What model Mopars used the NOX valve

I believe the NOX valves were on air cleaners. My road runner (California car) had one on the air cleaner as did my wifes' 73 charger (Federal car). I think the 73's had a temperature switch (???) mounted on the firewall. I'll have to look that up when I get back home though. I'm in Phily right now and headed to Maine. Will be back home in a week or so...

This is the valve you're talking about right?

I think it's an OSAC valve.

Tav

Sorry I don't remember the specific year of this car, but I know it is a 72-74 E body.

Tav

Nearby I found another OSAC valve like that on a 73 VS29 valiant or scamp 2 door sports hardtop

Also nearby was a very used & rusted but complete 74 'cuda with the 360 4 barrel engine, and it did NOT have that OSAC valve on the firewall.

Tav

I found this air cleaner on a car at a show in Daytona Beach. I'm pretty sure the car was an E body, but I don't remember much else about it. Lots of stuff had been changed, so who knows where they got this air cleaner. I took the picture because I've been meaning to ask... What's this thing on the side of the air cleaner?

Tav

My dad's 73 has the valve that you are talking about. It also has another valve of some type right next to it on the passengers side. The picture above just shows a block off plate where the valve is on dad's car.

Please explain the valves purpose and if it needs attention before I start reassembling the car. Are they available new?

Here is some more info I've gathered. It's reliability is slightly questionable, so you might want to double check its accuracy.


In 1970 all cars used the Cleaner Air System (CAS)(PCV valve, valve cover vent, etc. In 1970 California cars used the Evaporation Control System (ECS)(fuel vapor setup) in addition to the CAS system.

In 1971 the ECS & CAS systems were used in the other 49 states, while California cars went to the NOX system in addition to ECS & CAS. The NOX system includes special components for the transmission, a special camshaft with more valve overlap, and a 185 degree thermostat. There were 2 different setups available depending on manual or auto trans.

Manual trans = a switch on the trans sensed what gear the car was in. any gear below high gear made a solenoid cut off the vacuum from the carb to the distributor vacuum advance unless the temperature sensor indicated the underhood temp was less than 70 degrees.

Auto trans = similar to above, but used a speed sensing switch inline with the speedometer cable.

In 1972 the ECS & CAS systems were used in the other 49 states, while California cars went to the Orifice Spark Advance Control (OSAC) & Exhaust Gas Recirculation (EGR) system in addition to ECS & CAS. OSAC is a firewall mounted valve with hoses to the carb and distributor vacuum advance. EGR is a valve on the intake manifold with a temperature unit on the firewall. The EGR system had slight differences depending on what engine was in the car. (318 ported, 340 floor jetted)

In 1973 the ECS, CAS, OSAC, & EGR systems became standard on all cars. I'm not aware of any differences for California cars in 73.

In 1974 the ECS, CAS, OSAC, & EGR systems were still standard on all cars. California cars used a venturi vacuum amplified EGR setup.

Tav

here's a pic of the NOX solenoid on the firewall.

Tav

The NOX soleniod looks like it would fit in this cutout on the firewall of my '71 /6 pilot Barracuda?



I should probably figure out which hole belong and which need to go away before painting.

I agree, that's for the NOX solenoid Dan. Is the car coded for california emissions on the fender tag? Do you have the original transmission, wiring harness or anything else that would indicate an NOX setup?

Tav

I'm assuming that odd solenoid valve (never saw that one before) must have a gasket. I'll have to look for one at Carlisle.

Here's my NOX valve that I took off the firewall when I restored my car< it is a N95 71 challenger. You can see part of the gasket left.

Here's the entire harness except for the speedo sending unit. Hope this helps.
PS I put it back on the car to fill the holes in the firewall.

Before:

After:

Thanks. Now I need to get a gasket. One guy said he'd send one. Hope he does. Would like to add to my firewall kits.

Bringing this back from the dead....

Heres 3 pictures from a customer. What is THIS firewall valve (THE ROUND ONE - it's not an OSAC)? (I see one plate above that has the same shape).

pic #2

and finally the firewall cutouts (this is a 73 E body)

Picture above shows a plate with same shape.

