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Problems with AC on my 67 Cougar.

AZCAT on Sat September 04, 2010 8:12 PM User is offline

Year: 1967
Make: Mercury
Model: Cougar
Engine Size: 289
Refrigerant Type: r134
Ambient Temp: 105
Country of Origin: United States

I am having a hell of a time with the air conditioning on my 1967 Cougar which was converted to R134a.

The system has a new Sanden 508 compressor, parallel flow condenser, upgraded evaporator, new expansion valve, new drier, and new lines.
I flushed the system with hecat, pulled a vacuum on the system down to 29.9 for over an hour, and it held 29.9 overnight. Today I attempted to charge it with Cool-Top. This is my first time using Cool-Top so I followed the instructions on the can. They recommend charging the system as a liquid only. As per the instructions, I opened the high side (engine off) and allowed the vacuum to draw in the liquid refrigerant. It did not draw in the entire can. I closed the high side, started the engine, and cracked the low side. It did not seem like it really wanted to draw in the refrigerant from the can. Can did not get cold either as I am accustom to.
I only got about 12oz in as I was a little alarmed by the pressures. I am told the converted system should take about 22oz. Center vent did not drop under 80 degrees. Suction line cold, discharge line hot, compressor hot, condenser hot.
My current readings (garage temperature about 105 degrees).

At idle 550rpm, 72/250
At 1,000 rpm, 42/277
At 1500 rpm, 32/295

Any suggestions? Could a restriction cause this problem? I used a couple copper flare sealing washers in the system. I had to reopen one of the lines prior to charging and I noticed the washer did not sit perfectly inside the flare and was partially blocking the flow…. makes me wonder.

Thanks,
Joe Gallagher

1stbscout on Sun September 05, 2010 12:57 AM User is offlineView users profile

It would seem there is something missing here. I just went to the CoolTop site to read up on it as this is the first time I have heard of it.
I am not sure why you would use this if you have done everything needed for a R134a retrofit. I realize they claim greater cooling etc. But you did not even check cooling with R134 first. 10* cooler from a properly functioning 134 system is below freezing. This will not help cooling.

So .... anyhow....... After reading your post I have some questions?
1. After you let the vehicle sit overnight did you connect the vacuum pump and run it before charging?
2. Why use the copper washers?
3. After you opened the system before charging did you once again evac the system to 29.9 ?
4. Did you hold the can upright when charging? Their site says there is a siphon tube so turning the can over will cause fractionation (separation of the multiple components). Then again maybe their site is a bit confusing only way to know for sure is to purge a small amount from the charge line an see if liquid is escaping.
5. What temps are the lines, outlet from the condenser, outlet from the evap?

It is slightly possible for a restriction to cause the high side readings. Normally your lows would be very low at the same time. Also if there is a restriction on the high side the component will be noticeably cooler after the restriction.

If I had to guess at it you have some air in the system or too much oil. Both will cause higher high side temps and pressures and will reduce cooling.

AZCAT on Sun September 05, 2010 1:56 AM User is offline

Thanks for the reply.

Quote
1. After you let the vehicle sit overnight did you connect the vacuum pump and run it before charging? 2. Why use the copper washers? 3. After you opened the system before charging did you once again evac the system to 29.9 ? 4. Did you hold the can upright when charging? Their site says there is a siphon tube so turning the can over will cause fractionation (separation of the multiple components). Then again maybe their site is a bit confusing only way to know for sure is to purge a small amount from the charge line an see if liquid is escaping. 5. What temps are the lines, outlet from the condenser, outlet from the evap?
1. Yes.
2. Precautionary measure on one the fittings (flare did not look so hot).
3. Yes.
4. I held can upside down as stated on can. I think the siphon tube you are referring to is found on the
large tanks only. I had 12oz individual cans. Can is actually labeled "this side up (bottom) for liquid".
5. I will have to check that tomorrow.

Just to clarify, a restriction would not cause an elevated low side reading? From what I have read (your post and others), the low side would be lower than normal, not high. 70 at idle freaked me out. I don't want to damage the compressor. What would cause such a high reading? It is obviously not over charged. As I mentioned before, I stopped at one can (12oz) due to the high pressure.

By the way, the car has dual 11" Spal puller fans which were ON at the time. I also drained the oil from the Sanden/filled with 6oz of correct oil.

