Re: IML: Electronic Ignition

[spicemanii@xxxxxxx]

You should be able to do the same with the points distributor I thought. It is an allen screw inside the opening of the vacuum chamber where the vacuum hose fits. That is only on light to partial throttle anyway, not full throttle. The other problem with points is, as you drive, they slowly start to close as they were out the fiber material on the lobes. 
   What I used to do before electronic ignitions was to set the gap about .001 to .002 more openng and or about 1 to 2 degrees of retard, so as you drove, the car would get better than be at the peak of performance when tuneup was first done. This way, as the timing advances as the points get closer and closer, it does not start to ping because of this. It goes into tune instead of out of tune. It also last longer on a tuneup. 
   Champion plugs, for example, used to have a much greater range of heat range choices. Now, it is almost one size fits all. You used to be able to pick a cooler plug for summer, and a hotter for winter. I live where I use a step or 2 because we drive all year with low humidity and warm or extremely hot weather. If you are driving an Imperial with closed chamber heads and with the gas today, yes, pinging is always going to be there. 68 and newer heads drop that compression about .4  points. To about 9.7 compression. That was automatically done on 1970 cars. I have a 1975 open chamber head on my 61 Imperial LeBaron. Zero pinging and as mentioned in past emails, I tow a 10,000 lb trailer all over the country nd have the air on in the summer. There will be a lot of other opinions and mine is not an opinion, as it is the real world I drive in, all year, not just winters. Jetting and other things also come into play. It is not just one simple thing for the cure. If you go to electronic ignition from points and change not
hing else, it could very well still ping. Also, a much larger radiator or make sure it is not plugged or partially plugged. Here is a piece of info, I know will cause a stir. The cooling systems on older cars is way out in left field. They should be run in reverse. Get the coolant to the heads first, then to the cylinders. You would be able to have a hiher compression if this was done. Newer cars are this way and they also have a sensor that decects a ping and automatically retards the timing. Oh well. Can do only so much with what we drive. joe machado


-----Original Message-----
From: Geoff Fors <wb6nvh@xxxxxxxx>
To: mailing-list@xxxxxxxxxxxxxxxx
Sent: Tue, 9 Oct 2007 7:22 pm
Subject: IML: Electronic Ignition

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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