Ok, why the smell

Discussion in '1970 - 1973 Specific' started by Citrus70, Dec 10, 2012.

  1. 71flh

    71flh Veteran Member

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    Jun 1, 2010
    DFW
    The OP seems unable to say anything more than (to paraphrase) "it smells bad."

    Thus, it seems impossible to provide answers other than engines w/o cats smell different.

    Maybe he should get a Prius. No doubt they smell nice.

    Oddly, I have 3 stinky vehicles and find myself smiling after running any of them ;)
     
  2. Gary S

    Gary S Administrator Lifetime Gold Member

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    Apr 14, 1999
    Bismarck, North Dakota
    It depends on how sensitive your nose is. My Son has a friend who owns a Prius. Every time he rides in his friend's Prius, the battery fumes make him sick. So, the Pruis stinks too, but it has a different stink.
    And, oddly, my Son isn't bothered by the smell of his 1969 El Camino. That doesn't make him sick.
     
  3. Citrus70

    Citrus70 Veteran Member

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    Sep 3, 2012
    SW Ohio

    Why are there always the smart ass comments. Leave your thread crapping else where please.
     
  4. lumpy12

    lumpy12 Veteran Member Lifetime Gold Member

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    Sep 16, 2012
    NorCal
    I'm a shy lurker here but I thought I'd chime in here. My son and I have a 73 RS and it stinks too. It has an Edelbrock Performer RPM top end kit 350 (supposedly about 410HP) and a Demon 650 carb, dual 2.5" exhaust out the back like stock with a crossover, Richmond 5-speed, 4 wheel discs, etc. etc.
    I've dialed in the carb and timing and know they're right on. Not only by reading the plugs but the car has a an Autometer wideband air/fuel ratio gauge which tells me I'm right in the stoichiometric sweet spot.

    We got the car about 3 months ago and put a whole new exhaust on it - headers back - and then got the stink. I asked the muffler guy who built the system, and he's convinced it's because of the rear spoiler is creating a swirling area behind the car and a negative air pressure zone inside the car.
    We've found that with the windows rolled up while driving the car is sweet and smell free. Roll the windows down and it's stink city. You can feel the exhaust moving into the cabin from the back. No smell when sitting still by the way.

    I had some OER trunk weatherstripping (which sucks big time) but this weekend I'm putting some new Metro Molding from Pete at FBodyWarehouse and we'll see if that helps. I've also resealed around the tail lights as there was some leakage there, checked the drain plugs in the rear fenders, plugged some old muffler hanger holes, etc.

    I'll post up when I've solved my stink problem!

    Tim
     
  5. kdracer73

    kdracer73 Veteran Member

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    May 12, 2010
    OC, Ca
    I was in the drive through the other day , and the people behind me where holding their noses and waving their hands in front of their faces :confused:

    I do have a bit of a cam, so the idle is a little unsteady. As I told my Mother once.....I didn't build it to idle, I built it to be be quick !
     
  6. Bamaro

    Bamaro Veteran Member

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    Dec 24, 2004
    Jacksonville, Md
    I love the smell of exhaust in the morning.
     
  7. Citrus70

    Citrus70 Veteran Member

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    Sep 3, 2012
    SW Ohio
    Well it is not a burning oil smell. It is burned fuel smell, not of raw gas fumes but spent gas. Now lean or rich I don't know but I'd bet that is the main issue.
     
  8. muscl car

    muscl car Veteran Member Lifetime Gold Member


    yep the smell of race gas like VP C12 !!!!!:) :)
     
  9. shad_van

    shad_van Veteran Member

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    Jun 15, 2012
    las vegas, NV

    the Q-Jet is probably one of the best carbs ever designed. but all carbs need tuning for their proper application. most Q-jets of the for 71 and latter were designed for low performance, low compression engines, which is why they work on almost every engine.

    However 67-70 Q-jets had a wide range of applications. the main diffrence is the power piston spring and the idle air bypass that are diffrent on the 67-70 carbs. The low performance cams of the 70s produced a lot of manifold vacuum, with a 70 and eariler performance carb, the power piston spring will be too light holding down the power rods, creating a lean condition and stumbles at off idle and part throttle, while running rich at idle. and most likely rich at wide open throttle.

    what makes the q-jet such a universal carb is the secondary air control valve and its spring tension that i will control the amount of air entering the carb at full throttle.

    Holley's use a vacume diaphram or mechanicaly linked secondary, and carter/edelbrock carbs use a counter weighted butterfly valve. so with those it is eather all or nothing on the secondaries. so if you put 750 cfm carb on a stock low performance 305 you will over carberate it. but a 800 cfm Q-Jet on the same 305 will run fine because the seconday air spring will only allow enough air to flow to feed what the engine need. additionally the small primarys on the q-jet allow for a very crisp throttle responce. almost as good as fuel injection when properly tuned.
     
  10. Citrus70

    Citrus70 Veteran Member

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    Sep 3, 2012
    SW Ohio
    "However 67-70 Q-jets had a wide range of applications. the main diffrence is the power piston spring and the idle air bypass that are diffrent on the 67-70 carbs. The low performance cams of the 70s produced a lot of manifold vacuum, with a 70 and eariler performance carb, the power piston spring will be too light holding down the power rods, creating a lean condition and stumbles at off idle and part throttle, while running rich at idle. and most likely rich at wide open throttle"

    That said how should the carb be adjusted since it is a 70 carb on a mid 70's motor????
     

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