Thanks again,
Joe

I hope to get everything sorted out so I can drive it soon:


Edited: Sun September 05, 2010 at 2:16 AM by AZCAT

bohica2xo on Sun September 05, 2010 12:33 PM User is offline

An undersized compressor, electric fans, AND magic in a can - the Trifecta. With a partial charge on top of that.

That cooltop can should say 10 degrees warmer on it. They claim a boiling point of -30f. It is only 40% 134a.

The pressures are hardly surprising, and reflect the partial charge. That refrigerant blend has a bubble point of 97 psi @ 70f, which tracks with your results. The TXV is wide open, and the partial charge is a foamy mess headed for the evaporator. You can't expect the 50% charge to carry away much heat, and you saw 80f vents on a 105f day.

The undersized compressor shows up as the huge swing between idle & 1500 rpm.

Get the full charge into it. That is the only way you can diagnose it.

The copper seal may have slipped, but those are designed to center - could it have slipped on disassembly? Use a dab of wax to bond it on when assembling the fitting - that sticky red stuff form a babybell cheese seems to be the favorite in the heavy equipment world. Use it on the outside edge of the copper, to keep it out of the system.

If you have a sightglass, use it. What kind of oil do you have in the system?

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

AZCAT on Sun September 05, 2010 9:00 PM User is offline

Thanks for the help.

I did not get a chance to work on the car today. Oil is Ester 100.

Edited: Sun September 05, 2010 at 9:02 PM by AZCAT

1stbscout on Mon September 06, 2010 12:48 AM User is offlineView users profile

Quote
Just to clarify, a restriction would not cause an elevated low side reading? From what I have read (your post and others), the low side would be lower than normal, not high. 70 at idle freaked me out. I don't want to damage the compressor. What would cause such a high reading?

1. Usually a restriction in the high side will not cause an elevated low. There are several things that will create a high low and higher than normal high side as well.
A. Just enough of a restriction to allow the liquid to partially flash to vapor but not enough to act as a expansion device. This would be something closer to a bend that
has too sharp a radius or a line with a slight kink in it. Anything more will cause cooling at the restriction.
B. A restriction in the system AFTER the point you have your low side gauge line connected to could cause the same.
C. Not enough charge. If the vapor returning to the compressor is at an elevated temp the compressor will add more heat while compressing it and you start with higher
temps before the expansion valve. This in turn drives the low side up and reduces the amount of cooling you get.
D. Too much oil in the system will cause higher than normal high and low sides.
2. Air in the system will cause a higher system pressure along with the above things under C and D.

If the vehicle was mine I would stick with either R12 or R134a. Both should give you the cooling you hope to attain if the system is built and charged properly. More than anything right now the temps I asked for are more important than anything else except the charge level. Without a reasonably "cool" high side liquid line that is completely liquid as it enters the expansion valve there will be little or no cooling and very little oil getting back to the compressor.

If what you say in your OP is factual and the system has been upgraded with the parts needed to increase condenser size etc. to optimized the system for R134a there should be no problem getting the system to cool well. I do have several other questions...... 1. How big is your crankshaft pulley? 2. How big is the pulley on the compressor? (the information I have says it is about 5 1/8 inch). 3. What is your idle speed?

If my memory serves me correctly and you have not changed too much, your crank pulley should be ~7 inches. With a 5.19 inch compressor pulley and a 600 RPM idle the Sanden displaces ~6500 cubic inches per min. As R134a has a specific volume roughly the same, at the working pressures your system should see, your compressor may be slightly small for the system you have installed. Personally I don't think it will be an issue BUT..........

bohica2xo on Mon September 06, 2010 2:15 AM User is offline

The OEM compressor was a York 210. 10.3 CID / rev. The Sanden is smaller. It must spin faster to make up the difference. The OEM system was designed around the volume of that York compressor.

While the SD709 would be a closer match than the 508, aftermarket companies seem to supply the 508 for this sort of thing. You give up some idle performance for the smaller, "better looking" compressor. Not as much as GM owners that swap the A6 for a 508 because the A6 was "ugly".

134a will cool the Mustang / Cougar of that vintage with enough condensor & airflow. I worked on a beast of a '67 stang with a 427 CID FE in it - headers & all. It was tight, but it cooled well on 134a. Without the PF condensor it would have been awful.

Be sure you clamped the TVX bulb to the evaporator suction, and insulated it very well. I had some trouble with the header heat on the stang feeding back into the TXV & causing evaporator flooding. Presstite tape, and plenty of it.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

AZCAT on Mon September 06, 2010 2:23 AM User is offline

Thanks guys. Great info. I will try to get those specs tomorrow (Monday).

