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Technical 8ba flathead timing marks?

Discussion in 'Traditional Hot Rods' started by lorodz, Jan 23, 2014.

  1. lorodz
    Joined: Jul 26, 2009
    Posts: 3,728

    lorodz
    Member

    does anyone have a clean cam gear from a 8ba to show me what the top dead center mark looks like, i have the old style carbon cam gear and just want to make shure the marks on mine are aligned correct im having trouble getting the motor to run, all i can see is a small dot on a tooth i know their is supposed to a be a line but i cant see it to well...thanks and what does the dot point to number one cylinder?
     
  2. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,087

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    There is, or should be, marks on both the cam gear and the crankshaft gear that drives the cam. It is imperative to find both timing mark, other wise it is a complicated and time consuming effort to figure out where it (they) need to be.

    I've built a flathead, but it was about 5 years ago and I don't recall for certain the nature of the timing marks. Many engines have a single mark on the crank gear and a pair of adjacent marks on the cam, or vice versa, and you place the single mark between the two marks. If each gear has a single mark, then they would be aligned.
     
  3. lorodz
    Joined: Jul 26, 2009
    Posts: 3,728

    lorodz
    Member

    yeah i know the mark on the crank is plain as day, the cam gear not so much i do see a small dot but ive heard there was a line, that needed to line up with the crank, if thats tru where does the dot line up, does it face cylinder 1 ???
     
  4. hoop98
    Joined: Jan 23, 2013
    Posts: 1,362

    hoop98
    Member
    from Texas


  5. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,087

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    It doesn't face any cylinder. Line up the crank mark with cam gear mark and everything should be fine.

    As the crank and cam rotate the valves will open and close in relation to piston position. That is the valve timing...a separate thing from ignition timing.

    The ignition is timed to #1 cylinder in relation to top dead center (TDC). You bring the piston to TDC on the compression stroke, meaning both intake and exhaust valves are closed. The piston also comes to TDC on the exhaust stroke, with the exhaust valve open. That's why it is important to note that both valves are closed to verify compression stroke.

    When setting the initial ignition timing you do want the #1 cylinder at TDC on the compression stroke and then, when installing the distributor, your install it so that the rotor points to the #1 sparkplug wire in the distributor cap.
     
    Last edited: Jan 23, 2014
  6. lorodz
    Joined: Jul 26, 2009
    Posts: 3,728

    lorodz
    Member

    ok so that dot is the dot that gets lined up with the crank..correct ..cause i got misinformed than ....i was told that their is a very faint line in the cam gear and that is what lines up to the dot on the crank ...so i looked as closley as i could to what i thought was a freakin line in the gear and that dot points to about 9 o colck wich is why the engine wont fire god damn i knew i was correct and shoulda stuck to my gut instinct
     
  7. flthd31
    Joined: Aug 5, 2007
    Posts: 561

    flthd31
    Member

    Here's a pic of one I did recently. Aluminum timing gear has a line which I highlighted with white paint.
     

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  8. lorodz
    Joined: Jul 26, 2009
    Posts: 3,728

    lorodz
    Member

    im guessing the factory 8ba has a dot ?
     
  9. flthd31
    Joined: Aug 5, 2007
    Posts: 561

    flthd31
    Member

    I think the factory fiber gear has a dot, the factory aluminum gears had a line.

    The pic I uploaded earlier is factory 49-53 Merc.
     
  10. lorodz
    Joined: Jul 26, 2009
    Posts: 3,728

    lorodz
    Member

    thats what i thought but i cant find anyone who can give me a deffinite answer ..my firing order is correct and my crank is lined up and my distributor is at top dead but im getting a miss fire ..so i know i have the cam set way off ..im gonna pull the cover off this weekend and re check it ...i know i remember seeing the dot at 9 o clock
     
  11. hoop98
    Joined: Jan 23, 2013
    Posts: 1,362

    hoop98
    Member
    from Texas

  12. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,087

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    The only time the two marks are lined up is when you install them, and then every second full revolution of the crankshaft. The cam turns at half crankshaft speed.

    You mention that the dot was at 9 o'clock......was that it's position when you installed the cam gear and aligned what you thought was the timing mark 'line' ? If that is what you mean, then "yes" the cam is way out of time with the crank.

    Your focus on a 'line' versus a 'dot' is anguish over nothing. The timing mark could be either, depending on the manufacturer, and either is adequate for the purpose it is there.
     
  13. lorodz
    Joined: Jul 26, 2009
    Posts: 3,728

    lorodz
    Member

    this is what i thought...thanks for the help gentlemen.. i gotta a motor to pull apart ...
     
  14. hoop98
    Joined: Jan 23, 2013
    Posts: 1,362

    hoop98
    Member
    from Texas

    At least you can't bend the valves on that engine :)
     
  15. lorodz
    Joined: Jul 26, 2009
    Posts: 3,728

    lorodz
    Member

    thank god ...i would be pissed the * f * off....if i bent any valves, i just rebuilt this engine, I called a reputable place that builds flatheads and this is were i got the advice.. i knew that the dot was the mark, and maybe the guy i had spoken to was confused onto what timing gear i was using,,he said look for a line but, all i seen was a faint line and a dot so i used this faint line instead of the dot on their, i just hope this is the issue.
     
  16. hoop98
    Joined: Jan 23, 2013
    Posts: 1,362

    hoop98
    Member
    from Texas

    Hey my first timing chain job was a Y-Block, needless to say it doesn't time like any other engine , the dots are at 3 oclock, I think 12 links apart (hey that was 50 years ago. I got it right the second time, no valve damage.
     
  17. lorodz
    Joined: Jul 26, 2009
    Posts: 3,728

    lorodz
    Member

    hahah good job
     
  18. GOSFAST
    Joined: Jul 4, 2006
    Posts: 254

    GOSFAST
    Member

    Here's a shot of 2 sets, the one on the left is a new 8BA setup. You can see the timing marks clearly.

    We find them with both "lines" and "dots", I believe the "lines" are earlier, I'm not certain. The center shot shows the "lines".

    Thanks, Gary in N.Y.

    P.S. Where on Long Island are you located. I'm in the middle of assembling 4 stroker kits for shipment, one overseas!
     

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    Last edited: Jan 24, 2014
  19. lorodz
    Joined: Jul 26, 2009
    Posts: 3,728

    lorodz
    Member

    Hey guus thanks forn all the help lined up the marks god dam thing fired up almost immediately. ..runs great ji st have to break I in slowly.... video to follow soon.thanks again

    Posted using the Full Custom H.A.M.B. App!
     
    dwollam likes this.
  20. lorodz
    Joined: Jul 26, 2009
    Posts: 3,728

    lorodz
    Member

    Located eastern long island medford area..

    Posted using the Full Custom H.A.M.B. App!
     

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