<VV> Setting the timing on a '65 110
tony.underwood at cox.net
Mon May 25 17:52:43 EDT 2009
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.
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