Intake/Exhaust Manifold Removal

I spent most of today removing the intake and exhaust manifolds from the engine.

Here is a shot of the intake manifold as it sits on top of the exhaust manifold. The light blue shop towels are still in place from when I removed the carburetor and stuffed them into the intake.

As shown below, the manifolds attach to the head by a combination of six bolts and washers. In the first picture, on the end toward the firewall is the bracket one can use to lift the engine out of the engine bay.

I used some PB Blaster and a 1/2″ socket to loosen the bolts.

I removed all of the bolts. The second left-most mounting point was actually a stud.

I removed the 1/2″ nut and the washer from that stud.

Then I did the same from the right-most stud, which also mounts the engine lift bracket.

Here are a couple of shots of the engine lift bracket.

I used a ratcheting wrench to loosen the inside bolts because there was no clearance to get a socket into the space.

And did the same on the other side.

The top of the manifold came loose from the engine, but the bottom was still mounted to the exhaust below. The truck came without a full exhaust system. After a brief downpipe with a resonator the exhaust terminates under the truck and never makes it to the back bumper. At first I tried to loosen the bracket that clamped the exhaust manifold to that short pipe, to no avail. So, with nothing worth saving south of the manifold, I took more drastic measures.

The exhaust pipe didn’t put up much of a fight.

So with the manifold liberated from the exhaust pipe below, I was able to extract the intake/exhaust manifold successfully.

Then I pulled that short length of exhaust pipe from the exhaust manifold.

Here are some pics of the combined manifold, still assembled.

These two pictures show the four nuts that connect the intake manifold (upper) to the exhaust manifold (lower).

This is a look down into the two intake ports below the carburetor. There is an insulator and gasket that sits on those four bolts between the manifold and carb.

Here are a couple of shots of the engine on the driver’s side. Now with the manifolds and carburetor/air cleaner stripped away it looks pretty bare.

Next I separated the intake manifold from the exhaust manifold. I used a 7/16″ box-end wrench to loosen the nuts from the four studs at the corners of the intake.

After breaking them loose I was able to turn all four off with my fingers.

With those four nuts and washers removed, I was able to pull the intake manifold up and off the exhaust manifold.

The underside of the intake manifold that mates to the exhaust manifold has a cool, accordion shape. In the picture below is is caked in black carbon from combustion. Also between the two manifolds is a hot spot gasket that thermally separates the hot exhaust manifold from the cooler intake manifold above.

Here is the free intake manifold. It appears to have originally been painted Datsun blue like the engine.

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