In the Mopar Book on Six Cylinders it talks about Optimum Performance tuning. You set the mechanical advance timing to 32 degrees and set mechanical/vacuum total to 52 degrees. I haven't tried these settings on my D-150 truck because my distributor curve doesn't look like that will work out. I am running at 12 BTDC initial timing. Should I attempt to use the timing from the Mopar Six Cylinder book, or is there a better way to determine the optimum tuning?

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'72 Duster (Performance 360)
'83 Ramcharger (Performance 318)
'80 TrailDuster (360)
'80 D-150 Truck (See Below)
CompCams 252S, Holley 390cfm, Offy manifold
Ported, Polished and Gasket Matched
P4286813 Springs,0.040 Overbore,
0.090 Shaved Head

Define "better." If you want a relatively quick way to find a good timing setting, asking people who have tested a similar combination to yours what they are running will get you in the ballpark. No timing setting will be correct for all engine builds and applications - the timing for a stock motor, a low compression turbo engine, and a naturally aspirated race motor on alchohol will all be very different.

If you want the timing settings that extract the most horsepower possible from your engine, you're going to have to put it on a dyno and repeatedly try different settings. If dyno time is too expensive, you can take it to a dragstrip and play around with different settings to see which gives you the highest trap speed.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

If you look back on most of the old posts, you'll find for drag cars the MP distributor is max of 30 degrees (mech + initial)....with 50 total if vaccuum adv is hooked up...

In my heavy duster I ran the 32/52 and it got good mileage at highway cruise, but had a real tendency to ping... I think 52 would be good if the land was flat and an EGR was put into play...

I would think that you might get away with the 12 init/18 mech/20 vacc... if you apply a heavier adv. spring due to the weight of the truck and how your build is...

You'll need to make dyno run, or like me, you find a nice 'test track' with flats hills/etc... install a tach and vacc. guage, bring a friend and take notes on what worked/when it pinged then make changes and try it again...

The sad part is you need to see what governor you have in your dist... setting it to 12 btdc and having a 15R governor isn't pleasant (12+30=42 mech total + vacc= too much+ping)...grab a couple of spares and keep your stock one as a baseline and cobble up one of the others...

good luck on the experiment,

-D.Idiot

When I opened my distributor for inspection I think I noticed it had a 15R governor. I read in the messages comments about detonation and pinging. Is detonation caused by retarded timing and pinging caused by advanced timing? Or are they the same thing?

If I push on the accelerator hard it should ping or just barely ping or no ping at all? How will I know if it is detonating? I think I know what pinging sounds like.

Thanks in advance.

bwhitejr

_________________
'72 Duster (Performance 360)
'83 Ramcharger (Performance 318)
'80 TrailDuster (360)
'80 D-150 Truck (See Below)
CompCams 252S, Holley 390cfm, Offy manifold
Ported, Polished and Gasket Matched
P4286813 Springs,0.040 Overbore,
0.090 Shaved Head

Detonation and pinging are pretty much the same thing. Neither one is acceptable. Too much timing advance is the most common cause of it, but there are a couple other possible causes, from an air/fuel ratio that's too lean to some types of carbon deposit issues. In many case, though, backing off the timing can reduce detonation even when you have other problems. There are limits, though - no amount of backing off the timing will cover the problems you might get if you were running 14:1 compression, a 18:1 air/fuel ratio, and 85 octane gas.

_________________
"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair