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Intro & Nubee Question Pages: 12

AcMoron on Thu July 30, 2015 10:20 PM User is offlineView users profile

Year: 1973
Make: Porsche
Model: 914
Engine Size: 3.0
Refrigerant Type: 134a
Country of Origin: United States

Two weeks ago I had little to no knowledge of Auto AC. Not much has changed since then except after some Googleing I now understand the basic routing and a beginner's understanding of the theory. This will be the first of many questions and hopefully I can get this AC installed and working with some help here. My car is a 1973 Porsche 914 which was a mid engine air cooled 2 litre 4 banger. I installed a Subaru 3 litre 6 cylinder. The engine came with a compressor which if good is a bonus but I'll get to that later. I want to run metal lines with bulkhead fittings but I'm not clear which material(s) I can use. I can't TIG weld either so I suppose Aluminum would be out. I can however solder, silver solder, gas or TIG weld. Which metal materials do I have to choose from. TIA, Kent

Dougflas on Fri July 31, 2015 9:52 AM User is offline

I would not use metal lines. They do not flex as rubber lines do. I think you'll be disappointed in the performance of r134 in that foreign vehicle. I would stick with the original r12.

AcMoron on Fri July 31, 2015 5:50 PM User is offlineView users profile

It never had AC. It's a very small 2 seater w/ extra insulation so it won't take much to cool it down. The metal lines will run on the exterior of the cab, albeit enclosed, appx 3 ft then connect to rubber hoses at the ends. I had hoped that by running copper, SS, Al I would have some permanent type lines concealed in the valance. I could use rubber but it's temporary, large and heavy. If this is a pipe dream and won't work please tell me. One other question. Not to be a smart alek but why would r134 not cool a very small car when it previously cooled an 8 psg, dual moon roof station wagon? TIA, Kent

mk378 on Fri July 31, 2015 6:10 PM User is offline

Auto systems are almost always limited by the performance of the condenser, so a lot is going to depend on the size of the condenser you can install and how much air you can get through it.

AcMoron on Fri July 31, 2015 6:23 PM User is offlineView users profile

Hah, I'm learning already. It's an 11" x 21" parallel hi flow??? Is it big enough?

bohica2xo on Sat August 01, 2015 12:57 AM User is offline

Hard lines in the body section area good plan. Stainless or aluminum both work well, copper always seems to have issues.

What are you using for an evaporator?

The Subaru is a water pumper. What are you using for a radiator? Where is it mounted? How are you providing airflow?

-------------------------
"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.

AcMoron on Sat August 01, 2015 10:44 AM User is offlineView users profile

I haven't pulled the trigger on an evaporator yet but the model that seems to fit my needs/cabin is the slim line under dash AC/Heat by Vintage Air. It's a small 2 person cabin with console which will be trimmed down 2" to accept the evap unit. But I'm Hell bent on having some vents that I can aim my way. My radiator is from a Dodge 300G (which cooled a 6 w/AC) and twin fans controlled by the Subaru ECU. The radiator is mounted up front and resides in a sealed plenum. It gets plenty of air via the cut out in the front bumper and when the fans kick on it will hold a shirt against the bumper.
Should I mount the condenser about an inch in front of the radiator? And is there a prime location for the dryer? Such as distance from condenser, relative height to condenser, in cool air vs. behind the radiator?? Here is a link to my build thread. Go to page 6 about 1/2 way down. This will help some of this makes sense. http://www.914world.com/bbs2/index.php?showtopic=201776&st=40
BTW, thanks for the answers to these questions of mine. It helps a lot. Kent

mk378 on Sat August 01, 2015 11:27 AM User is offline

The condenser must be first so it gets the cool (ambient) air. If there is a gap between the condenser and radiator you need to close around the edges so that air can't bypass through the sides when the fans come on.

Drier can be mounted anywhere convenient between the condenser and TXV but it must be upright and also pay attention to the "in" and "out" direction of plumbing. This is because they depend on gravity to separate liquid from gas-- there is a dip tube to pick up liquid refrigerant from the bottom and send it "out" to the TXV.

AcMoron on Tue August 11, 2015 4:03 PM User is offlineView users profile

I returned my 1st condenser once I discovered it was too small. Replaced it with a 12x25 that covers 95% of the radiator. I test drove it in town and HI way with no noticeable temp increase so air flow restriction seems to be OK at this time. How it performs once the hot gas influences the condenser will be the true question. More questions to come shortly.

bohica2xo on Tue August 11, 2015 6:14 PM User is offline

Your best bet would be to use the entire stack from that Intrepid donor car. New fan set, new radiator, new condenser. it was designed to work well together. Of course the stack from the Subaru donor car would have been a good match too.

I have done V8 swaps on the 914. I predict heating issues and short fan life if you do not increase the intake and discharge area for the heat exchanger stack.



-------------------------
"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.

AcMoron on Mon August 17, 2015 8:20 PM User is offlineView users profile

OK, I'm back with some more Dumee questions. Looking for input on BeadLock, Aeroquip-EZ clip, BurgaClip fittings.
BTW

bohica2xo on Wed August 19, 2015 1:59 PM User is offline

Beadlock.

