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Discussion Starter · #1 ·
I was wondering if the heat riser on the exhaust manifold came on automatics only OR did these come on all cars regardless of trans. And if so, what side was it on?

Here is what I'm talking about:

Heat riser
 

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Discussion Starter · #3 ·
Thanks, I was wondering if it was only automatics. I am going to install my exhaust system soon and only want to do it once.
 

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DON'T DO IT!!! Even though I thought it was perfectly set up, mine did not open and I think it caused my valve seals to fry on my fresh engine. I had to wire it open, but the damage was done. Use a dremel tool to cut the flapper out to keep the correct look. Then use plugs in the intake under the carb and block off plates in the intake gaskets. Worked for me!
 

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Discussion Starter · #6 ·
Okay Kevin, I have to plug up holes under the carb on the intake? I think I know which holes you are talking about, they are the smaller holes up by the front on the carb. How do I plug them? Also, the carb takes a heat shield and a gasket right? Who sells the correct heat shield?
If you dont already know it's a 350/300hp 4spd with 184 intake and 7203 quadrajet, all original.
 

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Yep plug those ports that show in this pic of my extra intake. These are welded, but the ones on my car now were drilled and tapped then he screwed in a allen wrench type threaded plug.
Intake ports to plug
 

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I used the 7/16 steel plug recommended by JohnZ here:
http://www.camaros.net/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=9;t=009937

with the plugs you only need 1 paper gasket (no metal one!). You get a much better seal that way.

I also used the plates in the intake manifold kits and took the flapper out of the heat riser. Runs a lot better now!

It is also a 350/300, 184 intake, 7203 carb, 041 heads (which now need some exhaust valve seals, it leaks oil in #8 cyl) Hopefully I did not kill the valve guides too or it will be another head redo :(
 

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Discussion Starter · #10 ·
Wow, I just read that post by John Z - what great info!! I am kind of concerned with originality without using the metal, but then I guess I want it to run right without leaks. So basically I need to plug the holes with 7/16" plugs and put on a regular carb gasket and I'll be good to go, right??
 

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The carb seals just fine with the heat shield in place. It prevents the fuel from boiling out from heatsoak at shutdown. New heat risers can be purchased still from the dealer, $8 USD.
 

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I was just reading this post regarding heat risers. I am planning on cutting the flap out of mine because I don't think it is opening all the way and do not want to restrict the exhaust.
2 questions,
1st what is the correct position for the heat riser valve on the exhaust manifold?
2nd what is the holes Click and KevinW are talking about on the carb and why do they need to be plugged?
The photos are no longer available because of how old the post is.
 

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The heat risers job was to create enough pressure to force the hot exhaust gases back up the intake manifold, under the carb and back out the other side. this hot gases under the carb causes plate warpage and cooked gas. Under the carb are the 2 holes in the manifold that the gases would enter and exit.

An oldie but goodie thread :)
 
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