Exhaust manifold gasket

[KennyCuda]

My mechanic who's been a mechanic for like 40 years and a big mopar guy told me when i install my exhaust manifolds not to use a gasket he said the factory made and the heads milled the manifold to bolt the head with no gasket. Im kinda afraid not to use a gasket. Your thoughts

 

[Chryco Psycho]

He is Correct , I use a thin layer of ultra copper silicone , if you use a gasket it will fail quickly

 

[toolmanmike]

My mechanic who's been a mechanic for like 40 years and a big mopar guy told me when i install my exhaust manifolds not to use a gasket he said the factory made and the heads milled the manifold to bolt the head with no gasket. Im kinda afraid not to use a gasket. Your thoughts

Small blocks used steel shim gaskets with heat shields for the plug wires on the driver's side.

 

[Steve340]

As Chryco has mentioned.

You can use high temp silicone with no gasket provided the heads and manifolds are cast iron, and the surfaces are in good condition. Everything must be clean and not oily.
A trial fit is usually a good idea to check out fasteners/fit etc.
Some care must be taken when fitting the manifolds and allow some cure time.

 

[KennyCuda]

Ok thanks for the info ill use the silicone. I have the original heat shield for the passenger side. Should I put silicone on the heat shield also? or isn't that necessary?

 

[KennyCuda]

I just ordered permatex ultra copper silicone from amazon 3oz

 

[Steve340]

I would use a smear on that gasket if it is sealing exhaust.
It make the gaskets come off cleanly also. I coat the flange gaskets these days as well.
Getting that baked on gasket material off manifolds/pipes is a pain in the ass.

 

[KennyCuda]

Ok thanks

 

[DaveBob]

My mechanic who's been a mechanic for like 40 years and a big mopar guy told me when i install my exhaust manifolds not to use a gasket he said the factory made and the heads milled the manifold to bolt the head with no gasket. Im kinda afraid not to use a gasket. Your thoughts

I had about 150,000 leak-free miles without gaskets or silicone. The trick is to "stone" the surfaces on the head and the manifold first. Use a knife sharpening stone on each interface until you see bare metal spots at the top, bottom, left and right. Wipe the surfaces with a clean cloth and residue free solvent, like MEK, acetone or brake cleaner. You will not need to or be able to get the entire surface down to bare metal. You just need to hit all the high spots all the way around. I prefer a medium grit stone, 1/4" thick, 1" wide and 4" long. I carried one in the machine shop in the 70's and 80's to remove any burrs or high spots on fixtures or machine tables before mounting fixtures on the machine. I put about 250,000 miles on my 69 340 Dart over a 20 year period. I discovered the no gasket trick about half way through the quarter of a million miles. I also used the trick on my 70 340 Cuda and my 74 Power Wagon, but only put about 25,000 miles on the two after removing the gaskets. On each vehicle, after installing the manifolds without gaskets, I torqued the manifolds to spec, in the proper sequence. I repeated the torque after the engine had been up to temperature a few times. I don't know if the retorque was necessary, but it didn't hurt.

 

[KennyCuda]

Thanks for that info where can I purchase one of those stones

 

[DaveBob]

Thanks for that info where can I purchase one of those stones

I bought the last stones at a local machine shop supply. Previously, I bought things there like cutting fluid, taps, thread inserts, and layout dye. Also, check out McMaster-Carr's website at mcmaster.com. However, you may want to get enough things to make shipping worthwhile. They can estimate shipping, or at least they do when I phone in my order. They take online orders, too. You may find more stuff that you want, since they keep over a half a million items in stock and get them to you promptly. Where I live, I get things the next day. They are a great source for all manner of things, from nuts, bolts, washers, grommets, drills, taps, dies, reamers, sockets, cutoff wheels, metal and plastic raw stock, to the parts cabinets and drill cabinets in my garage.

I use the stones for gasket prep. After thoroughly scraping the surface, I stone it to remove the high spots. I buy two or three stones at a time. They do tend to wear or get damaged. I clean them with aerosol brake cleaner. Be careful with aluminum surfaces, as they tend to clog the stones.

 

[KennyCuda]

Great Thanks ill check them out