SBC Timing Problem

[street3285]

Ok, I will double check timing and make sure the wires are correct in the cap at TDC. When I do get the engine revved up, by slowing giving it gas, it does run smooth. Just any quick kicks of the throttle or anything, and it wants to die.

I will take a video of it when I get a chance next. Appreciate the help so far.

[GregWeld]

Travis -

Is your vacuum advance hooked up? If so to which port on the carb? You'll most likely want it to the PORTED vacuum not the manifold vacuum.... ported will have NO vacuum at idle. Manifold will have vacuum at idle.

I'll also ASSume that you timed it at around 12 or 14* INITIAL timing - with NO VAC ADVANCE - that the vac advance was disconnected and the port on the carb was plugged. ALSO if you have a dial back light -- make a map of your timing advance curve. You let the car idle to get the "initial" - then hold another 500 rpms on the engine and check timing - add another 500 rpms and write that down etc. Until you see no more MECHANICAL ADVANCE.... do all of this with the vacuum advance disconnected and plugged. Mapping this will tell us the CURVE in your distributor. You'll need a dial back light to make this easy... as you'll just dial back to zero on the balancer and then read the timing in the light.

Also -- give us the vacuum readings the motor makes. Have you adjusted the idle screws (on the carb) to give you highest vacuum and highest rpms?

[Shaker455]

Travis,
What carb & # number you running?

What dist? MSD?

Where is you initinal & total set.

Do the springs allow the advance to move off idle?

If you are running a Holley and had backfires you may need to replace the Powervalve.
Jeff

[street3285]

I had the chance to work on it a little yesterday. I started with pulling the vacuum advance and re-timing it to 14 initial. I think plugged the vacuum line going to the distributor, so right now, there is no vacuum advance.

The truck runs 10x better. It starts up, doesn't stutter and pop. Just a slight hesitation, but that might be able to be fixed though some jetting.

I will look and get the numbers off the carb and distributor. Thanks for all the help guys.

[GregWeld]

Travis --

Don't mess with the fueling until you are certain you have the timing issues worked out.

You still need to map the curve so you know what you have. There still could be either too much or too little curve - which needs to be worked out.

Once that is "good" --- then the fueling can be addressed. Get one issue at a time sorted...