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Technical Flathead Timing

Discussion in 'Traditional Hot Rods' started by USMC4LIFE, May 11, 2020.

  1. USMC4LIFE
    Joined: Aug 5, 2012
    Posts: 34

    USMC4LIFE
    Member
    from AMERICA!!!

    53 flathead. Trying to figure out a timing issue. When purchased the engine was partially tore down (heads removed, carb off, and generator removed). Everything is reassembled and now we are troubleshooting what appears to be a timing issue. Setting the timing by the book leaves the car backfiring through the exhaust and sometimes the carb. Reset the pulley at TDC, pulled the distributor up, turned the rotor 180 degrees, and dropped it back in the hole. No more backfiring but no signs of wanting to start. Which why is closer to the truth? Any tips on finding actual TDC with the head still on the engine?
     
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  2. leon bee
    Joined: Mar 15, 2017
    Posts: 482

    leon bee
    Member
    from Arkansas!

    You can find TDC with your thumb over the sparkplug hole and just bumping the starter.
     
  3. 54vicky
    Joined: Dec 13, 2011
    Posts: 1,348

    54vicky
    Member

    do yourself a favour go over to the barn lots of flatty owners
     
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  4. 38bill
    Joined: Dec 20, 2019
    Posts: 59

    38bill
    Member
    from Minnesota

    There are several videos on YouTube that may help you.
     
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  5. 19Fordy
    Joined: May 17, 2003
    Posts: 6,815

    19Fordy
    Member

    If you are using the stock 8BA distributor do this:
    Turn engine over by hand by putting socket on crank pulley bolt.
    Engine turns clockwise when viewed from front of car. Rotor also rotates CW.
    Turn the engine CW with socket until the timing mark on the timing cover lines up with timing mark
    on crank pulley AND the distributor rotor points to the number one cylinder on the distributor cap.
    That is usually near 6 o'clock or a little past.
    Your number 1 piston is now at TDC on the compression (power) stroke.
    Engine should now start. If it doesn't. rotate the distributor a little CW or CCW.
     
  6. USMC4LIFE
    Joined: Aug 5, 2012
    Posts: 34

    USMC4LIFE
    Member
    from AMERICA!!!

    Your theory could still land you 180 off. Should TDC indicator be lined up right after number 1 exhaust closes or right before it opens? Remember, cranks spins around twice for every one camshaft rotation.....
     
  7. I see you usually work with General Motors engines .
    Don’t forget,,,the Ford cylinders are numbered. 1 -4 down the right bank,,,,5 - 8 down the left bank .
    If the wires were crossed before,,,it would backfire like you were describing,,,maybe it wasn’t 180 out ?

    Tommy
     
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  8. USMC4LIFE
    Joined: Aug 5, 2012
    Posts: 34

    USMC4LIFE
    Member
    from AMERICA!!!

    Firing order is correct. She is sparking at the plugs.
     
  9. Sorry,,,I was just checking,,,,,,it is really easy to get tripped up on that .

    Tommy
     
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  10. USMC4LIFE
    Joined: Aug 5, 2012
    Posts: 34

    USMC4LIFE
    Member
    from AMERICA!!!

    Yes, Sir. Understood.
     
  11. 19Fordy
    Joined: May 17, 2003
    Posts: 6,815

    19Fordy
    Member

    I've always had success with my method because when the
    timing cover mark and the crank pulley marks are aligned at the same time the rotor
    is pointng to #1 plug wire terminal on the cap, the engine is on the compression stroke, not the exhaust.
    It's not 180 degrees off. Guess , I was just lucky all these years.
     
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  12. ronnieroadster
    Joined: Sep 9, 2004
    Posts: 739

    ronnieroadster
    Member

    When its time to fire up a fresh Flathead or one thats been apart like yours I just take the time to get cylinder number one on compression ready to fire. Once I have that blast of air from the cylinder I then set the dist so the rotor is lined up with cylinder number one plug wire. Im sure you have already done all of this. Now at least the engine will fire up once its running I continue to advance the dist until the engine is running smoothly. Note I never use any books to get timing information. I find its best to set the initial timing as I wrote. Then I drive the vehicle and see how it feels. What I have determined after doing this for many years and on hundreds of Flathead's is that the initial timing will be from 8 to 12 degrees to get the Flathead running extremely well. Also in the past using Champion H-10 spark plugs I have experienced issues with skipping I now only use NGK plugs B-4L or B-6L
    Ronnieroadster
     
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  13. IronTrap
    Joined: Jul 13, 2011
    Posts: 459

    IronTrap
    Member

    Zip tie method works well for getting in the ball park. Stick the fat end of a plastic zip tie down the plug hole of #1 and spin engine over slowly by hand. You'll feel the piston bump the zip tie and you should be very close to tdc and check the valves to make sure you're on compression stroke. From there you should be able to set your rotor pointing at #1. If it's anywhere remotely in the ball park it should try to start. Mixed up plug wires and distributor/rotor rotation are common errors.
     
