Weird ignition timing..why is my mark not where it should be??
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  1. #1
    Rods 'n' Sods Junkie [JP]'s Avatar
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    Weird ignition timing..why is my mark not where it should be??

    Hi all... quick question on ignition timing, not sure what's going on here.

    it's a 69 302 out of Camaro.
    Car runs well, drives well, power is there, no noises when static and on idle or revving it. Under load there's a tic tic tic noise but that could be due to an exhaust leak or also a split park plug cable I've just noticed.

    back to the timing, as I wanted to check it all, just to be sure. My OCD demanded it.
    Done the usual stuff...
    #1 spark plug out, finger on the hole, turn engine by hand, here's the compression stroke, pencil down the bore, slowly bring it right to the top, check marking against the tab - a few degrees off where the tab shows zero, but that could have moved, nonetheless, now I know where TDC is on the tab.
    Marked the line on the balancer with white marker.

    Unplugged dizzy advance from carb vaccum port.
    Plugged carb vaccum port.

    Hooked up my auto-advance gun (I have a digital snap-on), started the car...looked at my gun, increased it to 6, expecting to see the white line on the zero.....nothing! or even the gun at zero and the white line showing 6 or 8 or thereabouts on the tab. nothing.
    I thought, that's strange..... right...let's increase the numbers on the gun (meanwhile i'm still on idle), and as I increase here comes the line showing up.

    By the time the line is on the zero on the tab my gun is showing 36. - I'm still on idle at this point. I thought, this is strange??
    Anyway, increased the revs, expecting to see the line starting to move, as they usually do...... nothing.
    stays there. no move at all. revs increase....line on zero, gun showing 36.

    Now this would be all very good as it would tell me I have 36 total advance..... but what about my idle?? what's happening here?

    Why is there no line showing on idle about 6 to 12deg range, then shows up when i'm on 36deg and stays there even if I increase the revs??

    any idea what's going on?
    I checked the rotor in the dizzy and I have movement there.

    thanks
    JP

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  3. #2
    richard rawlplug Torment's Avatar
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    There is two different balancers on a small block.


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    Rods 'n' Sods Junkie [JP]'s Avatar
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    this is what looks like on mine...

    The white is what I marked up on the groove that was on the balancer, and where it is sitting on the photo is at TDC, but the zero on the tab is the yellow line I drawn on the photo.

    sorry I dont understand what you mean there's 2 balancers and how it affects what I'm seeing, I have done the timing when I had my 350 and my 302 ford and it was always fine and the line would move as the revs increased.

    Have MOT on Thursday so I can send it with paperwork to register with DVLA, and although the car runs fine and only that tic noise as I drove it up and down the road, now I'm worried about driving to MOT, although that's only 1 mile away.


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    Rods 'n' Sods Junkie roscobb's Avatar
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    roscobb is online now
    Not unknown for the outer part of an older balancer to rotate to a new position
    Carburation suck'shttps://www.corvetteforum.com/forums/customavatars/avatar199184_4.gif

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    Rods 'n' Sods Junkie [JP]'s Avatar
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    Quote Originally Posted by roscobb View Post
    Not unknown for the outer part of an older balancer to rotate to a new position
    Yes I can understand that happening, and if so that would mean where the TDC points at is not a big deal, as long as now I know where zero actually is on the tab.

    But what about the fact of marking not moving with the revs? how is that possible? there might be a technical explanation and I'm all ears as I like to learn and this might be something I never heard before.
    and will it be ok to drive it 1 mile to the MOT?

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    Administrator blackpopracing's Avatar
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    You have movement in the dizzy - but is it locked out at a pre set advance?
    Also check the vacuum advance by sucking on the pipe to see if it moves it. (I know this is disconnected for your initial timing but it's good to know it works)

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    Off the Xmas card list kapri's Avatar
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    Fully electronic newish dissy??

    Had this twice now where getting the wiring the wrong way round brings in ALL advance at tickover and as you rev it actually retards??

    In the case of the one I had hands on it was detonating just as it moved so NO I wouldn't drive it until timing sorted.
    Last edited by kapri; 03-11-2020 at 18:50.

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    Rods 'n' Sods Junkie [JP]'s Avatar
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    Quote Originally Posted by blackpopracing View Post
    You have movement in the dizzy - but is it locked out at a pre set advance?
    Also check the vacuum advance by sucking on the pipe to see if it moves it. (I know this is disconnected for your initial timing but it's good to know it works)
    errm.. that is a good question! I have movement on rotor anti-clock wise
    does sucking on it makes it move? I think I tried before on a previous car and it wouldnt make it move, but was working alright. I will check tomorrow. But, as you say it wouldnt play a part on what's going on with the markings right?

    Quote Originally Posted by kapri View Post
    Fully electronic newish dissy??
    Sorry, forgot to add that detail, nothing electronic, I hate those things, good old points and a coil.

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    Rods 'n' Sods Junkie
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    budetta is offline
    Sounds to me like the dizzy is stuck on full advance.

  13. #10
    Administrator blackpopracing's Avatar
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    Do the weights in the top move out? If so how far?
    Maybe take a photo with the dizzy cap off with the weights at rest and then photo it with you pulling the weights out as far as they can go?
    It may have really light springs with a locking stop so all the advance is in on tickover?

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