1970 electra 455 start up after years of indoor storage

Discussion in 'Street/strip 400/430/455' started by vancouver z, Nov 13, 2018.

  1. vancouver z

    vancouver z Member

    startin it up was no real issue, but its running pretty rough. changed the plugs, the spark plug leads, the points, condenser, rotor, dist cap, and its better but still noticeable missfire even at idle. what do i do next or is it carb rebuild for sure. suggestions anyone?
     
  2. Mark Demko

    Mark Demko Well-Known Member

    Old gas or gummed up carb.
     
  3. Schurkey

    Schurkey Silver Level contributor

    Cylinder balance test, followed-up with cranking compression test and cylinder leakdown testing depending on what you find. Figure out which cylinders are affected, which then gives you clues as to what is wrong.
     
  4. BuickV8Mike

    BuickV8Mike SD Buick Fan

    Send the distributor to Everyday Performance for a rebuild/recurve.
     
  5. Stevem

    Stevem Well-Known Member

    Time to soak and rebuild the Carb.
    Be sure to get a kit with a good acceleration pump as I think even the so called better Blue types have been known to fail quickly.
     
  6. agetnt9

    agetnt9 Agetnt9 (Dan)

    Check vacuum hose leak. Pull plug wires off one at a time and you will know witch one or two are weak cylinders.
     
    455 C-10 likes this.
  7. Schurkey

    Schurkey Silver Level contributor

    That's one way to do it. Really hard on the coil and all the insulation of the secondary ignition system, though.

    Better would be to use a test light. Ground the wire, put some dielectric grease on the pointy probe. SLIDE the probe between the wire and the distributor boot until the spark grounds through the bulb filament (the light does not flash when this happens.) No sky-high voltage, no stress on the insulation, and when you're done, you haven't poked any holes in the plug wires.
     
  8. vancouver z

    vancouver z Member

    further to this resurrection... points condenser rotor and cap changed, plugs and wires are new, carb is now rebuilt and filter is new. same issue. rough idle, hesitation on initial acceleration, and still backfires through the carb under load. next on the list? what is the most likely issue. original block, 70,000 miles
     
  9. vancouver z

    vancouver z Member

    your estate wagon will be the same engine... help... what would you suggest next???
     
  10. Schurkey

    Schurkey Silver Level contributor

    1. Doesn't matter what's "new", what matters is whether or not it's functioning properly. Lots of brand-new defective junk available now.
    2. What happened with the various tests that were suggested? I don't see that you've done any diagnosis, not even the stuff we recommended.
    3. "Hesitation on initial acceleration, backfires through carb" both suggest a lean condition. What is the fuel pressure? Does the accelerator pump WORK?
     
  11. Philip66

    Philip66 Well-Known Member

    Doesn't really matter for diagnosis, but was it parked 10 years ago in excellent running condition or was it parked because it was having drivability issues?
    Sounds like a timing issue to me, check operation of vacuum advance.
    Put a timing light on it and see what's happening at idle and when you accelerate.
     
  12. hugger

    hugger Well-Known Member

    Sticky valves are common after sitting also, put some seafoam in it, certainly won't hurt to do it
     
  13. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I created a major headache once by hastily cranking a 70 350 that had sat for yrs. It had 2 or 3 stuck valves that resulted in bent pushrods and ruined lifters. Of course the heads came off too.

    The car was stored indoors and looked great otherwise. That was a kick in the ass.
     

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