Wow at the difference

Discussion in 'General Maverick/Comet' started by satchelmcqueen, Jul 13, 2019 at 12:20 PM.

  1. satchelmcqueen

    satchelmcqueen Member

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    So after experimenting between ported and full manifold vacuum, all i can say is WOW!
    Ive drove the car now for several weeks with ported and fiddling with the va advance and it did ok but didnt really seem to have any get up and go. Idling was good for the most part, but in gear it would start to stumble sometimes.... Other times not.

    Today i went full manifold and set the VA locked out fully to the right with the adjusting screw. From this point the idling went perfect... Never stumbled again and held smooth no matter how long i sat there in gear. The takeoff and get up and go was damn scary with anything past 1/3 throttle....for me at least lol. Im not used to that little car behaving this way.

    I adjusted the VA advance to half way (8 turns....with 16 turns available) and it rattled bad under load. I then went 4 turns back right and it calmed down a lot. Finally settled on 3 full turns from 0 right. This gave me the least rattle and the get up and go was still maxed from what i could tell when i got on it hard.

    Im having a hard time hearing ping because im not sure really what it sounds like.... And the headers are so loud. Is ping the same thing as valve rattle?

    Total timing is set at 35 at 3000rpms. Initial falls at 12 advance. With VA hooked up it idles at close to 30. Adjusting idle doesnt change this 30 nor does adjusting VA canister....at idle. I assume this is ok. I adjusted idle to 850 in park.... It falls at 650 in drive.

    I just want to be sure im not killing it, but i have reduced the valve rattle sound almost completely and it runs very well.
     
  2. Jaybee

    Jaybee Member

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    That rattling is the ping of preignition, not valve rattle. I say that because it varies with ignition timing, which valves wouldn't do. Back off just the point it goes away and you should be fine.
     
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  3. satchelmcqueen

    satchelmcqueen Member

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    Ok ill back timing off to about 6 advance and see if that goes away. Just needed to be sure what i was hearing. Thanks.
     
  4. satchelmcqueen

    satchelmcqueen Member

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    Ok tried it at 6 adv and dead zero. 6 made the rattle less and zero sounded the same as 6. ill stay with 6.
     
  5. Jaybee

    Jaybee Member

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    How about backing out a little more vacuum advance and cranking in a bit more initial advance?
     
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  6. Crazy Larry

    Crazy Larry Member

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    You shouldn't run more than 20 initial. At wide open throttle, the vacuum advance isn't doing much at first, so your pinging is coming from the fact that you have too much advance at low RPM under a load.
    Personally, I'd run ported vacuum, and whatever initial that 36 to 38 total at 3000 RPM produces.
    If the idle is stumbling with ported vacuum, you have another problem (like incorrect air/fuel mixture or vacuum leak).
    I'd adjust the vacuum can to produce 10 degrees of advance. You could be at 48 cruising on the highway and the engine would love it. Wide open and the vacuum advance would disengage so you don't destroy the engine with pinging.
     

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