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Vintage factory electronic ignition??

mca

Member
Joined
May 18, 2004
Messages
21
This is a question for Paul Newitt or any others that have something similar. 390GT/CS 4spd., factory GT car originally sold in san fransisco/daly city area. On "my" car, there was a metal "box" mounted on the passenger side shock tower with wires, and I think, a couple of vacuum hoses coming off of it. If I recall correctly, it had a small window with a cross hatch "aduster" wheel, similar to a radio trim adjuster, except larger in it. Was this a factory emissions device or some sort of electronic or rev limiting device? I still have it, and can post a pic of it, I just have to dig it up out of the garage. Have you seen or heard of this kind of item before?
 

murf104

Well-known member
Joined
Feb 2, 2003
Messages
274
I own a 1966 289 Conv equipped with Thermactor system that was purchased new in California. It too had the gizmo of which you speak. The unit was simply a device that controlled the ammount of vacuum that could reach the vacuum advance unit on the distributor and slowed the rate of vacuum advance occuring at the distributor. It did not limit the total advance but it did extend the time neccessary to reach full advance. It was known later in the automotive industry as an "OSAC VALVE" or more correctly an "orfice controlled spark advance". All vehicels in California had this in the early seventies, and the other 49 states were required to have this on all new vehicles sold beginning in 1974. The item you have was probably added in order to get your car to pass an emmisions test required, and was an upgrade from Ford specs. Take it off, purchase a new vacuum line, pur your car back the way Henry Ford intended it to be. and keep your trinket as a memory of when the automobile industry was trying to control pollution with antique mechanical devices in the age before microprocessors and electronic sensors. Murf
 

GTCS95616

Well-known member
Joined
May 25, 2004
Messages
51
Sounds like your car has been retrofitted with an emissions control device referred to as "NOx device" (NOx - Oxides of Nitrogen). The California Air Resources Board mandated the retrofitting of 1966-1970 cars with a NOx device upon transfer on ownership. There were several manufacturer and designs of approved NOx devices. Essentially, all of the approved NOx devices reduced NOx emissions by reducing combustion pressure by retarding ignition timing.
 

donsonn

Member
Joined
Aug 10, 2003
Messages
20
Sounds like it could also be a factory cruise control system, although it required an automatic trans.
 

68gt390

Well-known member
Joined
Feb 22, 2004
Messages
2,021
Location
Columbus, Ohio
For MCA:
I have a 68GT/CS 390 4speed and a 68GT 390 coupe, C-6 auto and neither one of my car's has that type of gadget on it. Not sure what you may have. Sorry, but what ever it may be sounds strange to me. Both my car's were built at the San Jose plant so if California had some type of emmisions set up on the California built car's I would think mine would have them. But, they may have been pulled long ago.

Don ???
 

GTCS95616

Well-known member
Joined
May 25, 2004
Messages
51
Post a photo of the parts and I will confirm whether it is the one of the devices I described in my previous rely.
 
OP
OP
mca

mca

Member
Joined
May 18, 2004
Messages
21
Thanks for the info. It does sound like the California emissions device that y'all spoke of. I did a brief search and it was not where I thought it was, but I will try to find it.
 
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