have had nothing but good experience with Felpro gaskets for the last 30+ years.

Mark...
No, absolutely not.

One good Felpro gasket, flat manifolds, good fasteners, torqued to the top end of the spec.
The Felpro graphlex gasket has been out for many years now, and has proven to be the best solution to the difficult manifold sealing problem. It's so good that Toyota has replaced the sh1tty punched foil gasket with the graphlex one.
 
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@Runnin On Empty
Are the threads all good? From a distance this one looks worn down in the middle.


View attachment 2070378
That’s my concern as well, I’ve never had an issue with them, but I do want to replace them.
I’ve been trying to find the size and thread count of them (i have my numbers written down at home but don’t remember off hand). I’ve looked for part numbers as well, best I could find was PN 90116-10042
 

65swb45

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That’s my concern as well, I’ve never had an issue with them, but I do want to replace them.
I’ve been trying to find the size and thread count of them (i have my numbers written down at home but don’t remember off hand). I’ve looked for part numbers as well, best I could find was PN 90116-10042
I’m not at the shop to check, but I think that number is for the 10mm stud. A 75 with a 2F should have 12mm studs, so your PN should have a 12 in it.
 
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