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Discussion Starter · #1 ·
I need to replace the egr valve on my 83 t-type and I was wondering if I should just make a block off plate for it or should I just go ahead and replace it, What are the pros and cons if I do this??
 

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Hydra Station Supervisor
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1,644 Posts
The big thing is it may not pass the tests in your state if you do not have a EGR valve. Also they help cool the engine since they run lean it could cause it to run hotter without the EGR I would keep the EGR valve.
 

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Carb/Turbo
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1,615 Posts
Without it you may knock while crusing down the highway. Also, it helps heat the plenum. Without plenum heat, fuel puddles under the carb and it will bog when accelerating. At WOT, EGR is disabled by the ECM.

It would be nice if the EGR didn't recirculate so much volume of exhaust gas. It overdoes it and you can feel it at part thottle. I had a Tomco unit that let you adjust the opening size, but it didn't last long (neither did the replacement).
 

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Deltona: Peace At Last...
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568 Posts
I wrote this on another forum several years ago. Take the time to read it Smiley. It may help one to understand: :sw:

Freddie's Regal said:
Detonation and the EGR's role

1) Detonation is is an erratic form of combustion. Detonation occurs when excessive heat and pressure in the combustion chamber causes the air/fuel mixture to auto-ignite. This produces multiple flame fronts within the combustion chamber instead of a single flame kernel.

When these multiple flames collide, they do so with such an explosive force that it produces a sudden rise in cylinder pressure. This results in a sharp metallic pinging or knocking noise. The hammer-like shock waves created by detonation subject the head gasket, piston, rings, spark plug and rod bearings to severe overloading.

2) The Exhaust Gas Recirculation (EGR) system leaks small amounts of exhaust into the intake manifold through an EGR valve. Though these EGR gases are hot, they actually have a cooling effect on combustion temperatures by diluting the air/fuel mixture slightly. As well as reduce formations of NOX for emissions control, this results in a smooth controlled burn that prevents detonation.

3) A lot of people think that the EGR valve is just an emissions control device and remove it. Technically it is an emissions device, but it is a needed on our cars since it allows for the higher timing.

Detonation happened to my Regal when I used the wrong EGR valve. The lesson I learned I share with this forum. Although all our EGR's look alike, they are not.

Turbo-carbed Buicks need the EGR. The high detonation caused by the lack of an EGR will ruin the engine eventually. :crazy:
 

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Good write up :yup: EGR is good exactly for that "cooling effect"

Now, which one to use on a non ECM engine?? Anyone have part numbers?
 

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Carb/Turbo
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Just FYI, I put a thermocouple in the plenum just before the compressor (where the vacuum line to the actuator was hooked up). While crusing down the highway with EGR, it will read as high as 270 F. When you go WOT, it drops to near ambient.
 
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