Wonder why these even have gaskets cause they don't go into the car. These go into the area where the wiper linkage is. Right?

All models sold new in California 1971 and later Mopars should have them

BTW, my 1971 340 Duster's NOX unit was bolted to the firewall with no gasket.

Hey James...The NOX valve was the only one that had a gasket. Yes, they just go into the wiper linkage area. Some modles had the valve on the air cleaner. Maybe it was just a carryover from needing one on those applications. I have seen some NOS valves that have the gasket already attached.

One other thing...I've seen some 73 Challengers that have the vacume valve on the left and others that do not. The ones I've seen don't even have the hole cut in the firewall for it. My car was built in Sept/Oct of 72. I wonder if new regulations starting on Jan 1st 1973 made them relocate that valve to a new location. Does anyone have a 73 modle that was built in 73 that still has that valve on the firewall?

Here is a 73 Challenger that was at the Nats this year. It does NOT have that valve or the firewall hole for it.

burdar, good info and thanks for the picture. It's going into my KNOWN MODEL/YEAR firewall stuff file

The six sided valve IS the OSAC valve. It says it right on the valve. It is part #3656585

The smaller one is part #3656660. It delays the vacume signal to the EGR valve under acceleration for 15 seconds. It is listed in the 73 parts manual as a vacume control valve.

If you didn't already know...I'm the one your making those gaskets for.

gasket fit to template.

I used the same gasket material as seen in Challenger1's OSAC valve picture above.

I like!

You may be onto something. I found a picture of a 73 Cuda that was built in Sept/Oct of 72. It is a 340 car and has a plate over the hole in the firewall for the vacume valve. I'll try and post a picture of it tonight.

Maybe only the 318 cars got that valve. The 340 cars had a plug over the firewall hole up until the beginning of 73 when that valve was either moved to a different location or not used anymore.

EDIT: OK, I just found another picture of a 73 340 Challenger and it has the plate bolted over the hole in the firewall. I emailed the owner to see if the car was built in 72 or 73. My guess is that it was built in late 72.

EDIT: That Challenger was built in Feb 73 so that doesn't help my theory. The owner said his car did NOT have an EGR valve. Is that correct? I figured the EGR was standard emissions stuff by then.

Bringing post back from the dead

I'm making the emmision related gaskets to put in my firewall kits. The one 6 sided gasket I've seen in 2 different materials, the dark foam and the off white foam. What have others seem?

Also the gasket on the right, there is another ones thats very similar. Does anyone have one of those?

This is a picture from above that shows the emmision item that has a similar but different gasket shape.

This is the one I need if anyone has an old one.

3-70 The date I assume.

Heres another. just bought off Ebay to use for reference. Looks like gasket is just a donut without ears. Odd. Like yours aboove 6bblgt

From listing....
"Essentially the same unit with different bracketry, this auction is for two firewall mounted NOX spark advance control units used on various Mopar A, B, C, and E-bodies with 225, 318, 340 engines.
1 has number 3656078 stamped on it (1973 ?) and the other has number 3438484 (1971 ?) stamped on it."

Is he determining that from those numbers? Are theose Julian date codes? part numbers?

there are also some NOS NOX and OSAC valves. I SHOULD snap them up for reference but kinda hate to "invest" the $. Never enuff $.

NOS like the one posted above. If I remember correctly, it's for auto trans cars only. It's my understanding from the parts books these were only used on non-high performance cars with engine sizes up to 383 and 2bbl carbs.
Can't remember why I even have it.

another pic

one more

Then there's this NOX valve solenoid dated 970. Not sure where it is mounted (and can't remember why I have it).

another view

My 1971 340 3 speed Duster (SPD 10/04/1970 LA Car) came with the NOX setup, my firewall piece looks exactly like Dans pilot car unit (flat metal plate with 2 male prongs). I would kill to find a mint original 1971 340 A-body manual trans harness to use as a pattern to reproduce them. I did manage to get the automatic version reproduced but they are different.