Tuning

Ignition system and performance tuning.

if your ignition works at all rpms and loads you run the motor at, a different one that costs more won't make any noticeable difference

if you ignition doesn't work at all rpms and loads ...well obviously fixing the issue or a different ignition might

id suggest there would be some gains in a distributor timing....namely recurve/ advance limiting.
to cater for modern fuel. This will allow you to have the same total mechanical advance you engine wants but will allow you to set more initial advance, modern fuel seems to like a bit more than the initial timing specified in the manual

if manuals states 5*BTDC you may find that the car likes 7 or 10 BTDC initial. or more. Mine likes 15.

Any extra added as initial advance needs to be removed from the total mechanical advance.
ideally you get this done at a shop that does distributor work or you dismantle your own, weld or braze up the advance mechanism stop. then use a timing disk or protractor to direct what weld or braze you need to carefully and slowly file off to achieve your aim

and if you are not running the vacuum advance look into hooking it up again


For example standard distributor will add 28 or 29* of advance between 850 rpm and approx 3000 rpm
if your initial is 5* 5* +29* = 34* total at 3000 rpm

if you then set initial to 10 * you only want your distributor advance mechanism to add in 24* otherwise total would be 10+ 29 = 39 total i.e you need to remove 5 * from the total advance you had to get it back to 34*

but its a little more complicated, every 1 degree the advance armature in the distributor adds in is worth 2* when measured at the balancer
so 28* at the balancer is 14 degrees in the distributor advance

so to remove 5 balancer degrees you would need to limit distributor advance by 2.5 degrees


so you weld up the slots a little bit
re build the dizzy
clamp its drive end in a vice
put your timing disk over the rotor shaft
clamp it down
use a piece of wood as a pointer in the cut out in the rotor shaft and point it at 0*
and twist the top of the distributor to swing out the advance weights
if you now have 11.5 degrees as you twist the rotor arm all good
if you don't you need to take it apart again and file off a bit of your weld until you do.

that gets you half way there
i.e the initial advance can be where the motor wants it and you have stopped your distributor adding in so much as to go further than 34 total.

the other half of the equation is tuning how it adds the advance
this is done with the springs.

that's another complication and this is where a man with a distributor machine is helpful

otherwise its a case of weakest springs from a spring set and drive it hard
if it pings change 1 of them for the next strongest
and so on
until it drives without pinging

there are other ways

if you have a specific mopar model of distributor that is supported by the aftermarket you can get limiting disc and spring set which allows you to achieve a range of settings more easily
FBO used to make a kit

once recurved you can start work on the vacuum advance

it can become a bit of a rabbit hole, but the results are eventually a car that is eager off idle
accelerates well
and with the vacuum advance hooked up goes way way further after you lift your foot off the gas.

it will feel like the car just got smaller and easier to drive
and it will run smoother and quieter than it has done previously
fuel economy will be better
the end of exhaust tail pipe will not be black as soot
and anyone on a motorcycle won't be gassed sitting behind you at the stop lights

Dave