1stbscout, I took a quick measurement and the pulley size is indeed just over 5", and the crankshaft pulley is about 7".

I will also try to add the remainder of the charge (regular r134a this time).

I really would like to learn more about auto air conditioning. I am the kind of guy that wants to do everything on the car myself if possible....down to investing in the tools to align my car at home.

Anyway, I am still getting used to this forum. I have a habit of pressing "reply" to the last post, and it posting a blank message... which I have to later edit to add my text.

Thanks again,
Joe

Edited: Mon September 06, 2010 at 2:44 AM by AZCAT

AZCAT on Mon September 06, 2010 2:06 PM User is offline

Alright gentleman, I added more refrigerant to the system. Current reading 40/240, 96deg garage temp, 80 at vents.

I used a voltmeter with a temp probe:
Discharge at Compressor: 123
Suction at Compressor: 44
Suction line connection at Evap: 45
Top of condenser to discharge fitting: 104
Bottom of condenser to drier fitting: 100
fitting before expansion valve: 113
Evap inlet after expansion: 53

iceman2555 on Mon September 06, 2010 3:52 PM User is offlineView users profile

Is this correct...a partial charge of COOLTOP and then another partial charge of virgin 134a ? If this is correct, now the system is seriously contaminated. Best advice is to locate someone who has the equipment to recover a contaminated system (good luck with this search) and have the system totally recovered. Probably what will simply occur is that the 'refrigerant' will simply be blown off.....that is not a legal act..but....in the real world...this is more than likely the method.
The system should be evacuated and recharged once more with virgin 134a...leave all the 'snake oil' stuff at the AZ/O'Reillys/Advance stores of the world. Get the 'GoodStuf'.
Recharge the system, dumping some liquid in is not a suggestion for a 'newbie'...but if this is the way you wish to go...go for it. Best method is to have someone charge the system for you utilizing the correct equipment. However, determine the charge rate of app 90% 134a to 12. Retest and supply info.
As bohica2xo states, the compressor is a bit small for this vehicle, would have suggested the use of a SD7H15, a larger displacement compressor and is great with 134a. The parallel flow condenser should allow for a full charge of 12 spec's. Stated earlier a lesser amount, then re read the post and noticed the use of the updated condenser.
Wonder if the fans are moving as much air as advertised?
Nice car....hope you are able to get it running soon.

-------------------------
The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

ice-n-tropics on Mon September 06, 2010 5:03 PM User is offline

Hi Joe,
My 2 cents
44/45 F suction temp at 600 erpm idle is normal with a SD508/SD5H14 (8.42 cu in. displacement/6815 cu in /min).
80 F louver temp is abnormal. Temp readings are dubious because refrigerant will not increase 13 deg. downstream of the condenser
Air off the evaporator could be in the range of 46 to 50F if the mode switch is in the max (recirculated) air mode, therefore, if the air at louver is really 80F, it may have been reheated due to a faulty blend air door or leaking hot water valve. Possibly the A/C mode is stuck in the NORMAL (outside air) mode as part of the abnormal 80F louver temp.
hotrodac

-------------------------
Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

bohica2xo on Mon September 06, 2010 6:06 PM User is offline

Ummm Yeah.

Looks like "more refrigerant" has put you closer to critical charge - the pressure drop on the low side indicates this.

I will just consult the Cooltop P/T chart, and see where you are at... hmmm no P/T chart on their website.

The charging instructions clearly state to dump two cans into the system - no mention of system capacity, or high side pressure. The instructions also tell the user to "top off with 134a" and to add 134a to the system "until the evaporator discharge line gets cold".

Wow, refrigerant so good we can throw away the high side hose! Top up your blend with 134a! Truly Magic in a CAN!

Here's the link if you think I made this up.


So the OP charges half the recommended initial charge of magic. It does not work. Now he has added "more refrigerant". It still does not work, but it is behaving differently. It is unclear if the additional refrigerant was magic, or simply 134a.

There is either a mensuration issue, or the refrigerant is re-heating 13 degrees from the dryer to the TXV.

To properly use a thermocouple on a metal line, you need to clamp it to the surface, and insulate the probe & line from the engine compartment airflow. A shop rag wrapped around the probe & tube usually does a fine job.

To measure vent temps, place the probe 3+ inches into the vent.


The current system status is "Peppermint & Puce". It may be upgraded to "Plaid" - pending more information, a 1500 rpm test & thermocouple data.


