how do you get total timing

Discussion in 'Engine Topic' started by ThumperZ28, Oct 7, 2011.

  1. ThumperZ28

    ThumperZ28 Veteran Member

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    Ok. I got 10btdc @700rpm ...but how do I determine total timing? At what degrees? @what rpm?..what would determine at what degree? What would determine at what rpm?..
    Also spark plug gap I got .045. .what happens at a. Closer gap..? Wider gap?
     
  2. muscl car

    muscl car Veteran Member Lifetime Gold Member

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    The small block chevy runs best with 34 to 38 degrees total timing.

    Ok let me break it down for you..

    You have initial timing which is the timing at idle.. Then you have the mech. advance in the dizzy.. Most dizzy gives 18 to 22* of advance..

    Total is timing at idle, + mech advance..

    The right way to check total is with a dial back timing light..

    Remove and plug/cap off the vac advance hose, Rev engine to 3500 rpm and hold there.. Shoot timing light at damper, and turn knob on back of gun (or push button) untill the line on damper lines up with the 0/TDC mark on timing tab... Now read the number the gun's knob is sitting on... That is your total timing.

    Now if you don't have a dial back light, you can degree your own damper, or put timing tape on it, and use a std. gun... Just rev engine to 3500 rpm, shoot gun on damper and what ever # on timing tape around damper that lines up with 0/TDC mark on tab is the amount of total you have.

    You you can use math to get close.

    As I said most HEI's will give 18-22* of mech. So split it and go with say 20*

    36* total = 20* mech + X (16 in this case)... So that means you will need to set timing to 16* BTDC at idle with vac advance line un hooked
     
  3. muscl car

    muscl car Veteran Member Lifetime Gold Member

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    on my 11.1:1 LT1 sbc i'm running 16deg btdc /38 deg total or 23 deg initial/38 deg total at 3500rpm .this is a mallory unilite mech adv distributor if this helps any
     
  4. night rider

    night rider Veteran Member

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    That total timing info looks like one of my old post to that same question asked awhile ago by a diff. member. lol
     
  5. Pfrederiksen

    Pfrederiksen Veteran Member

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    Your total timing is much more relevant than your base (or initial)
    More times than not, it's best to set your all in at 34/38 or wherever your motor is happy and let your initial fall wherever it may.

    P
     
  6. COPO

    COPO Veteran Member Lifetime Gold Member

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    Last edited: Oct 7, 2011
  7. Z-WIZZ

    Z-WIZZ Veteran Member

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    is it true the old school guys can time by ear? adjust to highest rpm then back off a hair?
     
  8. vegas1974z28

    vegas1974z28 Moderator Staff Member Lifetime Gold Member

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    bad idea....
     
  9. FatnLow

    FatnLow Veteran Member Lifetime Gold Member

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  10. night rider

    night rider Veteran Member

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    Sorry, but no, nobody can really time an engine by ear. You can get it running that away but you sure can't be dead on. It takes so little movement to change the timing a degree or two.

    If you have a combo thats on the edge of detonation, like my old one was. It would ping with just 1* too much timing put in it.
     

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