Distributor Question

Discussion in '40- & 55-Series Tech' started by Boaf 32, Dec 8, 2018 at 2:31 PM.

  1. Boaf 32

    Boaf 32

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    Fellow LC'ers,

    I have a question on some acceleration issues I am having with my 1972 LC with 2F engine.

    As I am driving, and accelerate hard (not flooring it, just trying to get up to cruising speed)

    1. Engine starts to hesitate (almost like a rev limiter if you know what that feels like)
    2. Timing is BB dead ball accurate.
    3. Idle is smooth at 650RPM
    4. Dwell is bordering on passing, points exactly per spec.
    I have a distributor that others have (pictured here).

    My question, how do I get rid of the "rev limiter" feeling. I always have suspected the distributor was not up to spec and thinking of changing it out, or sending for a re-build. I felt no play when removed (wobble) but that may cause the "Rev limiter". What are your thoughts out there? Re-build, replace? upgrade?

    Thanks,

    Boaf.

    20170426_114948.jpg
     
  2. thebigredrocker

    thebigredrocker SILVER Star

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    What carb are you running? Does it have a ported vac fitting for the vac advance dissy? What’s your vacuum reading warmed up at idle? Should be 18-19 AFAIK. A vac gauge in the cab is handy. Temporarily running a handheld gauge in cab is an option. If running an Aisan carb, strong vacuum is critical to get proper fuel mixture.

    If vac is good, you might try a pertronix unit in current dissy. Can always rebuild dissy or buy new dissy later. Pertronix works awesome with stock ND coil.
     
    dlzadl and mrboatman like this.
  3. Dizzy

    Dizzy

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    Your centrifugal advance might be sticking? They get rusty in there. The plastic bushings on the governor weights inside the distributor go bad too. An advancing timing light could reveal problems with that.

    Humm, your PCV filter is on the front side of the motor. The filter on the back side of the pushrod cover isn't upside down?
     
  4. Boaf 32

    Boaf 32

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    I will pull the distributor and see if the centrifugal advance is sticking. That makes sense to me since it bogs down.

    Not sure I follow the second points. That is the way the motor came to me and re-assembled it in the same way. If I recall, the pushrod cover could only go on one way. Can you add? Thanks I appreciate it.
     
  5. Boaf 32

    Boaf 32

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  6. Dizzy

    Dizzy

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    FJ40-FJ60 2F Engine Pushrod Cover

    It probably is correct, it is just that it is on the side which is different and there is a top and a bottom on the back side (photo above).

    FJ40 Valve push rod side covers

    If your engine hesitates, does it do it when cold, warm, or both?

    As bigredrocker chimed, what kind of carb are you running? Have you checked valve lash recently? Are the spark plugs straw color, black, or white?
     
  7. emac

    emac

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    Maybe the tranny is on the wrong end or it is a right hand drive :)
     
  8. Boaf 32

    Boaf 32

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    Now that's funny right there mate'.
     
  9. Boaf 32

    Boaf 32

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    Hi Dizzy, thanks!

    Yep, valves or spec, it runs so smooth at idle, not enough ooo's in smooth to describe it. I downsized my carb from a 38 / 38 Weber to a 32 / 36. I was spewing black smoke and it would run even with the fuel adjustment completely shut off.

    The hesitation is always. Like I said, not pushing the accelerator, it's great. Gas to get some speed, and it sputters. I also noted when trying to advance the dial on the dizzy (Advance, Retard) it does hit a solid when trying to advance. Meaning I don't feel the advance moving at all, not even a little. Maybe rust or frozen mechanical advance. I will check vacuum, and then mechanical.

    I have always suspected the distributor as shaky at best. We'll know in a few days. Anything else I should look for?

    Thanks,

    Boaf
     
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  10. Dizzy

    Dizzy

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    Did you time it with the ported vacuum disconnected? Have you re-jetted your carb with a readout connected to an O2 sensor? How many turns out from seated is the idle mix screw? What is your elevation above sea level?

    The 32/26 shouldn't technically idle at idle, meaning that there is no way to get more air into the intake without opening the idle speed screw to the point where you are running on the main circuit and creating some draw on the ported vacuum line.
     
  11. brian

    brian SILVER Star

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    You have a Weber and a fuel pressure regulator right?
     
  12. Boaf 32

    Boaf 32

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    Dizzy, Brian,

    I had a pressure regulator, no matter what the pressure (3 or 7) same functionality. I may go buy another because the regulator was a $20 cheapie, may not have been the best.

    Yes on removing the vacuum before timing.

    Have not jetted the carb, factory carb. Started at 2 turns out as factory suggested. now at 1 1/2.​

    So pulled the distributor. I hate to theorize, but the Advance retard was all the way forward to Advance. That's how the distributor was dropped in TDC. If that is the case, the mechanical advance had no place to go.

    Thoughts on that SWAG Dizzy, Brian?

    Sometimes, you just need to step back and not over correct. I'll drop it back in this afternoon.

    Customer: My computer wont go on.
    If it's not working, is it plugged in?
    Are you using the CD drive as a coaster?
    Is the duck's mouth upside-down?​

    Boaf
     
  13. brian

    brian SILVER Star

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    So fpr is removed?
     
  14. Boaf 32

    Boaf 32

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    Yep.

    So took out the distributor, re set points, set the Advance / Retard to the middle. BB on center. Yep, same thing. Weights are free and moving for advance. Took it for a ride and going up a hill in 3rd is the bogging down, and a pop out the carb. Hard acceleration, same thing. Arghh

    Frustration! Can it be too lean fuel? Old school says pop out carb, timing.

    Boaf
     
  15. Dizzy

    Dizzy

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    The advance/retard moves the breaker plate; the centrifugal advance moves the cam. Together the two systems account for spark timing, but they are independent in operation.

    How many turns in on the idle speed screw? How many out for the idle mix screw?
     
    Last edited: Dec 9, 2018 at 5:44 PM
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