Vacuum advance can bad?

Discussion in 'Small Block Tech' started by MrSony, Oct 11, 2018.

  1. MrSony

    MrSony Well-Known Member

    Wouldn't pull a single inch of vacuum with a hand vacuum pump. Pump works, I tested an old can I have off of a '76 350 HEI, holds but leaks down. Pump will hold all day with my finger over the end of the hose.
    It's a TA distributor, kind of sucks that it might be bad. It's brand new, has less than 6,000 miles on it.
     
  2. MrSony

    MrSony Well-Known Member

    Or, since I'm dumb and realized I've never checked it, could it just be out of adjustment?
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    You never noticed it wasn’t working when you checked your timing with a light? I’m not sure what canister TA has in their distributor. The Crane adjustable canister adjusts both amount and rate independently. There was an Accel unit that adjusted amount only. Both units use a small Allen wrench through the vacuum opening, but with the. Crane unit, it only adjusts rate (spring preload).

    https://www.jegs.com/i/Accel/110/31...MIqPuD0Kn-3QIVQZyzCh05dAXuEAQYAyABEgJLR_D_BwE

    https://www.jegs.com/i/Crane-Cams/271/99600-1/10002/-1
     
    Last edited: Oct 11, 2018
  4. MrSony

    MrSony Well-Known Member

    I guess looking back at it now, with the hose was connected to manifold, the timing never changed from the 8* I had it set at, same with ported vacuum port, unless I raised the rpm past bout 1200. Mechanical works, I guess the can doesn't. Engine doesn't seem to really behave oddly at any rpm range. I guess MPG could be better, it's about 10-12. I'm gonna tinker with it, my guess is it's so far out of adjustment (TA wants you to adjust it yourself I'm guessing), it's not functioning. It'd be a bad vacuum leak if it was punctured or something.
     
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Sounds like it might be a vacuum leak now. hook up a vacuum gauge and either disconnect or pinch off the vacuum advance and see if the vacuum reading changes. It might not, but you should find out. If it won't hold vacuum, replace it.
     

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