<VV> Setting the timing on a '65 110

[Tony Underwood]

At 04:17 PM 5/25/2009, Harry  Yarnell wrote:
>Bryan's sorta right. I'd set the timing around 18° for starters. Then
>advance or retard  when spark knock is first noticed. With today's gas ,
>some diddling with stock settings is required.




Both ideas are pretty much workable.


The old-school musclecar routines for initial 
timing was "run what the engine likes" and pay 
little attention to factory "mandated" 
settings.   With today's fuels being somewhat 
flighty and other conditions influencing how the 
engine actually runs, the actual initial timing 
kinda falls into the "best guess" category.   I 
usually start out at around 10 before, then I run 
it, cruise it, nail it, lug it, then twiddle the 
distributor by increasing the advance until it 
pings then back off until it doesn't ping anymore.

Even THAT is just a starting point.   It's 
relatively safe to run a setting like that but it 
may not actually give you the best over-all engine efficiency.

I had a chance to "dyno tune" the '60 Monza and 
make timing adjustments on the fly, and what 
seemed like the best setting (most advance 
without pinging under load) in fact did not 
produce the most power for the same throttle 
setting.   Backing the timing off a tad beyond 
the no-pinging point seemed to allow the engine to make the most power.

In the case of the '60 Monza, the less than 
spectacular open-chamber design in the 80hp heads 
with its lousy flame travel characteristics certainly influenced the results.



The curve in the distributor is sure gonna make a 
difference too.    This is how the manufacturers 
are able to extract as much power and fuel 
mileage out of their engines as they do by 
carefully moderating mixtures and ignition 
settings constantly for the best output by means 
of long and intense research in designing 
computer programming of the engine management systems.

As mentioned, your mileage may vary.



I recall a modified production dragrace record 
holder who in the pre-computer early '70s 
dynotuned his race engine by carefully noting 
which ignition advance settings in a locked-down 
no-mechanical-advance distributor allowed the 
most out of the engine at specific rpm ranges, in 
increments of 500 rpm each.   He carefully 
plotted the curve that would be needed to 
duplicate such a plot via a LOT of work with 
springs, weights, and time on a distributor 
machine.    The results were a record-setting 
performance that got his car featured in a lot of hotrod magazines.

Of course, this wasn't exactly a new trick... but 
he was among the few who really took the 
procedure seriously and made it work for him.

Sorry, I'm rambling...  ;)

So in short...  again,  run what the engine 
likes.  And yes, seat-of-the-pants tuning does work.



tony..