73 340 emissions questions

[GOLDMYN]

Hi, my 73 Duster has all the original emissions equipment still connected, Can I disconnect any of it and expect the engine to run decent? I'm sure the charcoal cannister is dirty and although I've looked at the EGR valves in the manifold and they look OK, I'm not sure if they are working properly, since none of these items can be bought over the counter, its certaily easier to just disconnect if possible, your opinions please....Thanks

 

[phwx2]

I don't know squat about the charcoal cannister but I wouldn't disconnect the EGR if your drive it on the road and want to tune if for road driving. What the EGR does is put some exhaust into the intake at light throttle. It slows down the burn. So you can have alot of advance in the the vacum advance timing. Correct initial timing, mechanical timing and vacum advance will give your car better fuel economy without knocking. As far as performance the ERG, is acitivate by high vacum. To test it just rev the engine and when the vacum goes down, ie peddle down, the EGR valve should be closed and when the vacum is high ie when you let off the gas, the EGR should open. I've used junk yard egr valves. They are hard to kill. The passages do clog up with crap and you can remove the valve and then dig out the carbon and crap to make it work. In a sentance the egr help stop fatal pinging due the an agressive vacum advance. An aggressive vacum advance help get decent milage. If its a 1/4 mile car its irrelevant. If its a street car keep it and make it work with a correct tune. Hope this helps. Sorry no one answered before this.

 

[GOLDMYN]

thanks for replying, is it as simple as unscrewing the EGR while the manifold is on the car and then cleaning them?, I've looked at them and they look ok, and are they fragile?, this car does run ok,and I don't want to break anything. but I'm having the carb rebuilt and while everything is off I want the insure its running at its best.

 

[phwx2]

These are pretty rugged pieces. I remember cleaning out the EGR passages on my 318 back when I was 16 yrs old and prone to breaking things. I didn't take the intake off. But you do want to make sure none of the chunks of crap (assuming yours are not clean) don't go into the engine. If you've go the carb off it may be easier. I have probably done it to 5 slant six engines. Simple as unscrewing - well I can't recall breaking a screw but I've broken so many screws in my life one or more may have been on an EGR. I can't garuantee you won't break something. Since your carb is off you could test the egr with outside hand vacum pump - or even hook it to a vacum line on another car thats running.

 

[GOLDMYN]

Hi, after searching, I find that the 73 340 has NO EGR valve, it was exempt and carried over the 72 design which only had "floor jets" in the intake. The rest of the engine line-up did have the EGR....lucky me.

 

[rumblefish360]

Gold, you are a bit lucky in that you didn't have to search for a EGR gasket. There hard to find very high temp gaskets. The floor jets can be cleaned out.

The charcoal canister helps not only in emissions, but will help with vapor lock. It's suposed to. That and vapors from the carb. It's not a HP robbing item.

I beileve you have the vacuum advance line for the carb going to a black plastic part located on the passenger side fire wall. This part, I forget the name, is designed to delay the advance of the distributor. By pass it and simply run the vacuum lines togther. By way of a T fitting to connect the lines or a new line.

You can leave the equipment on and just add performance items without ill effect. The best and most simple upgrade would be an ignition box. I suggest ethier a MoPar Chrome box with it's proper ballast resister or a MSD which will help more so down low in the RPM band with power and mileage.