Rich running 455

Discussion in 'The Venerable Q-Jet' started by batsong, Jan 18, 2009.

  1. batsong

    batsong Well-Known Member

    I set the dwell to 26 using a meter. Vacuum gauge is first on my list.
    I don't know any tests for intake leak. I do have a little oil coming out of the the front of the intake by the distributer.
    One thing I did was plug up the intake (brake booster, pcv, trans etc.), and cover up the breather hole on the valve cover with duct tape. With the intake plugged, The duct tape swells (pressure), with it normal and unplugged, I get vacuum through the valve cover.

    I found an Imperial site that tells how to diagnose problems using a vacuum gauge:
    http://www.imperialclub.com/Repair/Fuel/VacuumGauge/index.htm
    Thanks for all of your help, Gabe.
     
  2. Graniteman

    Graniteman Active Member

    Real easy old time low-tech check for vacuum leaks:
    have your car at idle take a good size rag and cover the top of the carb like you want to smother it, block off all air flow, if the motor speeds up first before it dies you've got a vacuum leak. When you do this it should of course start to die right off. If you've got a leak I'll bet it's a bad one.
    If not a vacuum leak then your problem may either be with the power piston or maybe the float.
    Are you sure the power piston is moving freely? A good way to check that it's free is use a plastic drinking straw; motor off, slip the straw down the tube above it and you should be able to move the piston up and down with the straw. (straw is good 'cause you won't hurt anything with it)
    Does the motor run nice and smooth or does it surge at cruise speeds?
    I know you said the carb is all fresh but are you sure the float isn't sinking?
    Sure is lots easier to figure this stuff out in person:rolleyes:
    Good luck, hope I at least gave you a couple of new ideas.
    Mike
     
  3. flynbuick

    flynbuick Guest


    I believe the dwell should be 30 degress if you are using a stock points system. I know it is 30 for the 71 and 70 nodel years since I have owned those and set them many times.
     
  4. batsong

    batsong Well-Known Member

    My manifold vacuum is reading 13 for a few seconds then 14 for a few seconds. I tried to find specs on what to expect for my cam and ended up calling Crower. They told me that the cam I have, which is #52241, should have installed straight up. Well, we installed the three way key 4" retarded. Both Crower and T/A Performance says the front of the engine has to come off and the timing gears have to be reinstalled at 0'.
    -Gabe
     
  5. DaWildcat

    DaWildcat Platinum Level Contributor

    Sounds like good advice.

    A long time ago I ran a Crower one step up from yours, 52242 in my 436 and it was a real ripper. 238°/242° @ 0.050", 0.538"/0.536" lift. It went in 4° advanced to help out the bottom end a bit.

    Devon
     
  6. batsong

    batsong Well-Known Member

    Don't temp me, Devon!
    I think I'll put in normal the way Crower suggests. I don't know why we did not do that to begin with. I know the 3 way key instructions said that for more H.P. - advance (left key facing the front of the engine), and for more torque, right key. Sounds like I have to move the gear one key counterclockwise and rotated the crank 'til the marks on the gears line up.
    It's hard to believe that 4" would make such a difference, but for more power and better efficiency, it's worth a try. I'm only worried that I might have damaged the engine by driving it.
    Thanks, Gabe
     
  7. Turbo455

    Turbo455 James

    I wouldn't think you would have damaged it. It would just be a little slugish in lower rpm's.
     

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