I apologize for the redundancy of my topics...

Is the EGR valve really neccesary on my '73 390? Durn thing looked like it's never been cleaned, and the last few letters/numbers are missing off it, so I haven't been able to find a match for it yet. If it's just an emmissions thing, I really don't care. If it's needed for the motor to run properly, then I need to find a replacement.

Or could I just put a spacer plate under the carb and plug off it's vacuum outlet on the intake? I don't think it was hooked up right anyway, and my book doesn't tell what all it's supposed to hook to.

 

EGR (Exhaust Gas Recirculating) valve is an emissions add on to lower one of the gases the EPA is hung up on. I always pull them, make a plate for them in non-emission test areas and block it off. In test areas, I put the plate between two gaskets to block it off, but put the EGR on top so it looks like it is still functional, but isn't.

 

Josh, I think the EGR sytem was put there for a purpose and if you have all the components you should keep it because of the value it has:

https://www.ford-trucks.com/forums/1...m-routing.html

http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW

http://bbb-carb.com/std/egrvalves.htm

Best
Wishes

 

I don't have all the components... just the valve, carb plate, and one vacuum hose that, when I pulled it off it's vacuum outlet on the intake, was plugged.

 

Could you do me a favor and direct me to what you want me to see there?
(I'm too lazy to figure it out)

The EGR is for NOx reduction.
The EGR kills your low end power.
Dead.

Alvin in AZ

 

http://www.tomco-inc.com/Catalog/15egr%20valves1.pdf

Well, Al Gore has been doing study on something.

 

The EGR valve was put there to lower your performance and gas mileage as a Governmnet inspired stupidity. So plug it and have your motor run better and get better gas mileage. Do you really thing it is a good idea to introduce exhaust gas into you intake system? Sounds stupid to me.

Use a block off plate and then run the vacuum line to manifold vacuum as it won't matter then.

 

Interesting explanation there Bear. Wrong, but at least it's concise.

The EGR system is there to control the emissions of Nitrogen Oxides (NOx). It is not necessary to keep the engine running and the engine can be tuned to run without it. If you have to pass an emissions inspection then yes, it is necessary.

Every internal combustion engine can emit NOx (not the go-fast laughing gas), no matter what fuel it burns (even pure Hydrogen). This is because they all get their oxygen from the atmosphere and the atmosphere has more N2 than O2. NOx is formed when the temperature and pressure inside the combustion chamber is high enough. It also turns out that higher combustion chamber temps and pressures are seen as increased performance -- higher combustion pressure pushes on the pistion harder and is seen as more torque and power. The EGR system introduces controlled amounts of unburnable (inert) exhaust gases to the intake stream. This gas takes up volume in the combustion chamber and causes there to be a smaller fire in the chamber. The smaller fire creates a lower temperature and reduces the formation of NOx. The lower temp also is seen as lower performance.

There have been several flavors of EGR. I wasn't aware of any 390 with an EGR system. But with CA emissions, I believe it's possible. The EGR systems I've seen so far are on 360 engines with 2bbl carbs. There is an EGR valve on a spacer. Ford also had an EGR system without a valve. It was simply a 4 bbl spacer with a passage that constantly routed exhaust gas to the primaries. Saw that on a 75. There was also a 4 bbl spacer that blocked off the EGR function. Thankfully, that's the one on my truck.

 

ty Bear, food for thought. So it seems that the EPA or whoever decided on emisson testing were just retarding the output of the deadly emmision by taking up space, would someone get those guys outta there, lol.

 

Thanks for the insightful post there, William...

On that note, what vacuum stuff do I really *need* on my 390? Just the PCV and timing advance?

 

And if you had read the whole thread you would have seen where in an earlier post I said it was a government inspired emissions thing to lower one of the contaminents they paniced about. But it real end result was a lowering of engine effeciency which lowered drivablity and fuel economy. So see I do know what I'm talking about, but then the issue was to get rid of the stupid thing or not.

