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Rjetting and metering rods on an edelbrock Q-jet?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by rjfguitar, Dec 31, 2003.

  1. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    I have a stock edelbrock performer quadrajet on my built 406 and I have a lean mixture problem. A local carb shop wan't $100 plus to rejet it and change the metering rods.
    How hard is it to change these 2 things if I tried myself? I have never really messed with carbs before but I am very mechanicly inclined and pick up on things fast.
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    It's not too tough, just have to get the right parts.

    Where is the lean mix problem? Cruise only I assume?

    Pretty hard to get it spot on (too many variables in the metering rods, jets and power piston springs) without an exhaust gas analyzer of some type, but if it's the typical surge at cruise, richening up the primaries a bit should cure it.

    I just re-jetted a carb for an EGR 305 that went into a non-EGR C30, and made sure that the primary rods were just a hair richer at their thickest part to compensate for lack of EGR.

    Did the same thing with my Olds 403, noticeable surge at cruise after rebuilding the engine (bored out, slightly bigger cam, etc) and in this case I just swapped out the jets for one orifice size larger, and problem disappeared.

    Seems to have worked out great, no complaints from the guy, and none from my 403.

    The problem with changing this stuff without an analyzer is that you may be running it richer than need be, or at the wrong time, which could cost some MPG, or may not help cure the problem, or may not be the right solution. But, for $100, I doubt the other option would test it on their analyzer either, right? /forums/images/graemlins/smile.gif

    See if you can't find JUST the airhorn gasket for your application. I've reused these things before, as long as they aren't too old and brittle, but if it has a lot of miles on it, expect to replace it. Nothing worse than not having a part on hand when you need it.
     
  3. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    The $100 plus bucks covers tuning, jet change and analyzer to make sure it's right. Whats the air horn gasket?
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Then for $100, I think it's a good price. Airhorn gasket is the one that goes between the top piece of the carb (air horn) and the middle piece. (float bowl)
     
  5. K1Orion

    K1Orion 1/2 ton status

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    $100 for "analyzed" results sounds good to me.

    If you wanna try it yourself look here florida4x4.com Lots of good info on tuning quadrajets.
     
  6. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    Thanks guys, I bet it will be between 125 to 150 bucks when they are done but I think thats what I will do so that way I know it is right.
     

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