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Re: a/c junk R-134 conversion- George Swift[240-260/1984] posted by abe crombie on
Saturday, 27 June 1998, at 9:43 a.m.
I exchanged the whole accessories bracket with p/s pump and a/c compressor from a 91 B230 240 onto a 1984 245 w/B21FTI and man is it ever an improvement. It quietens down the engine/driveline noise more than you would ever imagine. Apparently there is a good deal of noise that comes from the old style p/s pump with its less than fantastic bushings into the steering gear and is broadcast as noise through the steering column whether a/c is on or off but especially when its on. Everything bolted up and fit. The p/s high pressure hose had to be bent but screwed directly into new pump. I had to get a splice in low side charging port fitting as the compressor I used had no charge valves on it. (90 and before would have had these).
When you did the r134a cahngeover did you not also replace evaporator? The Volvo kit for up to 90 on 240's has an evaporator in it that is more efficient than the original. You still have the condenser efficiency issue to deal with and the resultant idle speed performance issues.
Re: a/c junk R-134 conversion- George Swift[240-260/1984] posted by Mikey on
Sunday, 28 June 1998, at 6:18 a.m.
When I did my conversion I did not change the evaporator. Some of the original
recommendations for R-134a have been reconsidered, such as hose replacement,
evaporator replacement. Optimal performance may be enhanced by evaporator
replacement but I decided to give it a try and feel my system performs as
well as it did with R-12.Two things I feel really helped: The use of ester
oil-it mixes well with any residual mineral oil. Volvo conversion kits include
PAG oil which does not mix well and would require more attention to flushing
the system=more labor. Poor mixing of dissimilar oils will degrade performance.
The second thing I did was to tweak the TXV by turning the screw inside about
1/2 a turn clockwise-narrowing the orifice. Then when I charged the system
I started with one pound of R-134a and added a little at a time until my
gauge pressures were where I wanted them. The system works very well here
in Atlanta with 90+ temp/humidity. Electric fan is a must-wired to compressor
the relay kicks the fan on any time a/c switch is on.
Now if I could convert my compressor/PS to B-230 style like Abe I would be in business!
p.s.- The smaller compressors use a Viton shaft seal which will leak with
R-134a. Used compressors from R-12 must have this seal replaced-the newer
stock compressors have a seal that is R-134a compatible but check it out
the parts dude may not be aware.
Mikey 1984 242ti
Re: a/c junk R-134 conversion- George Swift[240-260/1984] posted by abe crombie on
Sunday, 28 June 1998, at 9:43 a.m.
All the Volvo kits use ester oil also. PAG is only used as factory fill for the reasons you mention. Volvo is subsidizing (at least for now) the price of those kits. You can't buy an accumulator for a 700/900 series for what the conversion kit costs. The evaporator that is being included in the 90 and back 240 kit is more efficient than the original and when used gives a better performing system than it ever was when new. The kit has the high side hose, evap., exp. valve, all o rings, and receiver-drier. If you need to replace the high side hose (very common) or expansion valve (also very common) then the price of the kit makes it more cost effective. The weakness being that whichever way you go an auxiliary fan is needed to get any acceptable level of performance for persons that sit in traffic.