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No Power In Second Gear, Under Load..????

Discussion in 'Early CJ5 and CJ6 Tech' started by 1928 Chevy CJ5, Mar 6, 2021.

  1. old pappy........... I did re-time it, After I pulled the distributor and moved it forward one position to the next odd lobe..... And I had it timed at 0 TDC.... but before, I had it timed at 10 TDC......... After timing it with the vacuum hose plugged... when I hooked up the vacuum hose to the distributor the vacuum can bakes a whistling noise....??? perhap the vacuum can is my problem.... Where can I order a Prestolite Vacuum canister...?
     
  2. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Unlikely you will find a Prestolite advance can by itself. You sure it's Prestolite and not Delco? A complete reman will probably include a rebuilt (not new) advance can.
    1970 JEEP CJ5 3.7L 225cid V6 Distributor | RockAuto

    Put a hose on the nipple and suck on it. If it passes air, it's kaput. Should hold vacuum. A MityVac is a good tool to test these.
     
  3. 45es

    45es Active Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    If heading down this path, wouldn't an HEI be a better consideration? All new parts and better ignition.
     
  4. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Aftermarket? No data from me. Both the Delco points ('68 CJ or '64 Buick Skylark) and Delco HEI ('77 Buick Skylark) odd-fire distributors on RockAuto are rebuild-your-core only.
     
  5. Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    A whistling vacuum can seems to be an important clue, that or the mechanical advance not doing their job, can certainly cause the symptoms described.

    I bought a HEI for my V6 but it is an even fire 231, I am not sure you can find one for the Odd Fire, but if so that is what I would probably do.

    Nothing wrong with a points distributor if it is in good working order.
     
  6. UPDATE..... I pulled out the distributor again..... and on top of the center shaft cam, I painted red where the long cam lobes are, that hold the points open longer and then I re-installed it..... so that at 0 TDC ..... The points were just opening on a short duration lobe, when the rotor was on # 1 cylinder....... the wires are on the cap, in the right firing order 1-6-5-4-3-2 ..... I set the point gap at .016 (by the manual for a prestolite)
    I also opened up the nut on the vac can (nipple end)..... and pulled out the three washers and spring and noticed that the threaded nipple cap had no O ring/rubber gasket above the threads..... so I happened to have one just the right size... put it all back together, and sucked on the nipple and it would pass NO AIR and held my suction...... re- installed every thing, warmed it up, plugged off the vacuum line to the carb/dist............. started it right up.... and advanced the timing to + 12 degrees (with a timing light at 750 RPM)....... then, with the vacuum hose hoked back up to the Distributor & carb base........ No more vacuum whistle..... great! vac can is good....... it revved up nice and smooth to about 4,000 RPM......... got in to drive it, in 1st gear it bogs down as I accelerate fast.... but accelerates smooth is given gas slowly.......... total bog down if I put it in second at any speed.... no acceleration in 2nd.... it actually starts to die. I think the timing is right now.... I will get a vacuum gauge, clear fuel filter and a coil, this Wednesday......:banghead: :whistle: :)
    I want to keep the simple points distributor..... because they do not get knocked out if we have a large solar flare activity, like electronic ignition and computers do........
     
  7. ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Get a spare condenser or two while you’re there.
     
  8. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    So...

    Your symptoms as described indicate it will rev, but bogs under load. Go from there.

    Vacuum leak, or badly gapped spark plugs can do this, but first of all are your ignition points definitely clean and properly gapped?
     
  9. ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    This part. What does it sound like? Any popping through the carb/exhaust? Is it a smooth transition to no-fire, or does it buck with intermittent firing?
     
  10. Petel.... The points are CLEAN and set at .016 ( by the manual for the prestolite) Spark plugs are clean and gaped according to Manual.......... I will be checking for vacuum leak when I buy some carb cleaner. ITLKSEZ............ When it starts to die there is no popping or backfire or bucking.... it just acts like I am Not giving it any gas..... the engine slows down as I increase the gas... bogs down... then when I take it out of gear the engine slowly revs up again.......... no bucking, no noise..
     
  11. jpflat2a

    jpflat2a what's that noise?

    Check for shop rag down the throat of the carb...don't laugh...BTDT.
     
  12. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    "when I take it out of gear the engine slowly revs"

    Over-rich/flooding under load?
     
  13. ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    It sure sounds electrical to me.

    You can try pulling a plug out, grounding it to the head/block, run and rev the engine, and watch the spark. You’ll be able to tell if it’s strong or weak. It should be a bright blue/white thick spark. If it’s wire-thin or orange, it might not be getting a strong enough spark. The coil might not be re-energizing quickly enough at any speeds above idle.

    What’s the age/condition of the condenser? There has been a boatload of bad condensers within the last decade or so.
     
  14. ITLKSEZ......... The condenser and plug wires, coil etc are old... it sat in storage un-run for 10 years before I got it........... I read on another site that the prestolite advance components have problems after setting..... quote;
    The Prestolite distributor works, but isn't really a good choice. They tend to have excessive dwell variations. And since the mechanical weights are under the plate they never get maintenance attention and freeze up, thus eliminating advance.
    With a delco I have the dwell set at 29 and timed at 8 BTDC. None of the prestolite hesitation during acceleration and it runs like new.
     
    Last edited: Mar 8, 2021
  15. Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    I noted in a private message to 1928 Chevy CJ5 I had similar symptoms last year on the Colorado epic when the fuel pump was on it's way out. It was pumping some fuel, but not enough for sustained load. It would quietly want to die out climbing the pass. If you pulled over and let it idle for a bit it to fill the fuel bowl, it would go another few blocks.

    Worried that there weren't enough safe pullouts to get me over the pass, I pulled the gas cap, used duct tape to seal an extra chunk of hose to the tank, and blew in to hose to pressurize the tank. That got me to the top of the pass so I could coast down the other side to the rental.

    Swapping in a new Delphi pump at home fixed it immediately.

    Temporarily bypassing the mechanical pump with an electric one would be one way to test.
     
    47v6, SIDSCJ, Dandy and 2 others like this.
  16. SIDSCJ

    SIDSCJ Jeep addict

    Went thru that last year on my Cutlass.
    Started fine, idled fine, drove fine UNTIL you got to a hill and had to give it more fuel.
    Would just lay down, slow down, and if you kept your foot in it it would die.
    New fuel pump and off to the races, old one was only 42 years old...
     
    Fireball likes this.
  17. I will get a new fuel pump on wednesday , and checking the strength of my spark today........ replacing and checking so many possibilities..... I am sure to find the problem :)
     
    Last edited: Mar 9, 2021
    ITLKSEZ likes this.
  18. Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    good idea.
     
    PeteL likes this.
  19. anyone know where I can buy a rebuilt or NOS Delco distributor ...???
     
  20. 73 cj5

    73 cj5 Not ready for the junkyard yet

    I went through this with my fhead. It would rev fine but bogged while under load driving. I replaced the coil, distributor, plugs, and wires. It ended up being an air filter restriction.