Re: IML: Electronic Ignition

[sosmi@xxxxxxxxxxx]

Geoff, by using the AV-Gas you change two things. One is you raised the detonation pressure and temperature, and the mixture is en-riched, more real fuel and less junk. Since the carb is due for replacement, remove the metering rods, and springs. You can stretch the springs about a 1/4" this will en-richen the mixture some more at high manifold vacuum. You can also polish the metering rods down in diameter some. If the rods have defined steps at the different diameters, polish the steps to a more gradual change.  No question, ignition can be the, or only part of the problem. Ya'll have a nice day, Dave.

 

> -------------- Original message -------------- 
> From: "Geoff Fors" <wb6nvh@xxxxxxxx> 
>
> > I guess I should have given more information about my question. 
> > 
> > The pinging I am referring to is at light load with part throttle after the 
> > engine is warmed up. It probably pings at full throttle under heavy load as 
> > well but that's a driving condition I rarely if ever encounter. 
> > 
> > My idea with the electronic ignition was that the vacuum advance was 
> > adjustable. The vacuum advance on my stock distributor is not adjustable in 
> > the same way, at least as far as I can tell, but that's a good point and 
> > I'll examine it more carefully. It's a Standard-Blue Streak replacement and 
> > I never checked to see if the original Mopar one was adjustable. The OEM 
> > kit electronic ignition vacuum advance has an allen wre
> nch-adjustable setup. 
> > There is no pre-detonation with the present vacuum advance disconnected. 
> > Nor is there any with some 100LL aviation gas mixed into the tank, but 
> > that's not a practical solution. That's also a good point about the 
> > mechanical advance, I'll have to chart the curves and do some experimenting. 
> > 
> > This is a stock 1967 setup. The timing chain and sprockets are new. The 
> > heads are completely re-done with hardened seats and new exhaust valves. 
> > Nothing was done at the time to alter the compression ratio and in fact, the 
> > usual surfacing of the heads in the rebuild process probably raised it 
> > slightly. There is no carbon in the combustion chambers. The radiator is 
> > freshly rebuilt, with a new core, and the water pump is also new. It does 
> > not overheat. The carburetor is a fairly worn-out original AFB, which is 
> > going to be replaced shortly as it has some unrelated i
> ssues. It could very 
> > well be running lean, I'll check that too. Oh, and yes, the dwell is 
> > correct as is the timing, and the points are new. The plugs are new and 
> > gapped correctly, but as pointed out, it's becoming hard to find other than 
> > a "one size fits all" heat range, so the plug heat range probably isn't 
> > optimum. The heat riser isn't stuck and functions correctly. The exhaust 
> > system is fairly recent and in good shape. 
> > 
> > Geoff 
> > Monterey CA 
> > 
> > 
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