Tundrarules, the first red flag for me with the Pertronix information, is the distributor shown in the illustration.
Take a look for yourself.
http://www.pertronix.com/support/manuals/pdf/billet.pdf
If this was truly Marine information, they would not be showing an automotive ignition distributor!
I think that they would be illustrating a Marine Ignition Distributor.
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I don't know if I mentioned this in this thread, but the High Performance auto engine passes through the most critical RPM range (the range where detonation may be a greater risk) rather quickly. Whereas our Marine engines may sustain this RPM for a longer duration.
Wrong curve, wrong TA at the wrong RPM, and Bingo....... possible detonation!
I could easily make some SBC suggestions for you, but I'm not confident that the 318/360 requires the same curve and/or TA.
I do know that:
No marine engine is going to like anything more than BASE or Initial advance at idle.
No marine engine requires any mechanical advance (or EST influence) prior to 1k RPM.
There's simply no need for it.
In the info shown below:
The numbers here are goofy to me.
It's easy enough to convert the distributor RPM into Crank RPM..... that's not the issue.
The issue is when you plot this out in graph form.
Let me explain that:
Note the key words
"Distributor Degrees at Distributor RPM".
Distributor turns one half crankshaft RPM... or 2 crankshaft revolutions per 1 distributor revolution.
1 distributor degree = 2 crankshaft degrees.... or 2 crankshaft degrees is 1 distributor degree.
In my world, ignition timing has always been done at Crankshaft angle.... not distributor angle.
If we take that information literally, here's what you have.
Chrysler specs in Blue text.
Actual crankshaft data = 2 x's distributor degrees and distributor RPM in Brown text.
First set of numbers:
0* @ 275 to 425 =
0* crankshaft angle @ 550 to 850 crankshaft RPM....... If this is minus BASE advance, this is reasonable.
0* to 7.5* @ 425 =
0* to 15* crankshaft angle @ 850 crankshaft RPM........ Add BASE of 5*, you have a potential of 20* @ 850 RPM. This is not reasonable.
6* to 8* @ 550 =
12* to 16* crankshaft angle @ 1,100 crankshaft RPM....... Add BASE of 5*, and again, this in not even close.
12* to 16* @ 1,100 RPM and we have not yet added BASE..... ???
Let's look at the second set of numbers:
0* to 2.5* @ 450 =
0* to 5* crankshaft angle @ 550 to 850 crankshaft RPM..... If this is minus BASE advance, this is over the recommended 5* BASE.
5* to 7* @ 600 =
10* to 14* crankshaft angle @ 1,200 crankshaft RPM...... This is a huge jump in just 200 to 400 RPM and we haven't even considered BASE.
8* to 10* @ 700 =
16* to 20* crankshaft angle @ 1,400 crankshaft RPM...... That's a 2* to 4* jump in just 200 RPM and again, we haven't even considered BASE.
11* to 13* @ 1600 =
22* to 26* crankshaft angle @ 3,200 crankshaft RPM....... Add a BASE of 5*, and this becomes 31*.
31* may be realistic for the a Good Quench Built SBC.... just not sure about the Chrysler 318/360.
13* to 15* @ 2200 =
26* to 30* crankshaft angle @ 4,400 crankshaft RPM........ Again, add a BASE of 5*, and this becomes 35* @ 4.4k RPM.
At 4.4k RPM, we're likely over the OEM WOT RPM.
At even near 4.4k RPM, we should be well up on plane where engine loads should be reduced some.
However, seldom do we see progressive Marine Cruiser engine curves ranging up to 4.4K RPM.
My limited Chrysler Marine experience conclusion:
In spite of this info, we still have a mystery on our hands!
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