What is it for and can it be blocked off????

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Old May 12, 2007 | 06:31 PM
  #1  
LadySkye1080's Avatar
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From: Colorado
Question What is it for and can it be blocked off????

I have a 1980 Olds. Cutlas, with a small block 260 V8. I am rebuilding it and have come accross 2 openings one on each of the heads that go into the exhaust. One is right next to the EGR and the other is directly accross from it. There are no bolts holes and there is no way for a gasket to cover them. When air is put through them, the air comes out the exhaust on the heads. So far no one has ben able to tell me what they are for or do. I don't know if they are part of the emissions system since the book doesn't show them. They look like an upside down u that has ben slightly streched and you can see down into the pistons. Back in Feb. it caught on fire, we were able to put that out, but since it was at night and I didn't get to see the damage for a few days I am not sure if I lost more then just a few hoses.

If anyone can help please let me know. I really don't want to end up taking it apart again. (Sorry for bad spelling, I am frided over this)

Thank You,
Lady Skye
Old May 12, 2007 | 08:23 PM
  #2  
joe_padavano's Avatar
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Joined: Mar 2007
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From: Northern VA
Originally Posted by LadySkye1080
I have a 1980 Olds. Cutlas, with a small block 260 V8. I am rebuilding it and have come accross 2 openings one on each of the heads that go into the exhaust. One is right next to the EGR and the other is directly accross from it. There are no bolts holes and there is no way for a gasket to cover them. When air is put through them, the air comes out the exhaust on the heads. So far no one has ben able to tell me what they are for or do. I don't know if they are part of the emissions system since the book doesn't show them. They look like an upside down u that has ben slightly streched and you can see down into the pistons. Back in Feb. it caught on fire, we were able to put that out, but since it was at night and I didn't get to see the damage for a few days I am not sure if I lost more then just a few hoses.

If anyone can help please let me know. I really don't want to end up taking it apart again. (Sorry for bad spelling, I am frided over this)

Thank You,
Lady Skye
Are you talking about the ports on the INTAKE side of the head? If so, these are the exhaust crossover passages that seal to the crossover on the intake that runs beneath the carb. The purpose of this passage is to improve fuel atomization when the engine is cold by running the exhaust under the carb and out the other side. There should be a thermostatic or vacuum operated flapper valve on the outlet of the driver's side exhaust manifold. When the engine is cold, this flapper closes and exhaust from that side of the engine is redirected through the crossover under the carb and out the passenger side manifold. As the engine warms up, this flapper opens and the exhaust passes out the manifolds normally.

These passageways do disturb the exhaust flow a little. On high performance motors these ports are filled using melted aluminum that is cast in place. Once cooled, the aluminum is ported to match the rest of the exhaust ports. Of course, blocking the crossover results in rough running in cold climates until the engine warms up.

I doubt a 260 will ever be a high performance motor, so just leave them alone.
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