Egr Valve Or No Egr Valve

Just as the title says I've finally gotten my jeep going and I'm not exactly sure where to plug in the EGR valve? Also I'm curious if I can just do away with it?

 

What engine do you have?
-Donny

 

Your EGR valve needs to be closed at idle, so it typically connects to ported vacuum. There also should be a thermostatic valve between the carburetro vacuum port and the valve that only opens the EGR when the temperature is up. If you open the EGR when the engine is cold, the it will hesitate and perhaps stall on acceleration.

The EGR adds exhaust gas to the charge, basically reducing the oxygen concentration. The idea is to reduce the combustion temperature and thereby reduce the amount of NOx in the exhaust. If you remove the EGR, you will have more oxygen, and the engine will run a little lean. Maybe not a problem; hard to predict.

 

I blocked mine off on my 231 when I put it in. I did not run the engine prior to the rebuild and installation in the JEEP so, I can offer no before/after comparison in performance and drivability.

 

I, personally, think the EGR is worthless.

 

It does reduce NOx emissions. That's its purpose. Aside from that, it's worthless.

 

Worthless failure prone component. Block it off.

 

Wasn't there original use/design to prolong the life of the catalytic converter?

 

I don't think so. EGR came before the wide-spread use of catalytic convertors.

Are you thinking of air injection? Some catalytic convertors need an air supply from the air injection pump to function. Modern convertor designs eliminate the fresh air supply, and can function using just the residual O2 in the exhaust. Air injection came before catalytic convertors, and was able to reduce CO and HC without addition of a catalyst.

 

I believe your right.

 

Forgo buying a new car and drive/repair your older rig. This will do more for the environment than anything you can do to your car by orders of magnitude.

This site, helping others put more miles on older rigs and offsetting new car production, is actually a VERY real world productive environmentally friendly site. Thanks to you all for your help

 

It's all about finding a happy medium in my opinion. I want clean air but I also want a vehicle that's simple and reliable. Having a charcoal canister and egr valve, even a cat doesn't bother me but forget air injection pumps, thermostatic air inlets, the junk modern diesels have, etc.

 

Each state has their own laws about emissions compliance. This is just like the situation with legal pot, I believe. The state chooses to enforce the Federal law, or not. Owning/buying/growing pot is still illegal everywhere in the USA... as is removing/disabling emissions devices. Your local FBI or Federal Marshals (or EPA police - don't laugh - not so far fetched: Massachusetts Environmental Police ) or whatever could choose to enforce the law ... currently they do not. Not a comment on the morality of the law, just the legality involved.

I would not fault someone for following their conscience, thereby deleting specific devices that can no longer be maintained. But - IMO - there is almost always a way to keep all these devices functional, or replace/upgrade to maintain or improve emissions performance.

However - [ ...DELETED...] vapor recovery, which has negligible negative characteristics while providing significant benefits. That includes the thermostatic air inlet - which works with vapor recovery to recover float bowl vapors while the vehicle is not running. It also provides better and faster engine warm-up, and prevents carburetor icing under cold, damp conditions. Remove if you enjoy your garage smelling like gasoline. Considering the advantages, not much of a burden, IMO.

Note you would not need a lot of these devices if the vehicle did not have a carburetor. No more float bowl. Better fuel control - you would not need air injection because the mixture no longer goes rich on deceleration. You'd likely still need EGR, but I expect the performance of EFI plus EGR would be well ahead of your factory carburetor with no EGR.

 

Huh. I was more responding to dane71's post and mention the TAC (thermostatic air cleaner) as an example of how removal of emissions devices can eliminate some engine function that reasonably the owner may want to retain. I see which post is gone ...

Does the OP have a 231 in his CJ? I recall that the 225 supplied as OE in the CJ through '71 does not have an EGR system. (Pretty sure 73-CA V8s were the first Jeeps to get EGR). The later 231s used by Buick in the passenger cars did have an EGR valve. Removing the EGR affects the fuel-oxygen ratio of the mixture. Its function is to replace some of the incoming air with exhaust gas, which is oxygen depleted. This reduces the charge density of the incoming mixture, and this dilution with inert gas (O2-depleted exhaust) reduces the peak temperature of combustion. Combustion of atmospheric nitrogen at high temperatures is what makes the nasty oxides of nitrogen (NOx) in automobile exhaust. There is quite a high energy barrier to the combustion of nitrogen, and reducing combustion chamber temperatures by dilution (adding inert exhaust gas) significantly reduces the NOx byproducts in auto exhaust. NOx is what makes the brown haze in photochemical smog.

There is no question that EGR reduces peak engine performance. Maximum power depends on how much stoichiometric mixture you can cram in to the cylinder. So you can think of EGR as a backwards turbocharger - power is always proportional to how much fuel you burn, so less fuel in the cylinders means less power ultimately. Ideally, if you eliminate the EGR valve you should also increase the main jet size to restore the cruise AFR that you would have with the EGR in place. Notice that AFR is a misnomer in this context, because "air" is really oxygen. EGR reduces the oxygen concentration, so it's not really AFR any more - instead it's the O2FR you desire to maintain.

Not sure what the legality of deleting the EGR system on an old car is - it really depends on state law. As I mentioned above, Federal law also applies, and I'm fairly sure under Federal law you can't legally remove anything that's emissions related. Not sure how that applies to engine swaps (if it's a 231) - I'm sure it varies from state to state. Unless the enforcement regime changes in the future, in the USA the states are in charge of emissions compliance. All the states (and localities within states) have different policies regarding inspection and enforcement. You can guarantee future compliance if you keep all the devices that went along with your engine (even if they are not required by your locality - the LCD approach).

 

The Federal codes technically don't allow for any removal or modification of virtually anything on a vehicle. Every lift kit is technically illegal. Every Saginaw conversion is technically illegal. Whether or not an authority having jurisdiction chooses to enforce the code is a whole other topic that will not be debated on this forum. The state of Washington has adopted the Federal safety standards and the State Patrol can and has enforced them. My dad was a state trooper that wrote lots of tickets for illegal bumper heights and impounded many rigs that were "unsafe"

 

In PA, if an engine swap is performed, the vehicle must meet the emission specs for the year of the engine rather than the vehicle the engine is swapped in to. But no one really checks that sort of stuff in my limited experience.

For stockers, older cars and trucks, like 96 and back have to pass only a visual inspection to see that the emissions equipment is on the vehicle. Doesn't really even have to work. Just has to be there. Newer stuff gets tested on the machine.