 

You got it right, the rest is to cost you money and to make your motor run worse or to cover up the worse running.

 

Indeed, and I truly appreciate the advice. The less I have to replace/repair on this engine, the better on my severely limited funds.

The PCV system only has the PCV valve and line... the oil filler cap is a flat cap, so I am going to find a filtered oil breather cap to fix that problem so I have proper air flow through the crankcase, and I'll make an aluminum plate to block off the back of the EGR spacer block. Would I absolutely need a gasket with that? I also fabricated an aluminum control arm to convert the automatic heat-controlled choke to manual, since I don't want a butt-ugly tube running to my exhaust manifolds, which are soon to be replaced by headers anyway.

Unless the EPA dude has something negative to say about headers too...
(It's a joke, son, you can laugh now)

 

There are hot exhaust gas flowing thru the crossover where the EGR picks up the gas, so a gasket is a good idea. Rather than go with a manual choke, you can find an electric choke heater and install that in place of the exhaust heated cap, then you still retain the automatic choke, I'm getting lazy in my old age.

 

76supercab2, thanks for the very technical explanation of the EGR and it's function.

Let's not make this like the other thread about vacuum advance

A few things I have to mention in relation to the EGR, basically some things I have learned from working on it, and anyone can figure out just by looking at the darn thing and where it's plugged into.

1) The EGR is meant to open on light-to-moderate loads. This, I'm assuming, was done with ported vacuum from the carb.

2) At WOT (wide-open-throttle), the EGR should NOT BE OPEN AT ALL. (however, do remember Dinosaur's lecture on ported-vacuum pulling vacuum at high RPM/WOT - this could be one place where this really comes into play and causes high-end/WOT performance problems when you have an EGR on the motor).

3) The official intent of the EGR is to "reduce combustion temperatures to limit the formation of NOx (oxides of Nitrogen)".

4) All things being the same, a motor with a malfunctioning EGR is prone to pinging. If your originally-equipped-with-an-EGR motor is pinging and you can't figure out why, check the EGR. Likewise, if your carb is for an EGR motor and you've removed it, you probably need a re-tune for moderate-load operation. The extra exhaust gas in the intake charge limits the peak combustion temperature. It also slightly leans out the mixture, because there is a small amount of O2 in the exhaust gas (when running correctly).

5) What the effects of the EGR were in the 70's in terms of performance, I have no idea. My '74 highboy came without an EGR. My 2001 V10 doesn't have one either, that's a seperate story later on.

6) I've seen 80's and maybe late-70's cars/trucks setup to not enable the EGR until the engine was warm enough. This was done with a PVTS(?) - ported-vacuum-temperature-switch? Can't remember the acronym someone used here just recently. My '96 and '97 EFI cars (4.6L) don't hit the EGR until they reach a certain temp (verified with my Autotap), don't remember what though. (Had an annoying stumble on my '96 t-bird 4.6L when just barely touching the pedal. Never figured it out until one day... I was watching the "duty cycle" on the EGR valve with an Autotap - I noticed it opened at very slightly off-idle, very small throttle opening. So, I put a restrictor in the vacuum line to the EGR, about .010" and that slowed down the reaction of the EGR enough to kill the stumble. )

7) EGR and the resulting NOx reduction is still a big thing federally, and especially in CA-emissions "green" states like NY. EGR has been added to diesels in the last few years (Ford's 6.0) and has made it's way into the heavy-duty truck-engine arena. My 2001 V10 doesn't have it. Later 2-valve V10s do, maybe only California. The 3-valve V10's ('05-up) limited availability in 2007 for "green" states is most likely because it doesn't have an EGR. In 2007, CA emissions requires EGR on trucks up to 10,000lbs. The only V10 in 2007 in CA was in the F350 10K+ GVWR

OK, pointless history.

Disclaimer: Any mistakes are typos and are certainly not because of loss of memory or plain stupidity. Please refer to the section # if (when) picking on me