When to use gasket sealant

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When to use gasket sealant

Post by rustbelt »

This is probably basic knowledge but I have to ask.
Is there a common, standard guideline on when to use/not use a sealant on a gasket?
For an example: when involving gas - no sealant; involving oil - use sealant.

1. I've removed the covers on my 1965 110 to change out the fan bearing and am now ready to apply a gasket to the motor, followed by the top ventilator cover, another gasket and finely the top block cover with the new fan bearing. Should I apply sealant to the gaskets (if so, to both sides of each?) or not?

2. Soon I'll be dropping the oil pan.... sealant on the gasket or not?

3. How about on the new carb gaskets?

Thanks for the help.

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Re: When to use gasket sealant

Post by terribleted »

I normally install all these gaskets dry. If the surfaces of the top of the block and the bottom of the top block cover have pitting or imperfections I might use some Permatex #2 in that location. For the oil pan I always use a quality cork and rubber composite gasket with a factory pan and Clark's thicker paper gasket with an aluminum pan. Biggest thing on the oil pan using the cork/rubber gasket is do not over tighten, tighten only enough until you see the gasket edge between the pan and the gasket start to squish out and no more. Same routine here, if the surfaces being joined have some imperfections I might use some Permatex #2 on them. For paper gaskets follow the Shop Manualorque specs for the bolt being installed. Carb gaskets never get any sealant. New or totally clean spacers and totally clean carb flange and intake opening and never had any issue. There is fuel through here so most sealants are not a great choice anyway.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.

Located in Snellville, Georgia

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Re: When to use gasket sealant

Post by bbodie52 »

Click below to read some posts on his subject. I usually lubricate oil seals, the oil filter seal, and Viton o-rings with motor oil when installing them. Gaskets go on dry, while confirming flat, clean surfaces and using proper torque specs. Carburetor gaskets should include a plastic insulator spacer between them. They also go on dry.

Gasket Sealer
:link: viewtopic.php?t=13079


bbodie52 wrote:I wanted to make sure that some important insulators were not accidentally omitted when your car was worked on in the past…

Carburetor rebuild kits often contain a thin gasket to seal the underside of the carburetor where it mounts on the intake manifold. The Corvair carburetors need a plastic insulator to isolate the base of the carburetor from the intake manifold, which prevents the gasoline inside the carburetor from boiling or vaporizing if excessive heat is allowed to transfer from the hot aluminum intake manifold on the cylinder head to the carburetor body. These plastic insulators can be easily damaged when removed. Clark's Corvair Parts bundles gaskets and insulators together. They are listed near the top of page 56 in the catalog http://www.corvair.com/user-cgi/catalog ... ow_page=56.



:angry: If the insulators are not present, and only a single gasket is being used under each carburetor, the fuel may be close to boiling when the car is driven. The use of fuel may allow some effective cooling of the fluid in each float bowl as fuel is consumed and replaced with cooler liquid from the tank. But when the engine is shut down the remaining heat from the heads may continue to heat the gasoline in the float bowls of the idle engine, causing the gasoline to percolate and appear as it drips from the venturi cluster in each carburetor. :evil:
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

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