Timing on a street car??
11-22-2009, 11:35 PM
#1
Instructor
Thread Starter
Timing on a street car??
I have an '81 Corvette with a mild 383/200r4 combo. It has a MSD 6al, blaster 2 coil and Pro-Billet distributor. What is a good starting point as far as mechanical advance (weights & springs)? Base time? Total timing? I'm used to crank-triggers and locked timing so this mechanical advance stuff is new territory to me. Thanks.
11-23-2009, 02:11 AM
#2
Drifting
Member Since: Apr 2006
Location: gold coast queensland
Posts: 1,911
Likes: 0
Received 2 Likes
on
2 Posts
stock motors are happiest with about 10-12 initial
grumpy worked motors normally like about 16-22 initial
so........
you want as much initial as you can get with your type of motor as im assuming your mild is more at the wild end of mild. use your biggest stop bushing from your msd which i think from memory is the black one which limits at about 18 degrees. In turn this means set your initial on your balancer at about 18 giving you a total of 36. this should be close to where you want to be + or - a few degrees of tuning maybe depending on your cam,compression, etc etc, then its up to you if you want to run vacum advance as well.
as a rule of thumb if your motor is stock or has a small/tight converter then the heavy silver springs work best. if your cam is roudy and likes to rev and you have a larger/looser converter for example 2500 and up then go the lighter springs . this is a trial and error basis. myself i run one of the very light blue with a light silver.
i cant remember if there is instructions on the box on how to change the stop bushings but its not hard, just fiddly, very fiddly and when changing springs cover your open carb ..those things love carb-diving.
grumpy worked motors normally like about 16-22 initial
so........
you want as much initial as you can get with your type of motor as im assuming your mild is more at the wild end of mild. use your biggest stop bushing from your msd which i think from memory is the black one which limits at about 18 degrees. In turn this means set your initial on your balancer at about 18 giving you a total of 36. this should be close to where you want to be + or - a few degrees of tuning maybe depending on your cam,compression, etc etc, then its up to you if you want to run vacum advance as well.
as a rule of thumb if your motor is stock or has a small/tight converter then the heavy silver springs work best. if your cam is roudy and likes to rev and you have a larger/looser converter for example 2500 and up then go the lighter springs . this is a trial and error basis. myself i run one of the very light blue with a light silver.
i cant remember if there is instructions on the box on how to change the stop bushings but its not hard, just fiddly, very fiddly and when changing springs cover your open carb ..those things love carb-diving.
Last edited by gingerbreadman1977; 11-23-2009 at 02:19 AM.
