Anti seize on manifolds

[Business_As_Usual]

Just installed both manifolds on my 40’ Special Business Coupe. Used 3 piece gasket, but did not put anti seize on the gaskets on either side of the gasket. Should I have put anti seize on the head side of the gaskets?  Thinking about taking it off again and applying the anti seize as mentioned above. Also used brass nuts on the studs holding the manifolds in place. Any comments on that would also be appreciated. Thanks, Tom

[Morgan Wright]

Did you use the copper gaskets or the other stuff?

 

Anti-seize is a hydrocarbon lubricant with additives like copper filings or graphite, the hydrocarbons burn off at high temperatures leaving the additives behind so the bolt or part can be removed at a later date, and not seize. Manifold gaskets for the 1940 engine, the copper gasket is a metal crush gasket which is designed to make a perfect seal at high temperatures, and it doesn't need Anti-seize because it's copper. The other material they use for manifold gaskets I don't know about, it usually just burns up and you get copper gaskets.

 

Brass nuts are a good idea, I think the OE used brass nuts.

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Edited September 25, 2022 by Morgan Wright (see edit history)

[Joseph P. Indusi]

I used a mixture of graphite and oil on both sides of the copper clad gaskets on my 53 straight eight.  I tried brass nuts but I could not get the torque on the nuts to spec before they stripped out.  
An important thing is to use the correct washers under the nuts that have a very small contact area on the exhaust manifold.  The idea is to let the manifold move a little as it goes from cold to hot. 
Joe, BCA 33493

[Daves1940Buick56S]

Mark Shaw did a great write up on this. Use belleville washers and the copper based hi temp antisieze. Have to look at the tube in my shop to get the name. I used the copper faced gaskets. Worked fine on my 1940 248.

[DonMicheletti]

I have to question the use of bellville washers on exhaust manifolds.  Basically, bellvills are just springs and manifolds can get hot enough to cause them to loose temper. (I have seen manifolds red hot). Same with the use of lock washers.

I'd stay with the thick washers as original.

Of more importance is that the "ears" of the manifolds be the same height - a washer can't adequately compensate for much difference.

[Business_As_Usual]

Thanks for all your responses.  I’m going to take it apart and use the mixture of graphite and oil on the gaskets I have now (the other stuff) and will get copper gaskets when these need replacement.  When I took off the manifold the front stud broke off inside the hole. I was only using a 3/8 drive ratchet with hardly any effort at all. The rest came out unbroken, nut and stud together.  They were not tight at all.
I’m not a welder, so I drilled it out and tried an easy out. I also used a left hand drill bit and neither worked. I had to buy an pneumatic right angle drill and a Time-sent kit. Not cheap, but a really nice repair. Nice when things go like they should every once in a while.  I do have the Belleville washers, which I believe are original. 

[Lawrence Helfand]

16 hours ago, Business_As_Usual said:

Just installed both manifolds on my 40’ Special Business Coupe. Used 3 piece gasket, but did not put anti seize on the gaskets on either side of the gasket. Should I have put anti seize on the head side of the gaskets?  Thinking about taking it off again and applying the anti seize as mentioned above. Also used brass nuts on the studs holding the manifolds in place. Any comments on that would also be appreciated. Thanks, Tom

My 41 Century has a very long manifold with twin carb setup. I used all the tricks I know from decades of fear of the cracked manifold. First I use a thick copper gasket and there are a few available but go for the slightly more $ thicker one. I make a slurry of graphite and motor oil and apply to all sides. I use Belville (spring) washers as sold on ebay for Jeep Wranglers which like the Buick has a lot of movement in the heat cycle and these washers maintain tension that allows some creep. Most important with that fat gasket is lower torque setting then factory. I use 18 lbs and vacuum is great which makes for happy windshield wipers. Also always tighten incrementally from center out. I use a standard nut and anti seize on threads. 

[Morgan Wright]

I made a mistake when I mentioned brass nuts, I found them where the exhaust manifold met the exhaust pipe. Not on the studs that attached the manifold to the engine.

 

Sorry it's been a few years.

[RiKi5156B]

Ever since my race car days from 80s to 00s I've used stainless everywhere in the exhaust. No matter how long they are there crack them loose with a wrench and  spin off by hand