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Re: [oletrucks] Fw: a/c

To: "Ronald I. Givens" <givens@hal-pc.org>
Subject: Re: [oletrucks] Fw: a/c
From: Thomas Allen <thallen@nwlink.com>
Date: Mon, 07 Jan 2002 23:04:01 -0800
I installed one in my 51 AD cab. I got the four vent model which is 
overkill. I chose the Old Air unit over the Vintage Air with under-dash 
vent manifold because the manifold interferes with my e-brake lever that is 
attached to the transmission and sticks up out of the floor next to the 
shift lever.

The instructions were complete and easy to follow although it probably 
helped that I understand how the systems work, in general. I had to 
fabricate mounts but expected that. Everything works as advertised and it 
keeps the cab cool (80) even in 105 deg. weather with the sun beating 
through the windshield.

Some picks and pans: The low speed on the blower is too high. Air for the 
defrost is cold much of the time but since it is dried air it seems to work 
OK anyhow. The water valve is either all on or all off so the unit takes in 
hot water, heats the air then cools it to the desired temperature, 
condensing out the moisture in the process. This is fine from a comfort 
standpoint but not from a fuel economy standpoint. It means that the 
compressor works too much of the time when the heater is on and that uses 
extra fuel. How much extra, I don't know but in 100+ deg. hot weather the 
AC cuts my mileage by about 10%. My solution was to put a cable operated 
water valve in series with the vacuum operated valve supplied with the 
unit. I cut the water flow back till the thermostat clicks on and off only 
at infrequent intervals like when pulling a hill. Of course, when it's 
really sloppy wet and the windows tend to fog up, I increase the water flow 
so more moisture is condensed out by the AC evaporator.

Something to consider when adding A/C to any 216/235/261 powered vehicle: 
The crank pulley allows only for one belt. On the 235 it's a narrow belt 
and it has to drive the water pump, fan, compressor and alternator. The 
narrow belts have a pretty short life when stressed that far. They stretch 
and wear into the shape of the pulley and if you let them get loose they 
glaze and begin to slip. Once that happens, its almost impossible to get 
them tight enough not to slip. And if you could, it would make short work 
of the water pump bearing. So, follow the directions on the belt package 
and readjust it after a few minutes running time and then again at regular 
intervals. Carry a spare and some belt dressing. Admittedly, part of my 
problem is the high-pitch, 6-blade, 18" truck fan that I need to keep cool 
when pulling hills in third gear. But that's not all of the problem.

What we really need is a double-groove harmonic balancer that sticks out no 
farther than the original (for fan clearence), and  accommodates two drive 
belts, with compressor and alternator mounts to match.

Tom Allen
51 3800

At 10:21 PM 1/7/02 -0600, Ronald I. Givens wrote:
>----- Original Message -----
>From: Ronald I. Givens
>To: old-chevy-truck
>Sent: Monday, January 07, 2002 10:21 PM
>Subject: a/c
>
>
>Howdy,
>can anyone tell me good or bad about Old Air Products (Hurricane a/c units)in
>Fort Worth, Texas...
>thanks for any info
>ron givens
>oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959

Tom Allen
Seattle, WA
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959

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