I'm Baffled

Discussion in 'Ranchero Tech Help' started by thegasman, Jan 14, 2020.

  1. thegasman

    thegasman In First Gear

    Messages:
    17
    Fairly new member here. Joined in Oct. and didn't think I'd be needing advice this soon. Here goes : bought a super clean 1973 Ranchero GT last year ( 2019 ). Posted pictures last year also. Gave it a tune up after purchasing. Replaced plugs, plug wires, cap and rotor, coil, and removed points & condenser and replaced with a Pertronix II kit. Timed engine and I was all set to go. Ran perfect. Ran car every 2 weeks weather permitting and ran great. A couple days before Christmas I took it out and it ran great for about 15 min. Got on it for a couple of seconds and then slowed down for a stop sign. When I stopped, noticed it was missing a little and then died. Started right back up and as long as I kept the RPM's above 2,000 it ran fine. When ever RPM's got below 1200, it was rough and missing. Gave it a tune up check the following weekend and everything checked out good if I keep the RPM's above 1200. NOW here's the BAFFLER, when I went to time it, I couldn't find the timing mark on the Har Bal with the timing light on the #1 wire. Move the timing light to different wires and wallah - there it was on the balancer in the right position ( 8 BTDC ) BUT the light was on the #4 wire and the #7 wire. I know #4 and 7 one was either on the compression stroke and the other was on the exhaust stroke but how could it be so far off the #1 cylinder and still run smoothly above 2000 RPM !! When I tuned it up this summer, every thing checked out ok including timing. I thought maybe bad timing light. Borrowed another one and the same thing. #4 and #7. Ranchero is all original including 400cu ( 6.6L ) engine. Timing order is 1-3-7-2-6-5-4-8 and the rotation is counter-clockwise. Since it's the original engine, I was thinking maybe loose timing chain and maybe it slipped a little, but you would think it would run rough no matter what the RPM was. I'm getting a little older now and I really don't want to pull the engine unless I have to SO any SUGGESTIONS would be greatly appreciated. Thanks EVERYBODY
     
  2. 72GTVA

    72GTVA Administrator Staff Member

    Messages:
    9,547
    Location:
    Chesapeake, VA
    I'm wondering if you didn't get a jump of the timing gear set, offset enough that when the centrifugal advance is all in from RPM it is "close enough" to let the engine run sort of okay. Otherwise, include me in the baffled world.

    Out of curiosity - did you just lift completely off the throttle quickly when you let up on approach to the stop sign?

    One way to diagnose it is to remove the passenger valve cover, distributor cap and spark plugs and observe the valve action as you hand crank the engine observing the push rods to estimate correct or incorrect action relative to crankshaft position. Or pull the timing cover and look at the timing set. Remember that 90 degrees of crankshaft rotation is equal to 45 degrees of distributor rotation.

    I'm sure other folks with better ideas will chime in shortly.
     
    HuevosRanchero likes this.
  3. 5.0 Chero

    5.0 Chero Bahumbug Staff Member

    Messages:
    13,934
    Location:
    Prunetucky California
    quite possible that the balancer ring slipped.
     
  4. Hillbilly

    Hillbilly In Maximum Overdrive

    Messages:
    5,658
    Location:
    Winchester, TN.
    Timing chain and cam gear time. Almost bet a $100 dollar bill. Pretty sure 73 still had the nylon capped gear teeth on the cam gear. Most of the nylon might not be there now. Pull the distributor cap so you can observe the rotor movement. By hand turn the engine over to take up the chain slack. Turn it over clockwise stopping at top dead center mark on the balancer. Now slowly turn the crank anti-clockwise until the rotor just starts to move. If you have 10 degrees of movement or more measured by the balancer marks it's time for a new chain and gears.
     
  5. burninbush

    burninbush In Maximum Overdrive

    Messages:
    8,310
    Location:
    near SF
    I'll agree with Hillbilly and 5.0 on the causes of your timing slips. It's a wonder it runs at all.

    But if replacing the gears and the balancer don't fix the idle problems, get a carb kit and replace the enrich valve on the carb; if that is leaking fuel at idle it'll cause a missing symptom just like what you describe.
     
    ForistellFord likes this.
  6. LSChero

    LSChero In Maximum Overdrive PLATINUM MEMBER

    Messages:
    2,141
    Location:
    Area 6 NV
    All great suggestions.Check vac advance plate in dizzy,make sure it isnt stuck full advance.I once romped on a cold motor,spun it up
    around 6k and bent 5 push rods.Something else to check.If timing chain checks out ok,Iam with BB on plugged idle circuit.Do a compression
    check to see what shape the motor is in.
     
    HuevosRanchero likes this.
  7. thegasman

    thegasman In First Gear

    Messages:
    17
    Thanks everybody for the advice. Hopefully it won't rain this weekend and I can try some of these things. I will pick up a compression tester in the next couple of days. Even though it's an old engine, hopefully each cylinder will be within 20 -25 psi of each other. Also going to try ' Hillbilly ' suggestion to hand crank the HB and see how much slop we got going on with the chain and gears. Sounds pretty easy to do. Thanks Hillbilly. And thanks to everybody else for their comments.
     
