to gasket or not to gasket, that is the question

[WarMonger]

I have heard some people run gaskets and others don't? I was thinking of using gaskets. I cleaned and decked both surfaces. What do you guys think/recommend or have heard of?

[Taibo]

Originally Posted by WarMonger

I have heard some people run gaskets and others don't? I was thinking of using gaskets. I cleaned and decked both surfaces. What do you guys think/recommend or have heard of?

I would run a gasket with those. You still have low spots on the center ports but a gasket will make up that difference easier than continuing on with decking that header. Soft copper works really well on Iron manifolds bolted to iron heads. 32 Ounce (.050) sheet is available on the net in 12 x 12 pieces. Cut six rectangles slightly larger than each port, scribe and drill the holes and bolt them to the port. Use a ball peen hammer to tap around the edges of the perimeter and the center. The sharp harder edge of the manifold will cut the pieces out perfectly.

Now comes the part your wife is really going to love. Set your oven to 350 degrees, get a baking dish and put 1/2 inch of sand in the bottom. Put the copper gaskets on top, cover them with another 1/2 inch of sand and bake them for two hours. Turn the oven off and let it cool back to room temperature before opening the door. Your gaskets are now annealed and will be very soft. Soft enough to compress when the manifold is torqued down. Just remember, if you ever need to loosen those bolts, you will need a new set of gaskets.

[Fldawg]

i've always used gaskets, some of the new gaskets really do a good job, i've never heard of not using gaskets, and i've been a mechanic for over 27 years now

[jocko]

Yes. I run the perforated metal type.

[picklito]

I always use a gasket. And I like the metal-sandwich version on both headers and cast manifolds. Gaskets dry, anti-seize on the bolts.

[WarMonger]

Originally Posted by Taibo

I would run a gasket with those. You still have low spots on the center ports but a gasket will make up that difference easier than continuing on with decking that header. Soft copper works really well on Iron manifolds bolted to iron heads. 32 Ounce (.050) sheet is available on the net in 12 x 12 pieces. Cut six rectangles slightly larger than each port, scribe and drill the holes and bolt them to the port. Use a ball peen hammer to tap around the edges of the perimeter and the center. The sharp harder edge of the manifold will cut the pieces out perfectly.

Now comes the part your wife is really going to love. Set your oven to 350 degrees, get a baking dish and put 1/2 inch of sand in the bottom. Put the copper gaskets on top, cover them with another 1/2 inch of sand and bake them for two hours. Turn the oven off and let it cool back to room temperature before opening the door. Your gaskets are now annealed and will be very soft. Soft enough to compress when the manifold is torqued down. Just remember, if you ever need to loosen those bolts, you will need a new set of gaskets.

This pic shows the low spot, but I have everything flush now. Thanks for all the advice. I'm gonna go with gaskets. I spent all weekend sanding surfaces down. I even made a phonelic plate for the carb

[Bigdav160]

i've never heard of not using gaskets, and i've been a mechanic for over 27 years now

GM quit using gaskets there in the early 1980's

[BB72CHEVKT]

I run the manifolds with no gaskets and no leaks.

[Taibo]

Originally Posted by Fldawg

i've always used gaskets, some of the new gaskets really do a good job, i've never heard of not using gaskets, and i've been a mechanic for over 27 years now

Sanderson uses a 1/8 in wide by 1/16 in high sealing ring machined into the aluminum header flange on their headers. No gaskets. If you use locking fasteners, or just keep the bolts properly torqued they will never leak.

[leftybass209]

No gaskets from the factory. If they were decked correctly, and verified flat with a level, they'll be fine without gaskets. I have a good number of miles on mine, leak free. Best of luck with your decision.

[hamjet]

Originally Posted by WarMonger

This pic shows the low spot, but I have everything flush now. Thanks for all the advice. I'm gonna go with gaskets. I spent all weekend sanding surfaces down. I even made a phonelic plate for the carb

Where did you get the phonelic material to make your own?

[indymachinist]

Absolutely use gaskets.

[GRX]

Unless you have two flat surfaces, which you don't from looking at the first image. Use gaskets.

[WarMonger]

Originally Posted by hamjet

Where did you get the phonelic material to make your own?

Lets just say it fell off a truck about 7 years ago.

[WarMonger]

Originally Posted by GRX

Unless you have two flat surfaces, which you don't from looking at the first image. Use gaskets.

I do have 2 perfectly decked surfaces. the pic is just in the middle of the process. That's why I'm asking if to use gaskets or not.

[Aruba1]

Originally Posted by WarMonger

I spent all weekend sanding surfaces down.

How did you deck the surfaces? Use gasket, I have never removed a manifold that did not have a gasket.

[geezer#99]

If you're trying to keep heat away from your carb, you need a heat shield instead of a spacer.
Especially with a holley.
https://www.holley.com/products/fuel...s/parts/108-70

[GRX]

Originally Posted by WarMonger

I do have 2 perfectly decked surfaces. the pic is just in the middle of the process. That's why I'm asking if to use gaskets or not.

So all the surfaces were checked and confirmed flat (with each other) with a good straight edge?

[WarMonger]

Originally Posted by geezer#99

If you're trying to keep heat away from your carb, you need a heat shield instead of a spacer.
Especially with a holley.
https://www.holley.com/products/fuel...s/parts/108-70

A phenolic plate is an absolute heat shield.

[WarMonger]

Originally Posted by GRX

So all the surfaces were checked and confirmed flat (with each other) with a good straight edge?

Yup, I have a machined straight edge and a machined 2 foot sanding bar. all surfaces are flat with each other. Took me 4 hours to do the block and headers. It was not fun.

[GRX]

Originally Posted by WarMonger

Yup, I have a machined straight edge and a machined 2 foot sanding bar. all surfaces are flat with each other. Took me 4 hours to do the block and headers. It was not fun.

Cool deal. Was just asking since I have seen a lot of sbc heads blown out at the gasket surfaces from them just being sanded smooth with a disk.

[geezer#99]

Originally Posted by WarMonger

A phenolic plate is an absolute heat shield.

Yup!!
For a carb that has the fuel bowls directly above the plenum.
A holley needs a shield under the bowls.

[Keith Seymore]

Originally Posted by WarMonger

A phenolic plate is an absolute heat barrier.

...for a structure borne heat transmssion path.

You also need the shield for convection (air borne heat path).

K

[cleszkie]

I respect the effort that went into "decking" the heads and manifolds. However, dropping in a good set of soft aluminum gaskets would give you the same result without all the elbow grease. I did that many years ago and never looked back. The aluminum gaskets are also reusable if you have to pull a manifold. BTW, have you fired the engine without gaskets to check the decking job? That should answer your question.

[Taibo]

Originally Posted by WarMonger

Lets just say it fell off a truck about 7 years ago.

Isn't it amazing how lots of useful stuff seems to fall off trucks.....