Re: IML: Electronic Ignition

[sosmi@xxxxxxxxxxx]

Geoff, You didn't say what carb you're using, but if it's the standard Holley increasing main jet size 2-steps richer, and possibly changing the power valve to a 7.5" could do it. You can also buy the adjustable vacuum advance unit, and install it on your existing distributor (and adjust as needed). Engine temp should also be in the 170-180 range. Excessive carbon deposits in the cylinders can also be a problem, but I don't think that's it, since you've had the heads off and probably cleaned pistons, and chambers. There also is a thicker head gasket, that lowers the compression about .5- 1 compression point. Last thing, use the old spec spark plug. Ya'll have a nice day, Dave.

 

> -------------- Original message -------------- 
> From: "Geoff Fors" <wb6nvh@xxxxxxxx> 
>
> > One of the reasons I was thinking about converting to electronic ignition on 
> > my '67 is that the Mopar Direct-Connection style electronic ignition 
> > conversion kit has an adjustable vacuum advance. I have a terrible time 
> > with pre-detonation (pinging) even with supreme brand gasoline and retarding 
> > the timing isn't a very satisfactory solution, particularly considering how 
> > far it has to be retarded. I have tentatively determined that the pinging 
> > is caused by the vacuum advance curve being too aggressive for today's fuel. 
> > 
> > I have already converted the heads to unleaded and don't want to replace 
> > pistons and head gaskets in a project to lower the compression, so I am 
> > looking at distributor advance solutions. > 
> > What have others done regarding the predetonation issue? 
> > 
> > Geoff 
> > Monterey CA 
> > 
> > 
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