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.
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.
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?
A new heavy gauge wire from your ignition switch to your starter solonoid will probably fix your hot start problem.
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.
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?
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.
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?
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.
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
I'm just glad to hear that you've got a vacuum gauge! 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.
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.
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.
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.
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