Stock Intake Manifold Question

[JT]

Am restoring my 75 and wanted to keep the engine as stock as possible.

When removing the gaskets I had to clean a bunch of carbon out of the two small middle ports. On one port, the carbon plugged a passage that led to the inside of whatever this sheet metal piece is covering. The sheet metal piece needs to come off so I can clean the inside of the manifold. It's held on by rivets, how do I get this piece off?

JT

 

[ryansbronco]

grind the heads off then pry up the baffle
there should be some stud that you can get a vice grip on
then use a 1/4 20 tap to make new hole
use red lock-tight to make sure they don't back out down the raod

 

[broncnaz]

I wouldnt even bother removing it. Just spray degreaser in there or use oven cleaner and hose it off all that oil/sludge will come off.

 

[broncodriver99]

The exhaust crossover is under there. It is cast into the manifold though. The only thing under that cover is a pipe plug which will give you access to the crossover passage. They are just blind rivets with somewhat of a twist to them to get them to bite. You could try unscrewing them with vice grips or cutting a slot in the head and using a big screwdriver. You can carefully pry them out too.

 

[Broncobowsher]

See that small port between the intake runners on both sides? Down and right of where your finger is pointing. That port is connected side to side on the intake. It is also where the carboned port at the carburetor goes to. It connects to the exhaust runners and is the carb heat and EGR supply. The carboned ports at the carburetor are the EGR ports as well.

That sheetmetal cover doesn't cover anything that you need to worry about. It is simply a splash shield to keep oil from burning up from the exhaust heat of that runner. If you really want to remove it you have to cut the rivet heads off then drill and tap the manifold for bolts to replace the rivets. Most aftermarket manifolds don't even have that sheetmetal cover.

 

[72Sport]

I have removed of the heat shield rivets with a sharp wood chisel. It has been a while but I believe I drove the smooth side of the chisel between the manifold and the shield under the head of the rivet. After you get the rivet loosened You can clamp a pair of vise grips and twist it out the rest of the way.

I tapped the tow holes with a 1/4-20 tap. I don't think I drilled it. The rivet holes were very close to the tap drill for a 1/4-20.. If you use hex head bolts to hold the shield on you can bend of the shield on two sides of the bolt head so they don't loosen up while you drive.

Here is a picture of a aluminum manifold. I have done the same with cast iron manifolds.

 

[JT]

Thanks for the responses.

So if while chipping the carbon out of the port and a piece of it made its way down there, just removing the rivets and the cover wouldn't necessarily give me the access I would meet to clean it out?

 

[Broncobowsher]

No. That cover is just a splash shield. Does not go to the ports.

 

[broncodriver99]

Thanks for the responses.

So if while chipping the carbon out of the port and a piece of it made its way down there, just removing the rivets and the cover wouldn't necessarily give me the access I would meet to clean it out?

Just gives you access to a pipe plug. Once you remove the pipe plug you will have access to the chamber.

 

[broncodriver99]

This is what is under there. This is a stock 4bbl intake, but should be the same.

 

[JT]

So if I remove the splash shield and then unscrew the plug I should be able to get out anything that may be trapped in there?

 

[72Sport]

So if I remove the splash shield and then unscrew the plug I should be able to get out anything that may be trapped in there?

My guess is you would strip the hex out of the plug long before it came loose. It probably need to be drilled out and re-tapped. If it is just small pieces of rust dropped in the egr ports blow it out with compressed air. Run a piece of wire though the ports. Flush it with water and blow it dry with compressed air. Leave the plug alone is my suggestion.

 

[broncnaz]

X2 the crossover ports connect to each other blow it all out with compressed air. Any chips inside will come out. Once you have as much ogf the big stuff chipped out spray some oven cleaner in the ports it wroks pretty good at getting carbon loosened up.

 

[JT]

Thanks guys. I'm mot going to mess with it.