An engine builder did a test here with aproperly curved distributor against
the factory nissan (NLA) trans ignition on a U20 Solex (50mm) race engine
Over 6000 RPM it started to be noticeable but over 7500 there was a 5% gain
with the trans ign.
However when the same was done with similar bits on a Morgan V8 - a friend
told me - there was no difference.
Figure that out. (but I think it was only going to 6500 rpm)
Regards
Howard
-----Original Message-----
From: David R. Conrad [SMTP:conrad1@gte.net]
Sent: Saturday, 13 May 2000 4:27
To: Fred_Katz@ci.sf.ca.us
Cc: Daniel Neuman; Tomet9@aol.com; Datsun List
Subject: Performance with Pertronics (was re: dwell adjustment)
Fred:
I make no claim as to improved performance with the Pertronics, as I said
in my
post on dwell adjustment--I simply don't know if my recently improved
performance can be attributed, even in part, to it.
I can however, participate in a pseudo-scientific test in an attempt to
quantify
any difference.
The reader must (rather carefully) follow the rather complex situation I'm
about
to explain in order to avoid confusion ;-).
I have two distributors, essentially identical as to advance curve, etc.,
and I
will refer to them as "A" and "B". "B" for "bad", maybe ;-).
"B" was my installed dist. for many years until I started to notice that if
I
set the point gap on one lobe of the cam, it would vary by a thousandth or
so
from the gap set on another lobe of the cam. The dwell meter would also
"oscillate" slightly about a mean value.
I decided to substitute dist. "A" which did not exhibit these
characteristics;
in fact, with dist. "A" the dwell meter gave a "rock solid" reading.
I had been running with dist. "A" for quite a while (at least several
years)
when I decided to install a Pertronics unit with the hope of improving
performance. I installed the Pertronics in dist. "A". Turns out, I
installed
it incorrectly (I plead inadequate installation instructions) and I
experienced
several occasions of the car starting to miss, backfire and quit in some
bad
situations. Through consultation with "the list" (Jim Tyler, Dan Neuman) I
identified the problem as being the fact that I hadn't secured the ground
wire
to the advance plate, as it should have been.
So, having had my confidence in the Pertronics unit somewhat shaken by my
experiences while it was incorrectly installed, I decided to install it in
dist.
"B", and completely refurbish dist. "A" with all new components (points,
rotor,
condenser. and cap), properly gapped, so that I could just "slap it in" in
the
event of a Pertronics problem (if I was disabled on the "no shoulder, two
lane
road" on which I've had my most distressing problems).
Now Jim Tyler did not like the fact that I had installed the Pertronics in
"B",
the "lesser" of my two distributors, contending that "shaft slop" would
degrade
the Pertronics performance. No such "slop" was apparent to me--absolutely
no
discernible movement laterally. I attributed the slight gap variation to
cam
wear. (I agree it is difficult to rationalize how a rotating cam would
experience differing amounts of wear of the lobes).
Anyhow, the dwell meter shows a "rock solid" indication, whatever that
implies
with a Pertronics, and it runs (subjectively) "great". Dist. "A" with the
all
new points components did not work when I replaced "B" with it.
With "B" working well, I've developed enough confidence that, back up "A"
remains in my workbench cabinet, awaiting the time that the Datsun allows
me the
time to investigate the "why" of it not working.
Sorry this has gone on so long, much more so than intended. Anyhow, the
pseudo-scientific comparison motivates me to "slap in" "A" and get it
working
:-).
I welcome any thoughts regarding the conduct of my comparison tests. What
kinds
of things would best be compared? Hopefully, there can be a measurable
difference in performance and/or fuel consumption, but it would be just as
meaningful to find out there is no statistically significant difference.
Maybe
it will be possible to arrive at something better than the subjective
terms/opinions we use (nothing wrong with "sluggish", Fred ;-) )
--but I doubt it...
Dave
'"cool" '68 1600
Kailua-Kona
Daniel Neuman wrote:
> Hi Fred,
> Maybe you coudl explain to us (me mostly) how changing the
> dwell will make the car more or less sluggish??
> I did not notice any change (I think) When you say sluggish what
> do you mean exactly??
> Daniel
>
> > Dave,
> >
> > Maybe I'm alone in going with points over Pertronics. Perhaps if I used
a
> > hotter coil and knew how to tweak a Pertronics, the performance might
come
> > close to what I get with points.
> >
> > After rebuilding my U20, the engine was running great. Smooth idle,
quick
> > acceleration, due to most things on the engine being fresh. With about
100
> > miles on it, I put in a Pertronics and the engine response was sluggish
> > compared to before. I tried changing the timing, regapping the plugs,
and
> > tweaking the carbs but it didn't help. I happily re-installed the
points.
> > Thousands of miles later they are still fine.
> >
> > This wasn't my first exposure to Pertronics. My '66 1600 had one and
it's
> > performance was sluggish also, compared to my '70 1600 with points. And
the
> > '66 1600 had been recently rebuilt.
> >
> > I like the points as it gives me more control over tuning. Does anyone
> > know of a how-to site for using the Pertronics, with performance
> > comparisons to points?
> >
> > Fred
> >
> > ______________________ Reply Separator ____________________
> > > Subject: Re: dwell adjustment
> > > Author: "David R. Conrad" <conrad1@gte.net>
> > > Date: 5/12/2000 9:42 AM
> > >
> > > Tom:
> > >
> > > There has been a lot of recent discussion on the list after I simply
> > > mentioned that I had Pertronics in the question of dwell adjustment.
> > >
> > > I think that the "list" discussion speaks for itself; that is, think
> > > most users are pretty favorable towards it. Just getting rid of the
> > > points and the need for replacement/adjustment alone, in my
> > > estimation is reason for going for it (Pertronics).
> > >
> > > Hard for me to say, from a performance aspect, that it's made a big
> > > difference, because I was doing a lot of things about the same time
> > > (carb & valve adj., new plugs, etc.) resulted overall in the car,
> > > "running a LOT BETTER than it had in a long time", and still does.
> > >
> > > Hope this helps.
> > >
> > > Dave
> > >
> > > '68 1600
> > > Kailua-Kona
> > >
> > > Tomet9@aol.com wrote:
> > >
> > >> Conrad,
> > >>
> > >> Am a new member of the list and just wanted to know if
> > > installing a > petronics over stock points is that much more
> > > noticable when driving. I used > to have a allison pointless on my Z
> > > years ago, how different is this one?
> > >> Would appreciate a response if you have time.
> > >> Thanks,
> > >> Tom, 69/2.0
> > >>
> >
> >
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