Spica backfiring and things Spica

["agiyo" <agiyo@xxxxxxxx>]

From: "Dean W. Cains" <dwc@domain.elided>
Subject: Re: Backfiring (Spica)

Hi Terry:

Have you seen this?  It's about the best Spica Tune-up guide I've seen:

http://alfaclub.org/techstff/tunespca.htm

There is a part about testing the fuel cutoff solenoid, which is very
simple.  Minor misadjustment of the mixture, or a failing TA can cause
backfiring, too, as can driving style.  If the revs are dropping, and your
foot is even slightly on the throttle below ~3000 rpm's, the engine will
backfire, so pay attention to that.

Dean is right on here; if you back partially off the gas, even a good Spica
pump will allow backfiring.  The fuel cut-off works when your foot's
completely off the pedal (and if you're not accelerating, you should be on the
brakes, right?)

The Spica tune-up Dean cites was written by Bob Parry, the guy who got me into
computers and my current job, and with whom I'm going to have lunch tomorrow.
It is excellent; anyone who follows it will have a great start toward proper
settings in a Spica pump.  Which leads me to another ongoing Spica problem we
may have solved tonight.

An out-of-state Alfa shop blamed a customer's pump for incurable rich running
and plug fouling, has apparently had customers going from one used pump to
another looking for one that works, while leaving the option for expensive
carburetor conversions.  But in the Spica-Alfa currently under discussion,
they had installed a 160F thermostat!  The thermostatic actuator does not
fully extend until about 175F, so the Spica pump thought it was running with a
cold engine and was supplying a rich mixture, all the time.  It's hard to
imagine how many Alfas have been maligned by people who didn't quite "get"
some technical aspect, Spicas prime among them.

Do not fit <175F thermostats to Spica cars running the proper thermostatic
actuators, be sure your thermostatic actuator protrudes the proper amount at
operating temperature (they last 5 or 6 years) and be sure the vital gap
between the (factory sealed, we hope) reference screw and bell crank is .019"
or less at operating temperature.  Only then can you make proper pump
settings.

And don't switch over to no stinking carburetors.  Think of originality, and
consider what future environmental conditions may dictate if nothing else.

Peace,
Joe Cantrell
Portland, OR, where AROO's +/- 35 car evening tour last night ended with a 5
or 6 Alfa scream 40 miles home through the hills.  O, mercy.
'72 Spider Mountain Road Slut
'73 Berlina with the Mortimotor close to dropping in.
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