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Final Timing adjustment

Discussion in '40- & 55-Series Tech' started by xumFJ40, Mar 29, 2004.

  1. xumFJ40

    xumFJ40

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    Hey guys,

    I am tring to finalize the timing on my '75 2F. I set the timing static when I put in the new dizzy w/pertronix, and now I want to put the light to it.

    I see the white mark on the crank pully(DS) that I am supposed to be looking for, but I don't see anyway to "measure" where it is at. Is there supposed to be some kind of scale? What am I supposed to be lining that white mark up with?

    Thanks,
     
  2. Landpimp

    Landpimp

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    there is nothing on the crank pully , the timing marks are on the flywheel, there might be a little cover over it, its right above the starter. You want to set the timing to the BB not the TDC line.
     
  3. xumFJ40

    xumFJ40

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    Hmmmm.....

    What is the little white mark on the crank then?

    I thought that setting the the flywheel to the BB was setting the truck to "Static" timing. I did this before I installed the dizzy.

    To get this strait, I am supposed to finalize the timing by now putting the light on the flywheel and adjusting the dizzy untill the BB lines up with the needle?

    Thanks,
     
  4. IDave

    IDave

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    Yes, that's the idea for factory timing. Then there's the fact that these engines often like some advance beyond it.
     
  5. xumFJ40

    xumFJ40

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    Cool....

    I will check it tonight.
     
  6. xumFJ40

    xumFJ40

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    Ok,

    I set the timing dead on the BB on the flywheel. The idle slowed a bit and the engine got a good bit louder. In order to get the timing set, I had to rotate the dizzy about 1/8 turn cw.

    So, according to IDave these engines like to be advanced sometimes....would that be turning the dizzy cw or ccw...in other words did I have it advanced before I set it w/the light? Just to clarify, when I turned the dizzy cw to get the BB in line w/the needle, the BB came from the right of the inspection window...

    I hope this is clear as mud.

    Thanks
     
  7. IDave

    IDave

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    I'm not entirely familiar with the 2F timing window, but it seems like it would have to be just like the F, since you are looking at the front of the flywheel. In which case, advanced is with the timing ball below the pointer, retarded is above the pointer. With the dizzy, advanced is turning CCW, retarded is turning CW.

    As far as fine tuning the timing, I have a collection of suggestions from a number of people. Obviously, timing is going to vary with elevation, age and type of your carb, the jetting of your carb, and age of your engine and the valve train.

    Some people do their timing by the "Ping" method, which involves stopping at the bottom of a hill, then driving up it shifting up to high gear and "romping" on the accellerator. Adjust the advance on the dizzy until the engine just starts to ping at the top of the hill. If it pings a lot, you are just too advanced.

    The other method I am familiar with is the maximum vacuum method. Some people say to attach a vacuum gauge and advance the timing to the point where the vacuum is highest, and leave it there. Others say to do that, then retard the dizzy about 2 degrees from there. Still others say to retard the dizzy so it drops 1 inch of mercury from max vacuum.

    You can't really tell by looking at the timing ball where you are as far as degrees before TDC with a normal timing light. The ball drops below the window at about 2 degrees of advance, equivalent to 9 degrees BTDC, I'm told. So, beyond that point it is a guess, or you buy or borrow what is called an advance or dial advance light.

    One of the pros I've read posts from says that at 4200 feet he usually ends up with about 5 degrees of advance, or 12 degrees BTDC.

    I don't have a dial advance light, so I have gone by max vacuum, then retarded a little until it seems to be running smoothely.
     
  8. xumFJ40

    xumFJ40

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    Thanks IDave.

    Should it make a difference whether or not the vac line is attached to the dizzy? For reference, I have a 2/75 2F w/ the stock carb(rebuilt) and a '68 dizzy(vac advance) w/Pertronix.

    Thanks
     
  9. Landpimp

    Landpimp

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    timing should be set with the vacuume hose on the dizzy disconected(but at idle should make no difference)

    TO check you vac adv, suck on the hose(leave end on the dizzy, suck on other end) the RPM at idle should go up if the advance is working.

    Then conect vacuume hose, rev motor to 2k, as you do so you should be able to see the BB move(down, advance) on the flywheel(use the timing light)

    John H

    [quote author=xumFJ40 link=board=1;threadid=13911;start=msg130240#msg130240 date=1080745631]
    Thanks IDave.

    Should it make a difference whether or not the vac line is attached to the dizzy? For reference, I have a 2/75 2F w/ the stock carb(rebuilt) and a '68 dizzy(vac advance) w/Pertronix.

    Thanks
    [/quote]
     
  10. IDave

    IDave

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    Yeah, as John says, it should make no difference at idle (there should be no vacuum at the vacuum port off the carb at idle; it is there to advance the timing during accelleration). Most folks would say, however, to remove it and PLUG the hose just in case there is a vacuum leak (within the carb).