The biggest reason the colortune type tools don't do a perfect job on B
series engines (and A series for that matter), is the siamesed exhaust
port for #2 and #3 cylinders along with the less than optimal water flow
between the two center cylinders. This leads to nos 2 & 3 running a bit
warmer than 1 and 4, consequently they are leaner mixture wise.
If you use the color tune and keep this in mind, you will insert the
"plug" in #2/#3 cylinders to set the mixture. This will result in nos 1 &
4 running a bit richer than optimal, but rich is definitely better than
two cylinders running lean!
The Uni-Syn is NOT a tool to set the mixture. It does nothing more than
measure the airflow of the carbs, and will not indicate nor react to
variations in mixture (until they become so far outside normal limits you
can detect it with your ear!). If you try to use the Uni-Syn to set the
mixture, you will be fiddling with the carbs til the cows come home.
They, on the other hand, are great for equalizing the Idle on twin carb
cars. With both carbs flowing equally, idle will be smooth and
effortless.
Use the Uni-syn for what it was made for. And mixture adjustment is not
one of them.
Rick Morrison
72 MGBGT
74 Midget
On Fri, 24 Apr 1998 10:38:54 EDT AKBLACKLEY <AKBLACKLEY@aol.com> writes:
>I havent used this tool myself, but I remember John Twist stating that
>it
>doesnt give a proper reading for use on MGBs (re: MOWOG 1500 to 1800)
>engines
>and advised against using it. This was at a club meet in 1992. Anyone
>have
>direct experience? In my experience a Uni Syn and some patience yields
>pretty
>good results. When tuning SU carbs it is critically important that
>throttle
>shafts are not leaking. Cheers, Andy Blackley
>
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