Now it is time to go make the R290 cook a meal, while ingesting some more hydrocarbons...


B.





-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

AZCAT on Mon September 06, 2010 6:23 PM User is offline

Thanks guys.

More than likely a measurement issue. I did not clamp/insulate the probe to the surface. That coupled with headers which give off a lot of heat...

From the passenger compartment I was able to place my finger through the inlet and touch the evaporator. I then fed the probe inside the box, touching the evap and it read 54 degrees.

I took the car around the block. My pen thermometer in the center vent read 70 degrees. I then fed the probe down the center vent about 5 inches; read 55 degrees.

I will keep at it and report back... I really appreciate the advice. THANKS.

AZCAT on Mon September 06, 2010 7:39 PM User is offline

Also, can anyone describe what kind of effect heat from headers would cause to the TXV? What is the proper method of attaching the bulb to the suction line? I'm looking for do’s and don’ts.

I will also have to verify the accuracy of the thermocouple and pen thermometer... there seems to be a large discrepancy between the two.

I also have a infrared thermometer for what its worth.

Thanks.

_______

Edit: Got it down to 60 degrees (pen thermometer, which I verified is accurate). I tightly clamped the bulb to the line and insulated it really well.

Does the rest of the TXV need to be insulated to the same degree or is it primarily the bulb?

I think bohica2xo hit the nail on the head. My car has headers and they were likely interfering with the TXV.

Edited: Mon September 06, 2010 at 11:40 PM by AZCAT

1stbscout on Tue September 07, 2010 12:33 AM User is offlineView users profile

If heat from the headers is effecting the TXV it will cause the high side to be lower than "normal" and the low side to be higher. As such if the evap is receiving too much refrigerant it cannot evaporate thereby reducing cooling.
The bulb should be securely mounted on the upper 1/3 of the line. Mounting it below the 9/3 o'clock areas can cause the oil in the line to effect the temps that the bulb senses. It should also NOT be mounted on a vertical run if it can be avoided.

Silly question.... how did you calibrate the thermometer?

AZCAT on Tue September 07, 2010 12:56 AM User is offline

Thanks for the reply.

I did not calibrate the thermometer. I have several different types (pocket/pen, infrared, and thermocouple). There was a discrepancy between the thermometers. I simply confirmed the pocket/pen thermometer was most accurate for reading center vent temps.

bohica2xo on Tue September 07, 2010 12:55 PM User is offline

Calibrate your thermometers in a bath of ice & water. immerse at least 3 inches of the probe in the bath, and calibrate after one minute. Your thermometer should read 32f.

If you have a small pocket dial type thermometer, it can be adjusted. With the probe still in the bath, hold the hex nut on the back of the dial. Grip the outside of the dial assembly with your fingers, and rotate the case until the pointer rests on 32f.

For digital equipment, just note the temperature offset, and calculate the correct temperature.

You can also check the instruments in boiling water. 212f is the temp, depending on altitude.


If your headers are close to the TXV, the radiated heat can warm the valve body and affect its performance. The sensing bulb should contact the line metal to metal. It should be clean. Once it is clamped to the line, you should insulate it with Presstite tape - the black tacky stuff that was on it OEM. You can (and should with headers) insulate the exposed suction line, the sensing line & the TXV. You might also consider some header wrap to keep the heat off of the firewall, evaporator case, etc..

On that big block car I used a radiant barrier on the liquid line, and and all the way to the evaporator case. Basically aluminum faced woven fiberglass cloth, you can buy it from McMaster-Carr as part # 88475K2 I used part # 1601T61 to secure the material around tubes. We went to the moon & back several times using that process, and it still works.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

AZCAT on Tue September 07, 2010 3:02 PM User is offline

Thanks very much! Clamping the bulb tight and insulating it (really well) helped a lot.

I am getting about 57 at idle now. Temp goes down more at higher rpms. 24 hours ago I was at 80 degrees!


I still need to insulate the rest of the TXV. The bulb is the only part well insulated at the moment. I ordered some more cork tape and will wrap the hell out of everything when it arrives.

Thanks again,
Joe

Edited: Tue September 07, 2010 at 3:05 PM by AZCAT

bohica2xo on Tue September 07, 2010 3:25 PM User is offline

Really hard to do any more system evaluation at idle.

With that compressor, you do not reach full compressor output below 2500 engine rpm. Any further testing you do should be done at 2000 engine rpm or above.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

AZCAT on Mon September 13, 2010 12:01 AM User is offline

Seems to be working great. Thanks!

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