need your thoughts on this NOx Inspection sticker

[Francis F.]

DSC01910.jpgFound on windshield of my "66"coupe,car was delivered to the zone office in los angles june of 1966.
can anyone explain it's purpose ,thank's
Francis

[Jimmy P.]

Re: need your thoughts on this

Francis,
That appears to be window sticker designed and sold by the Bureau of Automotive Repair of the Dept. of Consumer Repairs. It is a California Highway Patrol Pollution Exemption Sticker.

[Francis F.]

Re: need your thoughts on this

Jimmy, that is very interesting,I can tell you the car was an original A,I,R,car delivered to California.Thank's for your input.
Francis

[Jimmy P.]

Re: need your thoughts on this

Francis,
If you google :" State of California Air Resources Board Resolution 74-56" you can read all about it.
Interesting stuff😊

[Duke W.]

Re: need your thoughts on this

California was first to establish NOx tailpipe standards for the '71 model year ('73 for 49-state cars) and as you can see from the link also required retrofitting a so-called "NOx device" for '66-'70 CA models that were not originally built to a NOx standard.

I didn't own a car in this model year group and don't recall seeing a retrofit installation, but it consisted of a "plate" installed between the carburetor and manifold. AFAIK it allowed exhaust gas to leak into the inlet manifold, so it was effectively a crude EGR system.

The retrofit "kits" were poorly engineered and not application specific, but rather generic for various engine families. As you can imagine they caused major problems with driveability and a lot of consumer complaints. I'm not sure if the requirement was ever dropped, but once those model years were exempt from emission testing most were likely removed.

I doubt that, today, you would ever run across a car in that year group with one of those abominations still in place.

http://www.arb.ca.gov/board/res/1970/74-56.pdf

Duke

[Joe L.]

Re: need your thoughts on this

California was first to establish NOx tailpipe standards for the '71 model year ('73 for 49-state cars) and as you can see from the link also required retrofitting a so-called "NOx device" for '66-'70 CA models that were not originally built to a NOx standard.

I didn't own a car in this model year group and don't recall seeing a retrofit installation, but it consisted of a "plate" installed between the carburetor and manifold. AFAIK it allowed exhaust gas to leak into the inlet manifold, so it was effectively a crude EGR system.

The retrofit "kits" were poorly engineered and not application specific, but rather generic for various engine families. As you can imagine they caused major problems with driveability and a lot of consumer complaints. I'm not sure if the requirement was ever dropped, but once those model years were exempt from emission testing most were likely removed.

I doubt that, today, you would ever run across a car in that year group with one of those abominations still in place.

http://www.arb.ca.gov/board/res/1970/74-56.pdf

Duke

Duke-------

I don't recall any plate installed between the carb and manifold. What I recall was a retrofit device that interrupted the vacuum signal to the distributor vacuum control under certain conditions. The device was often referred to as the "Echlin Device" since Echlin was one of the major suppliers of the state-approved devices. As you mention, these devices resulted in driveability problems and were usually "decommissioned" very quickly after they were installed.

I, too, would be surprised to find any vehicle of the era with an operable system still in place. However, folks often find remnants of the system still installed on the car, usually on the firewall.

[Duke W.]

Re: need your thoughts on this NOx Inspection sticker

Your memory is probably better than mine on this subject, Joe. I never had to deal with this and don't recall ever seeing such installed on a car, but I heard a lot of griping and stories, mostly bad.

I found the following link in a Google search:

https://www.facebook.com/QuinnsAutomotive/photos/pb.133235586140.-2207520000.1454969258./10153684002371141/?type=3&theater

It's nothing but a couple of vacuum caps to disable the vacuum advance - very crude! Disabling the vacuum advance will retard the spark enough at cruise to reduce peak combustion temperature enough to reduce NOx significantly. In fact, this technique (along with slowing the centrifugal advance) works equally well today, and it will also usually reduce HC and CO since the retarded advance increases EGT, which will keep an aged catalyst hotter and working closer to peak efficiency.

Byproducts are reduced fuel economy and possible hot running/overheating.

If there was some "plate" between the carb. and manifold, it may have been part of a more sophisticated package that rather than completely eliminating vacuum advance just eliminated it at light throttle cruise up to a certain load.

Most emission controlled engines of that era had ported vacuum advance, so there was no vacuum advance at idle in any case. One exception may have been the K-66 system on Powerglide 300 HP engines that had 40 degrees max centrifugal in the distributor and the initial timing setting was 4 deg. ATDC.

Duke

[Edward B.]

Re: need your thoughts on this NOx Inspection sticker

Duke, when we first moved out to So Cal in the mid 1960's, my dad purchased a 62 Impala for my mom to drive. Under the hood, attached to the firewall was a "NOX Box" (That's exactly what it said on it)! It was a small (approx 5" wide by 3" tall by 2" deep) red box, and it had a California sticker on it the windshield similar to the one Francis posted. Now granted, at the time I was only 10 years old, so I don't remember a lot about it, but I DO remember my dad saying it had something to do with the smog laws. Other than that I don't remember a lot about it. Our next door neighbor had a 1957 Bel Air (283) and it too had this "NOX Box" attached to the firewall, so it was used on cars at least back to 1957.

We lived in San Diego county, so other counties may have had something similar, but I've done numerous Google searches on "NOX Box" and have never found anything. I KNOW I didn't imagine it, but I do admit the details are a bit sketchy.

Ed

[Duke W.]

Re: need your thoughts on this NOx Inspection sticker

I believe the "NOx device" was only required on '66-'70 model years; '66 was the first year California implemented tailpipe emission standards, but only for HC and CO. PCV was required beginning in the '61 MY, and the first NOx tailpipe standards were 1971.

Of course anyone could have installed PCV or a NOx device on just about any car. Back in the seventies the smog in the LA basin was really bad. It was rare that I could see the San Gabriel mountains and Mt. Baldy, which is about 35 miles away from the top of the hill a couple of blocks to the west of my house a mile up from the beach. Nowadays it's rare that I can't see the mountains, and if they are obscured, it's usually marine layer.

The last Stage 1 "smog alert" in the LA basin was 1997. The last Stage 2 was in the eighties, and the last Stage 3, which is the most severe was in the late seventies.

Automotive emission control has done wonders for air quality, but the early systems were crude and problematic. The era of "modern" emission control began in the early to mid-eighties with the implementation of O2 sensors with electronic air-fuel ratio control and three-way catalysts that both oxidize HC and CO and disassociate NOx.

Modern cars are so clean that field emission test equipment can barely detect the amount. New cars typically emit low single digit HC in ppm (I've seen some register zero), zero percent CO, and maybe 100-200 ppm NOx. A pre-'61 car was several hundred ppm HC (as much as 50 percent of that could be from the crankcase) several percent CO, and several thousand ppm NOx.

Those are with the engine fully warmed up. On a typical trip with a cold start 80-90 percent of total trip emissions come from the first few minutes of operation until the car warms up enough to go into closed-loop air-fuel ratio control, so the focus of the industry now is to reduce those cold start emissions as much as possible.

Duke

[Francis F.]

Re: need your thoughts on this NOx Inspection sticker

thank's to all for your input to my question on my N O/X sticker,you have enlightened me a great deal,and I hope the info.continues to flow on this subject.as always Duke,Joe,and others continue to provide all members with a lot of great background details we all in the hobby enjoy.
Francis