Mild 318 pinging

1973dust said
Yes, that is the tag that is on the distributor.

Great!

1973dust said
I know that I already limited the total mechanical by welding and re-machining
the slots in the advance plate and I know that I got rid of the heavy with long loop spring. I think I replaced it with a 2nd factory light spring which may have been a bad idea.

Well so you've learned the same way I learned. Not so great. The heavy spring was the critical one to keep. A long looped spring with even higher spring rate would be a better match for the 4 bbl and cam. We can plot that out next post.

1973dust said
Am I correct that distributor degrees on the chart have to be doubled to get degrees read at the balancer?

Yes. Also the RPM is doubled as the cam and distibutor run at half the crank rpm.

1973dust said
I have had the initial backed off to 6-8* and it did seem to eliminate most pinging but it seems to handle the in gear drop better with more initial. I'm at a steady 19" at idle in park and a steady 15" at idle in gear at the 11* setting. I'll try driving it without the vacuum advance connected and, if that eliminates the pinging as it should,

That's a strong vacuum for idle and a hot cam. Thats a good thing even though the drop is more than I'd like to see. What rpm in P and D?

1973dust said
I'll try backing the initial off and connecting to manifold vacuum and see where I'm at. If that works, maybe I can avoid having to mess with the advance slots again.

Well we can plot out where its at (the advance) and see if it makes sense. 15" in D can add anywhere from 19 to 25 degrees at idle. That's way more than needed - it may work but wont be the most effecient in terms of power and economy.