  8. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

    Messages:
    9,534
    Location:
    Everett, WA
    I agree, went through both on two different Fords. To verify balancer, you need to put #1 at TDC on either compression or exhaust, doesn't matter, and if the annulus slipped on the damper, the timing scale won't be under the pointer. Very simple. Then, you can check for timing chain slop. You turn the crank till the the timing scale shows zero degrees, then remove dizzy cap, and turn the crank VERY SLOWLY BACKWARD. If the rotor stays still for 15 or more degrees of crank rotation, you definitely need a timing set, and your poor running is from the chain jumping a tooth.
     
    HuevosRanchero likes this.
  9. 5.0 Chero

    5.0 Chero Bahumbug Staff Member

    Messages:
    13,934
    Location:
    Prunetucky California
    Motor would not run if timing chain "jumped" enough to make the damper line up with 4 or 7 my money is on Damper
     
    The Wrench likes this.
  10. pmrphil

    pmrphil In Overdrive GOLD MEMBER

    Messages:
    983
    I'm still leaning toward the Pertronix taking a dump. Got a Pertronix coil on there also? Other possibility is the distributor drive pin (gear) is broken?
     
  11. plumcolr

    plumcolr In Maximum Overdrive SILVER MEMBER

    Messages:
    1,320
    Location:
    Freehold NJ
    Cylinders 1 and 6 should show up at the same place on the balancer timing mark. The fact that it is near correct on 6 suggests you might have crossfire between 1 and another cylinder, or miswiring, or a slipped pertronix reluctor ring. Or perhaps low coil voltage at low rpm. #1 is right front, correct?
     
  12. DJ Clinton

    DJ Clinton In Second Gear GOLD MEMBER

    Messages:
    98
    Location:
    Mesquite, NV
    #1 is passenger side front.
     
  13. Hillbilly

    Hillbilly In Maximum Overdrive

    Messages:
    5,658
    Location:
    Winchester, TN.
    ??? Don't see how the balancer ring slipping could physically move the base timing until the distributor got moved to match the balancer timing marks. Something else happened first.
     
  14. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

    Messages:
    9,534
    Location:
    Everett, WA
    We really do not know what happened, which is why I suggested the two checks. What I don't know is if it's exhibiting one sign of retarded running, glowing exhaust manifolds, when the dizzy is turned to try to line up the timing marks from #1 wire.
     
  15. thegasman

    thegasman In First Gear

    Messages:
    17
    More suggestions. Thanks everybody. Storming out today so I still can't follow up on the old or new advise yet. And yes the #1 is the front passenger side. Yes I put in a new coil ( Pertronix 45,000 v ) when I installed the Pertronix II ignition kit this summer. I'll check the dwell and coil, if that is ok, that should eliminate any Pertronix problem. Yes the #1 and #6 are on the same place on the balancer but #4 and #7 are also on their own same place on the balancer according to the firing order and that's whats showing up with the timing light. Can't be a crossfire with #1 and another wire because #4 and #7 are showing up together like they should be. I'm not a mechanic, very vey far from it but I like to think I have a little common sense and a little tinkering ability if I know what to fix. I just don't understand how #4 and#7 can show up on the correct marks with the timing light. You would thing the engine would be back firing and bucking or not running at all at any RPM, not smoothing out at 2000 RPM like it does now. Just my $0.02 opinion. Not worth much !
     
    HuevosRanchero likes this.
  16. 5.0 Chero

    5.0 Chero Bahumbug Staff Member

    Messages:
    13,934
    Location:
    Prunetucky California
    slipping ring will not change base timing but it dose move timing marks giving the illusion of base timing being off
     
    HuevosRanchero and Hillbilly like this.
  17. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

    Messages:
    9,534
    Location:
    Everett, WA
    That's what made me think the annulus slipped.
     
  18. pmrphil

    pmrphil In Overdrive GOLD MEMBER

    Messages:
    983
    But the ring moving wouldn't explain why it suddenly started running poorly. The imbalance counterweight is included in the ring, so if it moved that much, it would vibrate noticeably as the RPM's were increased.
    P.S. I can't say annulus o_O :eek: Too many weird thoughts :oops:
     
    beerbelly likes this.
  19. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

    Messages:
    9,534
    Location:
    Everett, WA
    The 'poor running' can be a function of the changed balance of a slipped ring (better?). I'm interested to find out the results of what the OP finds.
     
  20. Hillbilly

    Hillbilly In Maximum Overdrive

    Messages:
    5,658
    Location:
    Winchester, TN.
    Had balancer rings slip before to fully 180 degrees out of position and only got vibration. Still would idle but had that obvious shaking that got worse with increasing rpm. Balancer failure on the ones I have had to replace did not make the engine shut off, even on the ones where the ring came completely off due to the rubber failing.
     
    pmrphil likes this.

Share This Page