Fast Idle Cam Replacement Q-Jet

Discussion in 'The Venerable Q-Jet' started by BuickV8Mike, Mar 5, 2020.

  1. BuickV8Mike

    BuickV8Mike SD Buick Fan

    My FastIdle Cam has split in two. How big of job is it to replace? What do I need other than the cam? Is there a link to a thread on this? Any help would be greatly appreciated. Best regards, Mike
  2. johnriv67

    johnriv67 Well-Known Member

    Everyday Performance will have the right one for your carb, give Ken a ring. It does not seem like a very involved job.
    mrolds69 likes this.
  3. BuickV8Mike

    BuickV8Mike SD Buick Fan

    Thanks John, I have the cam, just founding if it is as simple as a screw to replace?
  4. Cutlass

    Cutlass Platinum Level Contributor

    … make it two screws to replace :)
    Seriously, it is straight forward and takes less than 30 minutes. If you got the 1:1 replacement cam, there should not be any need for adjustments.
  5. BuickV8Mike

    BuickV8Mike SD Buick Fan

    Thanks Ralf. I was hoping it was that easy!
  6. Cliff R

    Cliff R Well-Known Member

    I'd recommend getting a metal replacement instead of a plastic one. They factory quit using plastic fast idle cams because they crack, melt, and aren't heavy enough to work effectively.......
  7. BuickV8Mike

    BuickV8Mike SD Buick Fan

    Thanks Cliff. How different are they 350 vs 400 vs 430 vs manual vs auto. If just the warm up profiles. Seems a little minor in the grand scheme.
  8. Cliff R

    Cliff R Well-Known Member

    Going from memory Rochester produced at least 35 different plastic secondary cams for those older units. There are two variety, one has a "cut-out" in it so it is raised by a tiny roll pin on the shaft (horrible design IMHO). The other variety is raised by a lever on center shaft that goes thru the bracket.

    Each division, Chevy Olds, Buick, etc uses completely different choke parts and different divorced choke on the intake. The lack of continuity makes parts interchangeability non-existent. The plastic cams are one of the fuel parts that interchange, and the plastic pull-offs fit many models, but all the choke parts mounted to the brackets are different. I'd add here since mentioning the early plastic pull-offs is that none of the ones currently being sold are that great. The spring inside is too strong and the hole in the fitting is WAY too big so release time is instantaneous. I have to modify every single one we sell or customers will call up and complain about their engines stumbling when they go quickly to full throttle. The choke pull-offs serve two functions, unloading the choke flap on a cold start and dampening the secondary air flaps when you go to heavy/full throttle to prevent hesitation/stumble/bog. You can NOT remove the link and wind the spring tight enough to make it work correctly although I see folks try this all the time....FWIW

    Anyhow, fast idle cams for all years come in many variety. Some have only one step, many have two, and others even more. This provides different fast idle speeds during warm-up.

    Once they went to hot-air chokes the parts are more interchangeable and all the 1975 and later hot-air and electric choke parts basically work for all models if you are converting to an E-choke.

    The metal fast idle cams started showing up in the later 1960's to replace the brittle plastic ones. With few exceptions most of the later metal cams used on divorced choke carbs will fit the early ones, unless you have the type that uses the small roll pin to lift it. Even those can be "slotted" or modified to work if you are good at that sort of thing.......Cliff

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