Register now to get rid of these ads!

Not another SBC question!?

Discussion in 'The Hokey Ass Message Board' started by rgrhoward, Feb 4, 2013.

  1. rgrhoward
    Joined: May 20, 2010
    Posts: 176

    rgrhoward
    Member
    from Tacoma, WA

    Having a little trouble with my 68' 327 SBC. Brand new rebuild and my first. Around 1,500 miles and i just re adjusted the valves while running. for some reason she doesn't want to start again after she is warm. I mean she starts but it is a challenge. Well that was until today, now she starts hard all the time. Here is what i have gathered so far with the timing light and the vacuum gauge.

    800 RPM at idle
    18.5 HG Vacuum (tiny drift- less that 1/4 HG)
    10 Degrees Advanced Timing
    Mild cam.

    What am i missing?

    Oh and a mini high torque starter or gear reduction.
     
  2. big duece
    Joined: Jul 28, 2008
    Posts: 6,109

    big duece
    Member
    from kansas

    How were the valves adjusted while running? Maybe too tight? Did you do the zero lash and 1/2 turn?
     
  3. rgrhoward
    Joined: May 20, 2010
    Posts: 176

    rgrhoward
    Member
    from Tacoma, WA

    Backed them off until they just chattered, tightened just until it quit and then went 1/2 turn.
     
  4. 327Eric
    Joined: May 9, 2008
    Posts: 1,515

    327Eric
    Member
    from Diablo Ca.

    did you just do a swap, add headers? it sounds like solenoid heat soak. Do you have a good ground, and good clean connections for your starter. The additional heat of the tight engine could be causing this. I have run into it many times.
     

  5. big duece
    Joined: Jul 28, 2008
    Posts: 6,109

    big duece
    Member
    from kansas

    Does is spin over slow, like under a load or spin quickly?
     
  6. rgrhoward
    Joined: May 20, 2010
    Posts: 176

    rgrhoward
    Member
    from Tacoma, WA

    No swap everything is new. I am running tight fit headers, that ole' IHC frame is narrow! I was redundant on grounds when i wired but i will check them. I did have to put some heat wrap around my starter wires because i noticed they were getting worn from heat. If it is heat soak, what is my fix?
     
  7. rgrhoward
    Joined: May 20, 2010
    Posts: 176

    rgrhoward
    Member
    from Tacoma, WA

    Spins quick.
     
  8. A new heavy gauge wire from your ignition switch to your starter solonoid will probably fix your hot start problem.
     
  9. Cancel that. Spins quick..... back off the valves and start fresh.
     
  10. rgrhoward
    Joined: May 20, 2010
    Posts: 176

    rgrhoward
    Member
    from Tacoma, WA

    Do you normally adjust your valves running? or cold? I hear pros and cons about both, last time i did them running but i will not say it was a great experience.
     
  11. unkledaddy
    Joined: Jul 21, 2006
    Posts: 2,865

    unkledaddy
    Member

    You seem to have developed the problem since adjusting the valves running. Why not try adjusting them not running/cold and see if that makes a difference?
     
  12. belair
    Joined: Jul 10, 2006
    Posts: 8,605

    belair
    Member

    Re-do the valve adjustment-tighten the valve untilthe rocker arm quits clacking, then 1/2 turn. You said you tightened them until the engine quit and then went another 1/2 turn. I bet you have some too tight.
     
    Last edited: Feb 5, 2013
  13. are the valve springs new?
     
  14. FANTASY FACTORY
    Joined: Mar 6, 2008
    Posts: 256

    FANTASY FACTORY
    Member

    LEMMINGS... You said valves, so every body says valves.
    Coincidences do happen, check the choke.
     
  15. Standard gas&oil
    Joined: Dec 3, 2010
    Posts: 289

    Standard gas&oil
    Member
    from USA #1

    Make sure your carb floats are correct. Sounds like its flooding if it cranks/spins fast and is hard to start. Does it blow out black smoke when it fires up?
     
  16. Running a Q-jet carb? If so, they are famous for having leaky well plugs in the bottom of the carbs float bowls....will drip gas into the intake after shutting engine off, flooding it.
     
  17. Yep. ^^^ If hard start came after valve adjustment then valve lash is your most likely culprit.
     
  18. belair
    Joined: Jul 10, 2006
    Posts: 8,605

    belair
    Member

    That's what all us lemmings think^^^
     
  19. Or you knocked something loose while farting around with the valve covers.
    Or coincidence on ignition related problems

    Remember, whenever a new problem arises, always go back to the last things you fixed. Retrace you steps
     
  20. I'm just glad to hear that you've got a vacuum gauge! :D

    If you don't find a fuel or electrical problem, see what kind of cranking vacuum it will pull. Ignition off, throttle plates completely closed (back off idle speed screw) and close off any vacuum lines to the intake. Should pull maybe something like 5 to 7 inches when cranking.
     
  21. unkledaddy
    Joined: Jul 21, 2006
    Posts: 2,865

    unkledaddy
    Member

    I think the OP meant rocker arm quit clacking............not the engine.
     
  22. Where's it say " until the engine quit " ? I added the red
     
  23. belair
    Joined: Jul 10, 2006
    Posts: 8,605

    belair
    Member

    You're a good proofer. I misread it because I thought "it" meant the engine and not "the chattering". My error, but I still wonder what "it" is.
     
  24. mashed
    Joined: Oct 15, 2011
    Posts: 1,474

    mashed
    Member
    from 4077th

    Just for the halibut retard the timing a little and see what happens.
     
  25. rgrhoward
    Joined: May 20, 2010
    Posts: 176

    rgrhoward
    Member
    from Tacoma, WA

    Ok, readjusted valves, checked starter for excess heat, re-tuned the Edelbrock 600, retarded the timing to 8 degrees. Going to let it cool down and give her a shot.
     
  26. rgrhoward
    Joined: May 20, 2010
    Posts: 176

    rgrhoward
    Member
    from Tacoma, WA

    Floats in the Edelbrock 600 were a little off, adjusted them. Re adjusted the air/fuel, timing back to 10 Degrees advanced. Truck pulls a solid steady 19HG at 850 RPM idle. Runs great.

    Thank you for all the info fellas.
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.