Mild 318 pinging
Distributor still ahve its tag? It should match the number in the book.
If so, then you can get a ballpark whether yours is in spec and the shape of the curve above 2000 rpm.
Plot your engine mechanical advance vs. the advance max and min from the book.
The factory initial was basically TDC (at 700 rpm? ) and now its at 11* BTDC at maybe 700 rpm?
If so, then that's probably the crux of the problem.
Will it idle at 5 or 6* ? If so that may be a quick solution, or partial solution.
With less initial, then if it wants a bit more timing at idle - if the manifold vacuum at idle is reasonably stable - try using manifold vacuum source for the distributor's vacuum advance.
With the 4 bbl and the cam, probably should reshape the timing curve but those two steps may get you driving for now. Plot the timing first to make sure the assumptions here are true. Also this
It should not ping at part throttle with the vacuum advance disconnected.
It may ping near full throttle, and that would indicated too much timing at the rpm.
Notice the factory gave 4* leeway in the initial. This was to allow for different fuel, altitude and owner preferences. My folks had their '69 318 advanced a little and ran Premium until the gas crisis. 21 mpg on the highway. Pretty good at the time for a v-8 in a midsize car with an auto transmission and bias ply tires.
Distributor still ahve its tag? It should match the number in the book.
If so, then you can get a ballpark whether yours is in spec and the shape of the curve above 2000 rpm.
Plot your engine mechanical advance vs. the advance max and min from the book.
The factory initial was basically TDC (at 700 rpm? ) and now its at 11* BTDC at maybe 700 rpm?
If so, then that's probably the crux of the problem.
Will it idle at 5 or 6* ? If so that may be a quick solution, or partial solution.
With less initial, then if it wants a bit more timing at idle - if the manifold vacuum at idle is reasonably stable - try using manifold vacuum source for the distributor's vacuum advance.
With the 4 bbl and the cam, probably should reshape the timing curve but those two steps may get you driving for now. Plot the timing first to make sure the assumptions here are true. Also this
is a good check too.
It should not ping at part throttle with the vacuum advance disconnected.
It may ping near full throttle, and that would indicated too much timing at the rpm.
Notice the factory gave 4* leeway in the initial. This was to allow for different fuel, altitude and owner preferences. My folks had their '69 318 advanced a little and ran Premium until the gas crisis. 21 mpg on the highway. Pretty good at the time for a v-8 in a midsize car with an auto transmission and bias ply tires.
