What is this and what does it connect to?

Engine, Transmission & Driveline

  1. 66MonacoWagon

    66MonacoWagon Active Member FCBO Gold Member

    Messages:
    232
    Likes Received:
    149
    Joined:
    Jul 2, 2017
    Location:
    Lemont IL
    In the lower left hand corner, cylindrical part. I have a vacuum hose coming out the end that is not connected to anything, and it looks like there might be another port at the top. It is a 71 440 - I'm still learning on this one...

    Many thanks
    Joe

    IMG_2441.JPG
     
  2. ceebuddy

    ceebuddy Well-Known Member

    Messages:
    602
    Likes Received:
    268
    Joined:
    May 13, 2014
    Location:
    Frankfurt, Germany
    Seems like your 1971 is a California car and has the NOx Sytem put into cars sold in California that year. The cylindrical item is part of the NOx system and is a solenoid vacuum valve. It disrupts vaccum to the distributor vacuum advance under certain conditions, i. e. if accellerating under 30 mph. You should also find a thermal switch mounted to the firewall in this car. 1971_NOx-System.jpg
     
    • Like Like x 1
    • Agree Agree x 1
  3. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

    Messages:
    4,774
    Likes Received:
    1222
    Joined:
    Mar 27, 2017
    Location:
    Cornelius Or
    Most of this style NOx devices were disconnected because of performance issues. They tended to not work as designed and often completely disabled the vacuum advance leading to sluggish performance and lousy gas mileage. Most likely why yours is disconnected. Check to see if the vacuum advance has been rerouted to a throttle plate port.

    Dave
     
    • Like Like x 1
  4. 66MonacoWagon

    66MonacoWagon Active Member FCBO Gold Member

    Messages:
    232
    Likes Received:
    149
    Joined:
    Jul 2, 2017
    Location:
    Lemont IL
    Yup - my vacuum advance goes straight to the carb. Is it recommended that I still bypass? I'm guessing yes.
     
  5. ceebuddy

    ceebuddy Well-Known Member

    Messages:
    602
    Likes Received:
    268
    Joined:
    May 13, 2014
    Location:
    Frankfurt, Germany
    Yes.
     
    • Agree Agree x 2
  6. 66MonacoWagon

    66MonacoWagon Active Member FCBO Gold Member

    Messages:
    232
    Likes Received:
    149
    Joined:
    Jul 2, 2017
    Location:
    Lemont IL
    I do still have the thermal switch and there is vacuum line running to it. Should I cap and disconnect from the system as well?
     
  7. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

    Messages:
    4,774
    Likes Received:
    1222
    Joined:
    Mar 27, 2017
    Location:
    Cornelius Or
    Yes, that will get rid of any possibility of a vacuum leak.

    Dave
     
  8. 66MonacoWagon

    66MonacoWagon Active Member FCBO Gold Member

    Messages:
    232
    Likes Received:
    149
    Joined:
    Jul 2, 2017
    Location:
    Lemont IL
    Many thanks to both of you.