dan filipi":6d6b7ar3 said:
Back in the day I would use the stock timing mark for reference then bump the distributor more advance to squeeze every last bit out of it.
Once it started to crank a bit slow firing against itself I'd back of a hair til I found the sweet spot.
Every time I had to get a smog cert it had to go back to stock setting to pass. Not sure why it had to go back to pass but it dogged the motor.
When I put the 1000 cams in my 1100 I tweaked it the same way, same thing I'm planning to do after modding the stock vac advance.
I like to play.
Advancing the base timing moves the entire event forward. The spark occurs sooner, allowing more time to burn in the cylinder. This increases cylinder heat and pressure. This condition is where NOX (nitrates of oxide) is born. Keeping in mind that as you compress a gas, the temp rises
proportinately. Bring the temperature up to just before it ignites, then add the spark to ignite it at the desired time. With the "early" spark, the mix has more time to burn "inside" the cylinder. As it's burning, the temp and pressure is increasing. Since nothing really "burns"-
RAPID OXIDATION is what's actually taking place. Think of this as chemicals changing form. Given enough pressure, at 2500+ degrees, molecules start to chemically fuse together, forming a poisonous byproduct. (NOX) This is the reason you had to move the base timing back to spec for a smog inspection. As for why it caused it to bog down.... could have been a few things, perhaps being masked by timing advance. On many cars I solved the hesitation tip in by moving the vacuum advance supply hose from ported to manifold source.
I've also seen a lot of Chevy starter nose cones busted as the result of just a little too much advance, causing a kick back during starting.
I really enjoy reading and learning from you guyzez experiments. I'm just offering what I got for the thought process. Hopefully in the end, we'll all understand what and why something made an improvement.
