MP DISTRIBUTOR TIMING CURVE 340
Changes don't do what you think they they will do. In particular changing the advance also changes the initial spring tension and degrees out before the secondary spring joins in.
2 bbl 318 is a pretty efficient engine. Doesn't need that much advance until high rpm.
I'll promote reading up on what timing does, a post from this thread: total timing reading accurate with no load?
Since your timing measurements started with TDC, lets plot them onto a chart with a factory 318 distributor that was meant to be set at TDC. Some others graphed here.
You want the advance to begin at a lower rpm. Then response off the line should have more pep. For your 318, if you want to learn how the adjustments inter-relate, would be worth changing the advance from 14 to 18 or 20. If I remember this right, increasing advance range this will increase tension on the primary spring and also also allow the long loop spring to engage earlier. If you observe inreasing the advance is putting more tension on the primary spring, then you will have to bend the tab in a little. The mechanism already has too much force on it at rest, and this is holding it back from advancing until 1500 rpm. If it has two short loop springs, exchange one for a long loop spring. Make sure the long loop spring is a little loose at rest.
For that an advance curve more like the Chrysler built MP distributors came with, or that Rick works out here.
https://www.forabodiesonly.com/mopar/threads/distributor-curve-help-needed.496183/#post-1973532835
edited since MoparR&D shook my brain
If it looks like this, its a Mallory built version.
Changes don't do what you think they they will do. In particular changing the advance also changes the initial spring tension and degrees out before the secondary spring joins in.
Advance should begin at 1000 rpm or less. Stock, non-smogged 318 should start advancing by 800 rpm.
That's too much timing at 2500 rpm to use with vacuum advance.
2 bbl 318 is a pretty efficient engine. Doesn't need that much advance until high rpm.
I'll promote reading up on what timing does, a post from this thread: total timing reading accurate with no load?
Since your timing measurements started with TDC, lets plot them onto a chart with a factory 318 distributor that was meant to be set at TDC. Some others graphed here.
You want the advance to begin at a lower rpm. Then response off the line should have more pep. For your 318, if you want to learn how the adjustments inter-relate, would be worth changing the advance from 14 to 18 or 20. If I remember this right, increasing advance range this will increase tension on the primary spring and also also allow the long loop spring to engage earlier. If you observe inreasing the advance is putting more tension on the primary spring, then you will have to bend the tab in a little. The mechanism already has too much force on it at rest, and this is holding it back from advancing until 1500 rpm. If it has two short loop springs, exchange one for a long loop spring. Make sure the long loop spring is a little loose at rest.
Good info. Should also test for what vacuum is needed to begin obtaining vacuum advance.
That's fine
For the 340 - No.
For that an advance curve more like the Chrysler built MP distributors came with, or that Rick works out here.
https://www.forabodiesonly.com/mopar/threads/distributor-curve-help-needed.496183/#post-1973532835
edited since MoparR&D shook my brain