Intake/Exhaust Manifold
 

I acquired a Exhaust Manifold without any Pits on it, best I have ever found, the Intake had a carb mounting ear broken off, so I'm using another Intake. While I have them split, I sandblasted them, the Exhaust I sprayed with Eastwood Stainless Exhaust Coating and Ford Model A Green for the Intake.

My Question is, before I Mount them together, should the Flat Mounting Surfaces of both be Free of Paint and just Bare Metal ??
I believe the Exhaust pre-heats the Intake, and would be better if left Bare metal to metal. Have searched for an answer, but have come up empty handed.
After I bolt it together, I will have it Planed

Re: Intake/Exhaust Manifold
 

I am guessing that both surfaces (if the exh. manifold was even painted) were painted from the factory for speed sake. I would just paint them both for three reasons:
1) nobody will see them
2) protect from rust
3) heat transfer won't matter much with paint being in the way.

Mike

Re: Intake/Exhaust Manifold
 

I agree. I wouldn't worry about the thin coat of paint, and the intake will still get plenty of preheat.

I always use the copper gasket for the manifolds and carb to intake.

Re: Intake/Exhaust Manifold
 

For a little while I had an xhaust manifold that had been cut a an angle, there was a 1/4 gap between the manifolds, the car ran about the same, it was on the car for the fourth ofjuly parade, I was curious to see if the cold intake manifold would change any heat induced mixture problems ---the previous manifold had a big crack that directed exhaust gas directly on the carb bowl ---the car ran the same, it also had an exhaust leak, the manifold was at such an ange that the muffler couldn't seal.

I had been thinking that some space (less heat transfer) could help with what is called "vapor lock" --I put on 50-75 miles,car ran the same, but was tired of having an exhaust leak so I went to my brothers and stole a different manifold ---now I have quiet, the 2 manifolds are touching, the car runs the same

Re: Intake/Exhaust Manifold
 

If you are mating up two orphan manifolds it is recommended that you lay a straight edge along the surfaces of both manifolds bolted together to see if they are even with each other. Quite often the manifolds in the past have had the mounting surfaces machined flat. You could easily end up with a gap between the engine block and one of the manifolds.

Tom Endy

Re: Intake/Exhaust Manifold
 

Tom, I inserted 4, 1/2 bolts where the Manifold Studs would be, thus aligning the Mounting Holes Center. Ran a Bottom Tap in the Threads, used air to blow them clean. Than I put Red Lock-tight sealer on the 2, 7/16 x 3/4 x 18NC bolts w/ lock washers that hold the Manifolds together, and tighten them up real tight. The 7/16 bolts are New Grade 8.

As I mentioned above, it is going to be Surfaced at the Machine Shop. I did take a Machinist Straight Edge I have, placed it on the holes, Both ends I could slide a .005 Feeler gauge under the inside edge, the others were pretty flat. This Exhaust Manifold has the Reinforcing hump on the Outlet Elbow. I do not think these manifolds have ever been machined.

Re: Intake/Exhaust Manifold
 

Tom, I find that using the copper clad gaskets between carb and manifold are a good way to break carb ears on iron carbs and warp the pot metal ones. I advocate using a mill file and very thin gaskets with a super thin coat of sealer.