1973 EGR Valve

[Tom K.]

Hello All,

Im looking for help again, this time with my EGR Valve. Im gathering up parts to get the system back together correctly, right now I am trying to get the EGR Valve apart. It looks to me like the sleeve in the bottom (manifold side) will unscrew and the vacuum actuator can be removed from the cast iron mounting block. Is this true?
I have been applying PB Blaster for better than 3 weeks. I used carb cleaner and a brush to remove carbon between the sleeve and the block, a bit of heat from a Map Gas torch, some 'love taps' with a hammer - I still cant get it to turn without damaging the sleeve.

Am I just going about this the wrong way?
Maybe I need to make a tool that will fit the two notches in the end of the sleeve?

As always - thanks for any help!

[Joe L.]

Re: 1973 EGR Valve

Hello All,

Im looking for help again, this time with my EGR Valve. Im gathering up parts to get the system back together correctly, right now I am trying to get the EGR Valve apart. It looks to me like the sleeve in the bottom (manifold side) will unscrew and the vacuum actuator can be removed from the cast iron mounting block. Is this true?
I have been applying PB Blaster for better than 3 weeks. I used carb cleaner and a brush to remove carbon between the sleeve and the block, a bit of heat from a Map Gas torch, some 'love taps' with a hammer - I still cant get it to turn without damaging the sleeve.

Am I just going about this the wrong way?
Maybe I need to make a tool that will fit the two notches in the end of the sleeve?

As always - thanks for any help!

Tom------


These valves were never designed to be serviceable and no component parts were ever available. So, even if you could get it apart there are no available parts to replace any that might need to be replaced. In addition, these valves are not "forever" kind of parts. They are subject to a lot of heat and it takes its toll.

You don't mention what engine application this is for. There were 5 different valves used for 1973 depending on engine/transmission application.

[Mark E.]

Re: 1973 EGR Valve

Tom,

I recommend you clean up the exterior cosmetics as best you can, install it with a new manifold gasket, but do not connect the vacuum source. If you want it to look intact, plug the vacuum line internally then connect it to the EGR. If an original look isn't important, install a block plate on the manifold.

The purpose of EGR is to reduce NOx by reducing combustion temperature. Side effects of a disconnected EGR system is an engine that runs smoother, cooler, more efficiently and with less hesitation.... but with higher NOx out the exhaust. You may need to adjust the idle mixture.

[Tom K.]

Re: 1973 EGR Valve

Hello joe,

Thanks for the reply. this is an LS4 car with automatic transmission, A/C, PS, PB & PW. I am also wondering where to get the right gasket, or what to use to make one.


Tom

Tom------


These valves were never designed to be serviceable and no component parts were ever available. So, even if you could get it apart there are no available parts to replace any that might need to be replaced. In addition, these valves are not "forever" kind of parts. They are subject to a lot of heat and it takes its toll.

You don't mention what engine application this is for. There were 5 different valves used for 1973 depending on engine/transmission application.

[Tom K.]

Re: 1973 EGR Valve

Thanks Mark,

This (make it look right and dont worry too much about it) is probably the route I will take. Its kind of surprising to me there is so little info out there on these parts.

Tom

[Jimmy P.]

Re: 1973 EGR Valve

Tom,
I agree try to clean it up real nice. The base should be black not orange. Joe is correct… no way can you take these apart to try to repair. Does yours still function? If the rubber is still good and not dry rotted, try pushing in the bottom pin(valve) ??to see if the valve moves up and down. If it doesn’t it isn’t functional anymore. Just install it and block the hose as mentioned above. As you’ve found out these aren’t easy to find, especially if you try to find one with the correct part number/ date code/ broadcast code letters. Yours should have 7047066 with the broadcast code letters NR usually in front of the part number. With a date code underneath.
Hopefully you still have the original hold down bracket with the bolt and french lock washer, those are really tough to find for the big block as well.
As for the gasket, they are a “dime a dozen “ on ebay. Here’s an original i have NFS!

[Tom K.]

Re: 1973 EGR Valve

Thanks jimmy,

I found the gasket on EBay as you said. I just needed the part number and it came right up. The same with the valve.


Tom

[Joe L.]

Re: 1973 EGR Valve

Thanks jimmy,

I found the gasket on EBay as you said. I just needed the part number and it came right up. The same with the valve.


Tom

[Tom K.]

Re: 1973 EGR Valve

Hi Joe,

it was a used original that was in really nice condition. it was the right p/n but the wrong broadcast code. I doubt I will pursue it. I will keep an eye out for the right part.
Who knows? It may pop up


Tom

[Joe L.]

Re: 1973 EGR Valve

Hi Joe,

it was a used original that was in really nice condition. it was the right p/n but the wrong broadcast code. I doubt I will pursue it. I will keep an eye out for the right part.
Who knows? It may pop up


Tom

Tom------


I'd be very leery of any used EGR valve. As I mentioned, these things are very life-limited components. So, it'd be like buying used spark plugs. Even if it's functional, for how much longer?

I do not understand why the part number would be right and the broadcast code wrong, though. The broadcast code is usually specific and exclusive to a part number.

[Tom K.]

Re: 1973 EGR Valve

Joe,
I just went back to Ebay and both the p/n and broadcast code were different.

Tom

[Tom K.]

Re: 1973 EGR Valve

Hello All,

I did get the EGR finished up. It ended up just cleaning and painting. I also got (2) NOS EGR gaskets for pretty cheap on Ebay - If someone needs one let me know. I was able to mill out (3) tiny stakes in the threads of the sleeve I mentioned above (see picture below of the bottom surface of the valve) and thread out the sleeve. However, all that really did was mess up the sleeve and the actuator STILL will not come off. The sleeve is basically a seat for the actuator stem and that it. I do not see how they assembled the actuator to the base. Anyway, I made a new sleeve from a 3/4-16 threaded bolt and glass beaded the entire assembly. It looks much better, but being the stubborn type I may pursue this further with an EGR valve Im willing to sacrifice.
Here are a few pix - as always thanks for your insights.


Tom Krause

[Jimmy P.]

Re: 1973 EGR Valve

Very nice work Tom. It turned out really well as compared to what it looked like above.
Just a suggestion though… the hold down bracket should be black not engine orange if you want it to look original. I guess it was
originally called “black oxide”as per the correct part finish aficionados….not really painted. I just call it flat or satin black!

[Mark E.]

Re: 1973 EGR Valve

If you're going to install this valve for cosmetic reasons instead of using a block-off plate, make sure it's stuck in the closed position to prevent exhaust from getting into the intake. To clean up the finish, soak it in EvapoRust then wipe with WD-40 or other light oil. This should improve appearance.

[Tom K.]

Re: 1973 EGR Valve


thank You Jimmy, I was wondering what was correct. I will be starting anew thread shortly as I have ost of the parts for my intake together and I was hoping for some info on just these kinds of questions.


Tom