distributor advance

[Sweet_Johnny]

option a is what i did 10 base 24 mechanical 20 vacuum .option b is 5 base 27 mechanical 20 vacuum option c would be 14 base i have weights that give 16 mechanical and 20 vacuum i don;t know if starting the engine would be a problem with 14 base and i don;t know which option would be better .it;s a lot more complcated than i originally thought.. being retired is great i have time to play and it was fun putting that engine and trans in last summer

I'm a fan of Option C and have had more than one engine with that much base advance without starter kickback. I've only run into that with more than 20° of base. Every engine is different but I see no reason not to try Option C at least once. You'll find there's a lot going on with fuel and ignition systems and everything is more complicated than it seems. I'm reminded of that regularly lol.

 

[Ernest]

If you want to use a good amount of initial advance without worrying about having too much mechanical advance in conjuction of limiting the vacuum advance, tap the advance plate hole for threads, use a small head screw, shave down one side the head flat little by little till you get the mechanical advance you want, its tedious, but it should net you the results you want. I've also seen people use a roll pin, the same used for securing the distributor gear to the shaft, not sure how much that nets with less degrees because of its small diameter, but im sure its a lot less than what you have now. GL

 

[doood]

When you consider the so called vacuum advance part it's more of a devance (retard) as it spends a lot of time retracting from the default advance...somebody needs to make a circuit that works with a map sensor and drives a dedicated servo too, lol...

Are you being funny about upgrading to use something at least as modern as the GM CCC and ECU?

I do see that the vacuum canister on the advance is quite slow.

 

[Rt Jam]

If you want to use a good amount of initial advance without worrying about having too much mechanical advance in conjuction of limiting the vacuum advance, tap the advance plate hole for threads, use a small head screw, shave down one side the head flat little by little till you get the mechanical advance you want, its tedious, but it should net you the results you want. I've also seen people use a roll pin, the same used for securing the distributor gear to the shaft, not sure how much that nets with less degrees because of its small diameter, but im sure its a lot less than what you have now. GL

I would put 2 screws. That thing spins at 3 or 4 thousand revolutions per minutes. Balance is important.

As for big numbers with manifold vacuum advance. That is the goal and it will disappear under load.

 

[Ernest]

No need for two screws when it comes to balance concerns, only one is needed.... its placed towards the center of the shaft where there really isnt any issue, there are nylon scews that can also be used, easier to modify IMO, but im not sure how it will hold up to the heat inside the destributor.

I thought about doing this same mod with my mechnical distributor, that was until i came across the progression ignition unit thats totally electronic, no weights or springs, not even a vacuum can to mess with, all done by bluetooth via smart phone or tablet, adjust on the fly or sitting in park/neutral while idleing.

 

[jcelk]

i;m getting it theoretically i;ll have the most power if i lock out the advance at 36 deg but that will make it ping and impossible to start so i have to have less than 36 deg initial and make up the difference with the mechanical weights to get 36 deg when i am in my power band it;s trail and error to find the sweet spot .that a great idea with the screws in the advance plate ..i;ll be messing with that in warm weather.. thanks guys and have a good christmas