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308QV air injection system removal question

Discussion in 'Technical Q&A' started by tf308, Mar 30, 2004.

  1. tf308

    tf308 Formula 3
    Silver Subscribed

    Dec 14, 2003
    1,122
    Virginia Beach
    Full Name:
    Tim
    I have an 84 QV that I am removing the air injection from. I have removed both air rails from the heads, and sealed the heads off.

    My question is in relation to the "pressure Switch" that sits below the coolant tank. It looks like it meters the pressure past the air rails and the intake manifold pressure. What does this pressure switch do, and how should I plug it off correctly?

    Anyone done this?
     
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  3. Harta320

    Harta320 Karting

    Nov 6, 2003
    169
    Sarasota, FL
    Full Name:
    Bill Smith
    Hey tf308, I am thinking of removeing my air injetctions rails from the heads of my 83 308. How tough are the front rails removal and what did you use to plug the wholes? Thanks

    Bill
     
  4. Dave

    Dave F1 Rookie

    Apr 15, 2001
    2,722
    Little Rock
    Full Name:
    David Jones
    If you are going to remove the emissions equipment from your car,
    then you need to remove all of it, not just remove the rails.
    Look at your manual for the picture of the entire system.
     
  5. tf308

    tf308 Formula 3
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    Dec 14, 2003
    1,122
    Virginia Beach
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    Tim
    The cat is already gone...the only thing left are these airrails that run to the air box and one line from this circuit to this switch I am asking about. There is nothing else.

    The 83 had airpumps but not the 84 and 85.

    Not hard to remove the airrails w. the motor out.
     
  6. Harta320

    Harta320 Karting

    Nov 6, 2003
    169
    Sarasota, FL
    Full Name:
    Bill Smith
    Hey guys, Yes All of my air injection stuff has been removed except the air injection rails. I bought it this way. The air injection rails are actually connected together by a hose. It took me awhile to figure out what the hell was going on. The cats are still on and the car runs great but I would like to just get rid of the injection rails. What did you use for plugs in the head ts308, Dave, anyone? By the way Dave great write up on the suspension rebuild!

    Thanks
    Bill
     
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  8. Mark 328

    Mark 328 Formula Junior

    Nov 6, 2003
    510
    Orange, Ca
    Full Name:
    Mark Foley
    "My question is in relation to the "pressure Switch" that sits below the coolant tank. It looks like it meters the pressure past the air rails and the intake manifold pressure. What does this pressure switch do, and how should I plug it off correctly?"

    It sounds like this "pressure Switch" is the Auxiliarly Air Valve (AAV). It is part of the Jetronic system which creates the fast idle upon start-up. if you don't want this, I would be intersted in it.

    Mark
     
  9. Sophia

    Sophia Formula Junior

    Aug 17, 2003
    298
    Dash Point/Federal W
    Full Name:
    Peter Barbin
    Guys, I'm in the process of making some head plugs to replace the air-injection nozzles. I have M14 SS "Allen" drive bolts that will be machined down to spec. Steve Magnusson's drawings and Peter308GT4's photos gave me the inspiration. I have 100 bolt-stock units ready for machining. Within the next two weeks I hope to secure a machine shop to do the turning work. I'll sell sets of them as soon as they're done.

    Price TBA, and they will have projection tips to fill the void where the nozzle shaft passes through the head. If, you're interested, send me a Private Message here on the site and I'll keep everyone posted on the progress.
    PeterB.
     
  10. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    20,468
    Texas
    Full Name:
    Steve Magnusson
    Peter B. -- I just want to clarify/restate that that plug design is to replace the air injector nozzle (108205) of the 2-Valve 308 heads (carbed or "i"). I don't know if it would work on a '83 308QV head per this thread. I do know that the '83 308QV does not use the same air injection nozzle as the 2-Valves so I have a concern that it probably wouldn't (but I don't know that for sure). Anyway just wanted to point out that '83 QV's might need a different plug design (unless someone can confirm that design would work).
     
  11. Sophia

    Sophia Formula Junior

    Aug 17, 2003
    298
    Dash Point/Federal W
    Full Name:
    Peter Barbin
    Thanks Steve, I appreciate your input...and the drawings you sent me some time ago. I will do some research on the QV's spec. I'm curious now what the differences in the nozzles are between the 2V and 4V heads. ;)
     
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  13. Matt Morgan, "Kermit"

    Matt Morgan, "Kermit" Formula Junior

    Nov 12, 2003
    405
    Ferndale, WA
    Try looking into oil pan drain plugs. They are often the exact thread, and as a bonus, not only are they inexpensive, but short too!
    HTH
    Kermit
     
  14. Sophia

    Sophia Formula Junior

    Aug 17, 2003
    298
    Dash Point/Federal W
    Full Name:
    Peter Barbin
    If you use plugs without an "extension tip" to fill the void where the air-nozzle shaft passes through the head, an obnoxious 'chirping' sound will be part of your exhaust system's note...This has been fairly well documented in archive information. Since replacing the plugs will be a major pita, I think I'll believe the numerous accounts I've read! PeterB.
     
  15. Sophia

    Sophia Formula Junior

    Aug 17, 2003
    298
    Dash Point/Federal W
    Full Name:
    Peter Barbin
    Hey folks, I've finally produced a batch of 2V Air-injection nozzle plugs...100 plugs, getting a final "fit" correction at the machine shop. I'll post photos and such information when I have them home ready to ship.

    But back to the QV/328 Air-injection system and to complete SteveM's commentary. These cars are still new enough that not too many people have removed the system...smog laws. I went to a number of shops talking to well known F-car mechanics, and yet nobody could give me a positive answer. So after inspecting the progress on the 2V plugs I'm getting made, I stopped by Ferrari/Maserati of Seattle; the parts guys weren't too busy so we broke open all the parts manuals for the 3X8 cars. The 2V cars use P/N 108205 and the QV/328's have P/N 121718...They are completely different.

    For all their help I purchased the P/N 121718 plug ($9.00) and as I type its sitting in front of me. Part Description: "UNION"...it's virtually identical to the plug "union" used on BMW 2V twins from 1981-1994 for their air-injection system. M16 x 1.5. Yes, I used an off the shelf oil drain plug to replace my "union" when removing the air-injection system from that motor.

    The Ferrari QV & 328 exhaust ports are significantly different than the 308 2V. Obviously the shape is more 'rectangular' for the 2 exhaust valve flow-out, and the casting is flanged out from the head, where the header pipes greet the head. Atop this flange the "union" threads in. It threads in with a copper washer/gasket leaving a threaded male above the hex (cone shaped on the inside) to accept the female fitting from the air-rail.

    There is no "nozzle" associated with the P/N 121718. This system appears much easier to access and plug than the 2V cars! PeterB.
     

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