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Premium Fuel, Timing, Advance, Oh my

Discussion in 'The Garage' started by 78Suburban, Oct 10, 2005.

  1. 78Suburban

    78Suburban 1/2 ton status

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    please help me out here guys..
    I got my distributor put back in and now at least the motor runs... but I need to get a timing light and set the timing... So I looked at the emmissions sticker, and the timing part is pretty much ripped off.. I MIGHT have made out an 8* BTDC... but I'm not sure.. So what should the timing be set at?? I still have a hard time understanding how the timing light works :o

    And also, on the sticker it said at the bottom REQUIRES 91 OCTANE or better.. Holy crap.. is this true? I've used regular 87 for the time I've had the truck, and I'm pretty sure the Po's used it for the last 15 years!! I haven't noticed any knocking (detonation) but I'm certainly no expert and might not know what to look for.. So is it true that I must use premium fuel in this beast!!?? WTF :confused:

    Thanks a million, please help me engine gurus... I know I'm a goofy
    noob :bow:

    here's what the old sticker looked like :crazy: [​IMG]
     
    Last edited: Oct 10, 2005
  2. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Found this on Autozone :D

    [​IMG]
     
  3. MTMike

    MTMike 1/2 ton status

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    8's about right for a stock 350. Thats what my sticker on my old '79 said.

    Ideally, you want just as much advance as you can get without pinging.

    Also, if you wanna run lower grade fuel, run it, if you get pinging, you can retard the timing a few degrees and be fine, or you can run higher octane fuel. With older non-computer engines you can get away with lower grade fuel by backing some timing out of it. At todays prices, run 87 and run 8 -10 degrees if it doesn't ping. Also don't forget about your mechanical advance curve - 8 is just your static timing.

    Mike
     
  4. 78Suburban

    78Suburban 1/2 ton status

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    will I know it for sure if it does start pinging?? so would 10* be less apt to ping than 8* with regular fuel?? I know nothing about mechanical advance curve :confused: .... good grief this stuff is confusing.. my brain is melting ahh! I need to go to school for this stuff :o ..
     
  5. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    You'll know if it pings , its loud enough to hear over the radio , unless you have 2 15 inch kickers :D
     
  6. theperfectgarage

    theperfectgarage 1/2 ton status

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    pinging

    10 deg. is more apt to ping than 8 deg. Dont let your brain melt, find books, magazines and search the internet. Better yet make a new friend in your area who can help you. Most gear heads are happy to help.
     
  7. MTMike

    MTMike 1/2 ton status

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    It's much simpler than it seems.... take a deep breath :)

    The further advanced it is (higher degrees), the more apt to ping it is. Pinging is a "marbles" sound caused when the air/fuel mixutre detonates or is ignited before the optimal time during the power stroke.

    Here's some reading material.
    http://chevyhiperformance.com/howto/97438/
    http://sporttruck.com/techarticles/33703/index5.html
    http://auto.howstuffworks.com/ignition-system.htm
     

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