Carl,
If by "internal spring loaded adjustment" you mean the center disk you
turn it clockwise to balance flow at part throttle and counter-clockwise to
measure/adjust at more open throttle settings; i.e. you close the annular gap
to balance flow at idle and open up the gap to balance flow at higher engine
speed.
The Uni-Syn is pretty simple--there's a vacuum port in the body of the unit
and by moving the adjusting disk in or out you increase (in) or decrease (out)
the airflow at the port at a given throttle setting. The partial vacuum
produced by the airflow over the port raises a small plastic indicator
("bubble") in
a vertical tube to give relative airflow rate as indicated indirectly by the
amount of
vacuum at the port (it's the same principal used by the Healey "ported"
vacuum advance mechanism, with a small opening behind the throttle).
In general, most gauges are most accurate in the center of the indicator range.
At idle, screw the center disk in or out until the plastic "bubble" is in the
center
of the vertical tube, then check the other carburettors and adjust until all
raise
the bubble the same height. Then, do the same with the carbs off-idle--you'll
need to move the center disc out quite a bit or you'll peg the bubble at the top
of the tube--to insure the throttles are all opening the same amount and adjust
your linkage accordingly.
The knock on the Uni-Syn is that you're changing the airflow with it; i.e.
you're
essentially choking the flow--and thereby altering the mixture--which is true.
However, since you're using it to assure all carbs have the same airflow, as
long as they are "choked" the same you can balance them.
Be sure to keep the indicator tube more or less vertical, and the same for each
carb as gravity has some effect on the "bubble." Also, be sure to keep a good
seal between the Uni-Syn "mouth" and the bore opening on the carb.
bs
********************************************
Bob Spidell San Jose, CA bspidell@comcast.net
'67 Austin-Healey 3000 '56 Austin-Healey 100M
********************************************
----- Original Message -----
From: "Dr. Carl Rubino" <ruvino@ripnet.com>
To: "healeylist" <healeys@Autox.Team.Net>
Sent: Saturday, January 08, 2005 8:17 AM
Subject: Uni-Syn
>I was going through some boxes of old parts and found my old uni-syn. Havn't
> used it in many years and have forgotten how. What I really don't remember is
> how to use the internal spring loaded adjustment. Any help to revive my
> increasingly impaired memory would be gratefully received.
>
> Carl
> BN-4(L)
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