T77.... Awesome article!
A couple of things. First is that the car runs on the cool side of the temp gauge although I have not measured the exhaust gas temperature (interesting that it would be COOLER with a detonating motor...).
Next, I absolutely agree with you regarding the relative meaninglessness of the timing value, if it was not definitely measured. The number I quoted came via my builder, whom I assumed to have verified it before he gave it to me. When the opportunity arises, I will verify this and other specifications/settings that were also quoted to me.
As mentioned previously, I have an electromotive ignition set-up which enables me to choose the cumulative advance (or retard) settings, over three separate rpm ranges (400-1,000 "idle", 1,000-3,000 and 3,000-8,000). The advance is added in a linear fashion thru each range, and each ranges advancement begins where the previous one left off and accumulates accordingly. It's accurate, and is less susceptible to mechanical wear and tear etc. which in turn minimizes the need for re-adjustment.
Anyway, this is all well and good if the above set-up is accurately zeroed out on initial installation. Otherwise, any mechanical or other compensation must be accounted for before one is to trust the dial settings on the unit (see attached) .
Since my last posting, I had some time to play around a bit. First, as mentioned, I added some STP Octane booster. While my intent was to test the effect of this by itself, I figured I might as well also pull a plug and see what that might tell me (see attached). Correct me if I'm wrong, but the plug looked OK (this plug has 500 miles on it). I also figured I might take a look at the timing dial settings myself so as to have some sort of baseline to work from (whether or not they accurately reflected the actual values). Adding up the numbers ("init" and "3,000"), it looks like there is an "all-in" value of around 25 or 26 degrees. I will assume my builder measured a 3 degree correction advance to come up with the 29 degree all-in number he quoted me...
It is not easy to gain access to this settings panel (older unit) so I decided to dial back the "init" setting one degree, while adding 1 degree to the 3,000 range. Then, completely abandoning my systematic, one thing at a time diagnostic approach, I decided to turn the mixture screw a couple of notches to the right for some added enrichment.
Finally, after an examination (and subsequent tightening) of multiple vacuum hoses etc., I gave it a test drive. Yeah, I know....
Once it was properly warmed, I pushed it hard whenever I had a chance to lug it and the dieseling/pinging noise is now gone. I am of course happy about this, but not necessarily certain which of the above adjustments did the trick.
I suppose that I will delete the Octane boost with my next fill-up and see if the pinging returns. If so, I will isolate my adjustments to either the mixture or the advance in small increments and see what happens. Of course, if I have the opportunity to definitely check both the timing and the mixture, I will do so. While I believe the factory specifications for timing and mixture are valuable benchmarks for my adjustments, having a Euro P/C set as well as an Electronic ignition system (and digital WUR for that matter), may mean that I need to base my final settings more on real world data and trial and error more than stock settings.
Thanks again for all the input and Happy Holidays to all!
