The Stovebolt Site Forums The Shop Area Engine Shop 216 octane advance degrees

Hey gang,

Just did some routine clean up on my 53. Plugs, cap, rotor, wires, new gaskets on the oil pan, pushrod cover, and valve cover, hoses, and fluids. Interestingly, the trans was leaking too from the fill plug so I changed that fluid with only a half cup of fluid coming out, so really, it wasn’t a fluid change more of an addition!

So with the ignition, I was reading about the octane gauge (if you call it that) on the distributor base. Mine is set to 0. The truck runs great, but there is a noticeable cough when giving the gas, so I figured a little ignition advance was in order. Would this adjustment give me a few degrees advance that I desire? Pretty neat that there’s a little gauge there.

Cheers
Dave

Unless your timing is way off, slight timing variance won't generally cause a "cough".
If a timing light indicates that the ball is on the needle and your octane selector is set at zero, you should have 5 degrees advance which is called for on a 216.
What carburetor do you have and how would you describe its current condition? Recently rebuilt, properly adjusted?
You didn't mention anything about your points. Dirty points make for a weak spark. Will that cause a cough? Maybe. It's something which requires checking and maintaining regardless.
Bottom line is, I wouldn't start with adjusting the timing away from factory setting of 5 degrees BTC in an attempt to chase down a cough.

Thanks, Carl. Points are new and adjusted. Carb is probably in need of a rebuild and may be the source of the stumble. It’s well used, but seems to run well. Haven’t checked the accel pump yet. I’ll dive more into it tomorrow.

Edit; I see you added more info. Agreed, and I’ll check that tomorrow too (ball and pointer). Was just throwing out some questions this evening. I do disagree that bad timing will cause a stumble. Fixed that in many a car.

Does it cough as soon as you give it gas? If so, might be accelerator pump. A cough is usually fuel related, but can be caused by a sticky advance. Check advance weight springs and pivots, and check for vacuum advance leaks; especially if the cough occurs a bit after giving it gas.

Yes, incorrect timing can cause a "stumble". You originally indicated that you had a "cough". So now I do not know what you have.
In any case, it is much easier to double check the timing than it is to rebuild a carburetor.
It may well be that your carburetor needs some attention, but it is always best to check everything else before you move on to the carburetor.