Engine idle and timing

Discussion in 'Ranchero Tech Help' started by bnorwood, Jul 26, 2021.

  1. bnorwood

    bnorwood In Third Gear

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    Well, Leigh ('61 Ranchero, 144cid, manual column shift) is finally back on the road. Been driving her here & there to work out the kinks (leaking wheel cylinder, leaking master cylinder, fuel pump failed). Check. Drives okay, but I felt like it was running a bit rich based on fuel economy (I used to normally get about 24mpg).

    So, tonight I was going to do a quick check of the idle & mixture, and verify the timing.

    I got the idle tweaked in fine. But then, when I checked the timing, it was about 14° BTDC!! Per the book, it should be 6°. The only trouble is, when I try to retard it to spec, the engine dies and will not re-start. I've tried raising the idle, but I still have to put it back to >10° BTDC to get it started, and even at fast idle (which slows down considerably as I retard back towards the proper spec) it ultimately stalls out.

    So where am I on this? Are my carb settings so far out of whack that I've got to blow those to heck and get the timing in the ballpark, then go back to fine-tune the idle and mixture?

    I'm no novice, but I was losing patience so I decided I'd get a sanity check from the Brain Trust (that's you folks!!) before I pulled out what's left of my hair.

    Thanks!

    Brad
     
  2. Hillbilly

    Hillbilly In Maximum Overdrive

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    Sounds like the outer ring on the front crankshaft balancer has slipped. If it has moved your timing marks moved with it. Try this, disconnect the vacume advance then bump the timing advanced untill you get a hard hot start condition. Then back the advance off untill it will start normally when hot. Reconnect the vacume advance then do a test drive while listening for spark knock. You may have to retard the timing a bit more untill the spark knock is gone. Now you can go back and tweak your idle speed and idle mixture screws. Your initial timing will fall somewhere between 6 to 10 degrees using this method. A new balancer is the ultimate cure but record what you see for a reference point untill the balancer is replaced.
     
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  3. pmrphil

    pmrphil In Maximum Overdrive GOLD MEMBER

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    Just verifying, but you were checking timing with the vacuum disconnected, correct?
    Hillbilly's method of setting timing is the best way to achieve ultimate driveability and mileage, very old school, and very dependable.
     
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  4. grebaba

    grebaba In Fourth Gear

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    What I do is disconnect the vacume advance and hook up a vacume gauge.
    Then adjust the timing to get the highest reading on the gauge, then back off a pound or 2 on the gauge and lock it down.
    Then I make sure it will start easy at that setting and listen for ping.
    We had quite a few cars come into the shop with no timing pointer on them and I found this method to work real good.
    Greg
     
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  5. burninbush

    burninbush In Maximum Overdrive

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    My old-school method ... connect the distributor advance to manifold vacuum, and then rotate the distributor to get max rpm. Essentially the same thing as previously posted. Be sure to test the starting with the motor warm.

    That said, if the balance on your crank pulley has slipped, get that fixed soon.
     
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  6. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Yup, it slipped. If you turn the crank till the #1 piston is at TDC, then mark the damper at the pointer, that at least tells you where TDC is. If you measure the distance between TDC and 6° BTDC, then make a mark from your new TDC mark, it'll allow you to time the engine. Don't forget to verify dwell if you have points, change them and the condenser if they're over 10K miles old. Then set your timing.
     
  7. bnorwood

    bnorwood In Third Gear

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    192
    Faulty vacuum connection and vacuum advance seem to have been the main culprits.

    I got it adjusted to specs, but now I seem to have a flooding problem (I think??)

    Startup is fine. Took it out for a spin today, made two stops, restarted fine both times. Then after driving 10-15 minutes, I turned onto our road (right turn) and went 150 yards or so stumbling & bumbling before she quit.

    I keep trying to start it, and it’ll catch, but if I do much as tap the accelerator she dies.

    I got her going once, but trying to get her in gear it’s like she wouldn’t pull a load so I didn’t really get anywhere.

