robinezrex

hi guys,

i have the 12a 1984 gsl FB, i wan't to run my engine with the static timing since i'm running weber dcoe 45 and i wan't to get rid of the vaccum source for the dizzy... Seem the easier way.

my problem is, i don't know how to lock the vaccum advance on it AND how to use my timing light to set both the trealing and leading ???

i also find that i should keep stock timing number for my engine since i have the stock port 12a

i know it is noob as question but i'm stuck here in my car

can anyone give me the real deal with all that or a link where i can find what i need to know???

would be really really appreciate.

thanks

Joe428

There is two timing advance systems on these cars, mechanical and vacuum.

To disable the vacuum advance you just have to remove the vacuum lines from the diaphragms on the dizzy and plug the other end.

To disable the mechanical advance you can either weld the mechanism or just remove the springs. By removing the springs the dizzy will go to full mechanical advance when running.

Once you disable whatever advance(s) you want you set your timing to whatever you want. There are two marks on the pulley for stock leading and trailing timing at idle. You can also make your own timing marks.

To set the leading timing you put your timing light pickup on the L1 plug wire and adjusthe by rotating the entire dizzy. To adjust the trailing timing you put the pickup on the T1 plug wire and adjust the adjuster on the mount for the trailing vacuum advance diaphragm in or out.

t_g_farrell

iTrader: (1)

So I used to run my Dell without vacuum advance because its at full advance at idle. So I pulled
it off. Idled smoother but didn't accelerate quite as hard. Mechanical was still functioning BTW.

To the point, the best way to set the timing is at about 4K rpm so you are at full mech advance.
You can set it to about 27 deg if I remember right and have the trailing follow at around 17-20.
Should work well whether you use vacuum advance or not. Locking the mech advance is not
really needed or desirable on a stock port running a carb. Its only done on a boosted setup
where you need to be very careful to avoid detontation due to advancing the ignition.

In the end I ran my Dell with vac advance because it behaved much better off idle and I just
accepted the lumpy idle. Run strong and was a great setup for about 20+ years. I now run
a hogged out nikki thats much better all around and even more fun.

rwatson5651

iTrader: (5)

My mileage went way up when I added vacuum advance. Went up from about 16 mpg to about 20 or so.

And, I have always used Farell's method for setting the timing with good results.

robinezrex

nice !

big big thanks, its give me all the information that i was looking for.

by the way, when you use both the mecanical AND the vaccum advance, what was your setup for the vaccum line ?

because, i've done few test and it ended up been like a "Y" fitting to grab those two vaccum connector from the dizzy and send it in the racing beat intake manifold (the closer one to the carb). But to be honest, i'm really not sure it is the good way to connect it...

can you tell me how you plug those vacc on your car ?

thanks

t_g_farrell

iTrader: (1)

I took a tee off the vacuum intake on the dell manifold for the brake booster and
fed that over to the dizzy and then split into a Y to attach to both advance actuators.