Egr
Moderator
Joined: Dec 2007
Posts: 7,987
Likes: 104
From: Boise, Idaho
If it's anything like my '81 (which I'm sure it is), it's pretty simple. Between the 1bbl carb and the intake is a spacer with an EGR valve on the end of it. Then, there's a pipe coming out of the exhaust manifold which routes up into the underside of the spacer.
When the engine is under load, a vacuum line pulls open the EGR valve, which lets exhaust out of the EGR pipe back into the intake.
Not a lot to it.
When the engine is under load, a vacuum line pulls open the EGR valve, which lets exhaust out of the EGR pipe back into the intake.
Not a lot to it.
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
It was earlier than that in California. Around when the EPA was formed.
My 1973 F-100 302-V8 had an EGR valve. Factory equipped.
My Father's 1976 300-I6 also had one.
But remember California was Special.
My 1973 F-100 302-V8 had an EGR valve. Factory equipped.
My Father's 1976 300-I6 also had one.
But remember California was Special.
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Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
If it's anything like my '81 (which I'm sure it is), it's pretty simple. Between the 1bbl carb and the intake is a spacer with an EGR valve on the end of it. Then, there's a pipe coming out of the exhaust manifold which routes up into the underside of the spacer.
When the engine is under load, a vacuum line pulls open the EGR valve, which lets exhaust out of the EGR pipe back into the intake.
Not a lot to it.
When the engine is under load, a vacuum line pulls open the EGR valve, which lets exhaust out of the EGR pipe back into the intake.
Not a lot to it.
You forgot the ported vacuum switch, that shuts the EGR off when the engine is cold. Hooked into the water jacket, at one of the fittings in the thermostat housing.
But agreed, not much to it in the early years.
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Joined: Sep 2008
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One more ?
I have another ? What is the small tube that runs from the manifold up to the carburetor choke? Mine has been broken off and bent over to pinch it off at the carburetor end. How do I get the other end out of the manifold?
Moderator
Joined: Dec 2007
Posts: 7,987
Likes: 104
From: Boise, Idaho
That is the heat chimney for the choke. When the manifold warms up, it sends heat up the tube and warms up and opens the choke up. It works in conjunction with the electric choke, if you have one.
You can just drill it out, it's nothing more than just a indent in the manifold and doesn't go anywhere. You can bend some more tubing and run it out of the choke and into that hole. Or, you can just have the tubing exit the choke, and then wrap it around the manifold a couple times. Just as long as it's touching.
You can just drill it out, it's nothing more than just a indent in the manifold and doesn't go anywhere. You can bend some more tubing and run it out of the choke and into that hole. Or, you can just have the tubing exit the choke, and then wrap it around the manifold a couple times. Just as long as it's touching.
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Except depending on exaust manifold, there may be a choke stove inside the exaust manifold.
Filtered air goes from the top port of the carb opened to the airhorn, goes to the bottom of the exaust manifold, goes through the choke stove in the exaust manifold, another tube is attached to the top, and this one attaches to the carb at the choke.
I would get this working, as it also helps to keep the carb from icing up, if you live in a cold climate.
You can get aftermarket choke stove tube kits at most autoparts stores.
Moderator
Joined: Dec 2007
Posts: 7,987
Likes: 104
From: Boise, Idaho
Just as AbandonedBronco described it.
Except depending on exaust manifold, there may be a choke stove inside the exaust manifold.
Filtered air goes from the top port of the carb opened to the airhorn, goes to the bottom of the exaust manifold, goes through the choke stove in the exaust manifold, another tube is attached to the top, and this one attaches to the carb at the choke.
I would get this working, as it also helps to keep the carb from icing up, if you live in a cold climate.
You can get aftermarket choke stove tube kits at most autoparts stores.
Except depending on exaust manifold, there may be a choke stove inside the exaust manifold.
Filtered air goes from the top port of the carb opened to the airhorn, goes to the bottom of the exaust manifold, goes through the choke stove in the exaust manifold, another tube is attached to the top, and this one attaches to the carb at the choke.
I would get this working, as it also helps to keep the carb from icing up, if you live in a cold climate.
You can get aftermarket choke stove tube kits at most autoparts stores.