    Carburetor rebuild? Other suggestions/questions??

    Brad
     
  8. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    I'd say more of a lean condition, but your spark plugs will tell you which way the carb's going. A good-running engine with carburetion should be a light sand to medium brown color on the ceramic, depending on how you drive and how the carb is set. What carb do you have?
     
  9. bnorwood

    bnorwood In Third Gear

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    192

    hi Handy Andy. The carb is the 1bbl Holley 1904.
     
  10. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    It's a pretty simple carb to deal with, and I can get you pages to deal with it from my Motor manual. But as I said, you should pull the spark plugs, look to see how they're colored, whitish for lean and black for rich, gloss black is oil-burning.
     
  11. burninbush

    burninbush In Maximum Overdrive

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    Not sure where the fuel filter would be on your car -- but I'd surely change that out with a major-brand filter.
     
  12. bnorwood

    bnorwood In Third Gear

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    192
    Fuel filter is new. Definitely not plugged or restricted.
     
  13. bnorwood

    bnorwood In Third Gear

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    I bought a rebuild kit. Unfortunately, I cleaned all of the plugs (it had mostly been sitting for the last two years, and had not run at all for about 4 years before that). So, since I cleaned them, maybe 100 miles….
     
  14. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    If it's running rich, they'll definitely show it. Lean, not so much.
     
  15. bnorwood

    bnorwood In Third Gear

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    192
    Definitely running rich…

    all of the plugs were like this…powdery black layer that wiped off fairly easily.

    5B0E49FA-0349-4302-932B-018E6769FFE8.jpeg
     
  16. bnorwood

    bnorwood In Third Gear

    Messages:
    192
    Okay, time for an update.

    It seems to me that I have the rich-running problem fixed, but timing still seems kinda wonky to me. I don't necessarily get the kind of ping I remember hearing out of the old 429/2bbl that was in mom's '71 Mercury Marquis, but neither am I getting a full-on backfire.

    What I experience on heavy acceleration is a "pop" sound that is only occasional - and I'm thinking it is still caused by a timing issue. If that's what it is, then it's not good, and I don't want to drive too many miles just testing different settings.

    Following grebaba's response above from 27 July, I tried to set the timing by vacuum at the distributor - only there's a problem with that.

    At idle, I'm showing NO vacuum at all. If I race the engine, I see vacuum.

    Is this a vacuum leak or a plugged orifice at the carb? Either are possible, but I think this is what is causing my issue. I can set the idle at 6° BTDC and it purrs along just fine in the shop - but under load, it just does not seem "right". Runs and drives, but there seems to be a tendency to not run well unless it's choked a bit (this would be consistent with having to artificially increase the vacuum at the carb outlet/intake side of the throttle butterfly, correct?

    There is only one line from the carb to the vacuum advance, and that is brand-new stainless steel, so I didn't really think a vacuum leak could be the culprit, but.....

    Suggestions?

    I'm starting to think the best thing to do is to physically, manually verify TDC on #1, then go from there. But that still wouldn't answer my question about vacuum at idle.
     
  17. pmrphil

    pmrphil In Maximum Overdrive GOLD MEMBER

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    The lack of idle vacuum is correct - it's called ported vacuum - nothing at idle (closed throttle blades) but when throttle is opened vacuum is present. That part is good. When does it pop? Cruising, upon acceleration, slowing down, etc.? Consistent pop (as in steady) or intermittent?
     
  18. bnorwood

    bnorwood In Third Gear

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    192
    The pop is intermittent, but typically upon acceleration (e.g. up a hill).
     
  19. pmrphil

    pmrphil In Maximum Overdrive GOLD MEMBER

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    A pop under acceleration usually indicates a lean misfire. Your statement about it needing to be choked a bit also indicates the same. You might want to investigate a way to put a bit more fuel to it - larger main jet possibly?
     
  20. plumcolr

    plumcolr In Maximum Overdrive SILVER MEMBER

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    Could be float level is a little off as well.
     
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