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  14. Ronnie to the rescue, again.
     
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  15. ronnieroadster
    Joined: Sep 9, 2004
    Posts: 739

    ronnieroadster
    Member

    Hi Nick I decided to take afternoon off from working on the next Flathead for Speedweek to post some info. Thought I might be able to help
     
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  16. Petejoe
    Joined: Nov 27, 2002
    Posts: 10,468

    Petejoe
    ALLIANCE MEMBER
    from Zoar, Ohio

    Last edited: May 11, 2020
  17. USMC4LIFE
    Joined: Aug 5, 2012
    Posts: 34

    USMC4LIFE
    Member
    from AMERICA!!!

    We are just trying to make sure the dist isnt 180 off. When it was first installed it popped back through the carb and exhaust. We pulled the dizzy, spun it 180, and dropped it back in. No we get no backfire and no signs of it wanted to start. Most people arnt understanding that the number one piston comes up twice during one cam revolution. Therefore the number one piston can be up with the rotor pointed at the number 1 cylinder AND the dizzy can still be off by 180 (because it will line up on the next crank rotation. I figured will all of these people that are "pros" with flatheads (including the idiots that say to look down the spark plug hole at the top of the piston) would realize this.
     
  18. USMC4LIFE
    Joined: Aug 5, 2012
    Posts: 34

    USMC4LIFE
    Member
    from AMERICA!!!

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  19. tubman
    Joined: May 16, 2007
    Posts: 4,994

    tubman
    ALLIANCE MEMBER

    Take the #1 spark plug out, put your thumb over the hole, and have someone else "bump" the engine with the starter. When it's on the compression stroke, it will blow your thumb off the hole if it's got any compression at all. Watch the "timing bump" as it may go past the pointer. Bring it back or forward so the pointer is pointing at the bump.
     
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  20. Petejoe
    Joined: Nov 27, 2002
    Posts: 10,468

    Petejoe
    ALLIANCE MEMBER
    from Zoar, Ohio

    Yes sorry. But still could apply.
     
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  21. 51504bat
    Joined: May 22, 2010
    Posts: 1,841

    51504bat
    ALLIANCE MEMBER

    What he said^^^^
     
  22. choppedtudor
    Joined: Nov 28, 2009
    Posts: 667

    choppedtudor
    Member

    you probably had the distributor right the first time, the popping and backfiring may just be valves hanging open....
     
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  23. 19Fordy
    Joined: May 17, 2003
    Posts: 6,815

    19Fordy
    Member

    USMC4LIFE: Are you sure the timing gear
    and crank gear timing "dots" are lined up?
    Are you sure 8BA the timing gear on the end of the cam shaft has not rotated
    off its "assembly mark" with the cam? It's only pressed on. Not a very good design.
    I had that happen once.
     
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  24. tubman
    Joined: May 16, 2007
    Posts: 4,994

    tubman
    ALLIANCE MEMBER

    8BA cams are bolted on. It's the pre-war units that are pressed on.
     
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  25. rusty valley
    Joined: Oct 25, 2014
    Posts: 1,516

    rusty valley
    Member

    i think you can see the edge of the valves in the plug hole with a flashlight. when both #1 valves are closed and piston is up you are close enough to TDC. rotor points to #1 plug tower on the cap, fire it up
     
  26. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 2,878

    Flathead Dave
    ALLIANCE MEMBER
    from So. Cal.

    Since you did all of that, did you watch the valves to see of they are opening and closing properly?
    Could be that they aren't closing properly.
    Only use a book for reference. Don't rely on them 100% of the time. Use your ears. You'll find a big difference.

    We used to use match book covers to set the points where the book will be too specific. Are your points set properly?
     
  27. leon bee
    Joined: Mar 15, 2017
    Posts: 482

    leon bee
    Member
    from Arkansas!

    Where are these idiots you mention? I've done this a number of times lately. Do the thumb deal, like we said. While looking at the bump on the pulley, (hopefully you got one). Now, this has happened to me 3 times in a row: I had my timing mark lined up, #1 cylinder on compression stroke, rotor pointed right at the wire for #1 plug. But...........I was still one tooth off on the distributor gear. When I've done that, sometimes she'll start and run real rough, sometimes won't quite start. Move it one tooth and everybody happy.
     
  28. USMC4LIFE
    Joined: Aug 5, 2012
    Posts: 34

    USMC4LIFE
    Member
    from AMERICA!!!

    Point are gapped correctly and valves are moving freely and not sticking.
     
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  29. USMC4LIFE
    Joined: Aug 5, 2012
    Posts: 34

    USMC4LIFE
    Member
    from AMERICA!!!

    It ran before the heads were removed for paint. Distributor was also removed.
     
  30. USMC4LIFE
    Joined: Aug 5, 2012
    Posts: 34

    USMC4LIFE
    Member
    from AMERICA!!!

    We'll give it a go. Updates to follow.
     

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