<VV> 66 A/C question

[Cliff Tibbitts]

Frank's advice which appears below again is excellent.  If in fact you were
charging it with the lid up, that would explain the high pressures.  Below
are some numbers to shoot for taken from the 66 manual.

ambient temp- 80:  head pressure: 140-150, suction pressure: 14, discharge
temp, RH outlet: 35-40

ambient temp-90: head pressure 145-155, suction pressure 15, discharge
temp, RH outlet: 37-42

Total charge is as Frank noted: 4 lbs, 8 oz.


The above figures are for a properly sealed system (condenser seals and
engine compartment seals) using R-12, at the point at which the compressor
clutch disengages.  Make sure the cooling lever is all the way down.




> Notes:
>
> 1. Engine compartment must be sealed up on 66, 67 models. Tape rust
> holes! That worked for me...
>
> 2. Remove backup lamp assembly and run hoses through the hole, tape
> openings closed.
>
> 3. Sight glass should run clear when the charge is enough (or too
> much!), while compressor is running.
>
> 4. White bubbles usually means not enough R-12 yet. How many pounds have
> you put in? Note, some cans are only 12 ounces. System holds about 4.5
> pounds.
>
> 5. Tighten the belt. 200 psi is nothing in high temperatures. If it is
> squealing at 200 psi, something is wrong, start with loose belt. There
> is a reason there are so many braces on the old A-6 compressor. Clutch
> should easily handle 350 psi, but hope you never see that. If it slips
> at 200 psi, it is bad.
>
> 6. I do not have a set of gauges in front of me, but the low pressure
> side should run about 35 degrees F. , whatever pressure equals that on
> the gauge face. Anything lower than 35 and the evaporator can freeze up.
> Or so.... AT least the center dash outlet should not be below 35 degrees
> F. Shoot for high 30s to 40.
>
> 7. Temperature is actually controlled by thermostat cycling the
> compressor, but the charge has to be near correct for that to operate
> properly.
>
> 8. The rubber seals on top and bottom of condenser are very important.
> So is taking the condenser off the firewall and cleaning all the
> leaves/junk out from behind it. Also blow through the condenser to clean
> the fins. And comb the fins where they usually get flattened.
>
> 9. If you run the compressor with the engine lid open, pressure will get
> too high and rupture a hose or worse. Note, this can cause blindness if
> refrigerant gets in your eyes.
>
> 10. Old seat of pants rule, if sight glass runs clear with compressor
> on, then bubbles form about 2-5 seconds after compressor cycles off,
> charge is fine.
>
> 11. If center outlet temperature is high, low pressure is high, and
> sight glass does not get bubbles after compressor shuts off, system is
> overcharged. Hopefully you never get that far.
>
>
> Others may have different rules or observations...
>
> Frank DuVal
>
>
>
>
Cliff Tibbitts
cliff at tibweb.com