Buy this crimper:

Manual hose crimper

And buy your fittings & hose from AMA as well. I have found "offfshore" fittings on a popular online auction site that are pure junk. Customer brought them in to use, and I sent them home with him.

Beadlock is the industry standard, and very reliable. While the crimping tool seems expensive, it pays for itself quickly. Custom hoses mean several fitting sessions with the car. Any 45 or 90 degree fittings need careful planning for orientation before crimping. Carting that sort of thing back & forth to the hose shop is a lot of work & time. If you belong to a car club you will use it 5 or more times a year too...

Hope you live in a mild climate.



-------------------------
"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.

AcMoron on Wed August 19, 2015 3:03 PM User is offlineView users profile

That's a good tip on those fittings. I hate working with junk products. Tell me more about the "mild climate" comment. Is the concern about the size of condenser or air flow??? I agree on the tool cost offsetting the many trips back n forth and was going that route until I read about BurgFlex. They are touting 74% less permeation but as I've stated before; What do I know?" That's why I come here. On another note, does it matter if the outlet on the condenser is top or bottom? Also, I understand the importance of mounting the accumulator square but is there a height position relative to the condenser that it should be mounted? And, do you recommend a trinary switch over the 2 function HI/LO switch. TIA, Kent

bohica2xo on Wed August 19, 2015 3:55 PM User is offline

The condenser can lean forward or back a significant amount without issue, but the liquid line must come from the bottom of the unit.

The receiver can be mounted with the bottom in line with the bottom of the condenser if you want. It can be mounted several feet above the top of the condenser. Not critical at all.

That two ear hose clamp contraption is no substitute for a decent beadlock. The aeroquip stuff works, but by the time you buy 6 fittings you can own the crimp tool...

If you plan to use the Subaru compressor & ECM I would install whatever sensors & switches Subaru used in the relative locations - for example if there is a high pressure sensor in the line between the receiver and the condenser, put the sensor back in that line. Distance between components is not critical. The ECM makes decisions about fan speed based on compressor / refrigerant pressure / ambient temperature / ECT / TPS / RPM, etc. An FSM for the Subaru will cover that.

As for the climate comment...
Experience tells me you want bigger discharge areas in to the low pressure area in the wheel wells. And your inlet area is way too small. It makes the fans work very hard, and significantly reduces airflow. There is a reason water pumper swaps all eventually end up looking like Renegade did them. If you need the electric fans to live at freeway speeds you will have trouble.

Part throttle cruising around Santa Barbara? probably fine. Track day at LVMS? meltdown.




-------------------------
"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.

AcMoron on Wed August 19, 2015 4:18 PM User is offlineView users profile

Got it! That makes perfect sense. Thanks for all the great advice. AFAIK, I may have to increase the opening once the AC comes into play. The only time the fans come on presently is when I am in town. If above 95F they come on and off frequently. Otherwise they just kick in occasionally. They never come on when on the hi way or cruising the back roads. The area where the radiator inlet is located in a high pressure area and is quite efficient when moving. The wheel well cutouts provide some negative pressure but most of it occurs at the louvered floor panel. My inlet/outlet ratio is appx 1:1.7 so in theory I "should" be OK but I could be wrong about that. Now to go flip that condenser over and start a material list to plumb the AC system. I'll be back with more infantile questions.

AcMoron on Tue September 08, 2015 5:47 PM User is offlineView users profile

I'm back with more dumb questions. I'm getting close to finishing so look for an increase in nubee questions. 1st, what oil do I use on the O-rings? / 2nd, I hope to use the existing Subaru compressor. It was working 2 years ago and I'm hoping it still does. Everything else is brand new. Do I need to add oil to the system? Do you recommend flushing the compressor because I don't know where to start, if so? / 3rd, How long do I pull a vacuum? FWIW. I live in a low humidity climate, SoCal/ 4th, can I safely use one of those vacuum devices that are driven by the air compressor (it says it will pull 28.3") or will I need to purchase a true vacuum pump? I use the term "true" loosely as it would be a Harbor Freight pump. / 5th, and it is trivial but why do my instructions for the under dash Vintage Air evap say NOT to test the AC side until you have tested the "HEAT" side first? I'm going to have many more when it comes time to fill w/ Freon and use my new AC gauges, of which I have absolutely no clue. The gages do make me look smarter, though! AS always, TIA, Kent

mk378 on Tue September 08, 2015 10:20 PM User is offline

Use mineral oil or Nyloq on o-rings. Flushing a compressor consists of working new oil through it by turning at low speed with the ports open on a bench. Never put solvent into a compressor. Assuming the other parts are new and dry, yes you would need to add oil, the amount for a custom system is a guess but you do have longer than usual lines. The air powered vacuum pump is not adequate.

AcMoron on Wed September 09, 2015 12:37 AM User is offlineView users profile

Perfect and thx for the quick reply. I feel a little stupid about the o-ring lub but I'm new to this and was afraid of contamination. I'll purchase one of those pumps this week. Thx again, Kent

Cussboy on Wed September 09, 2015 9:36 AM User is offline

Quote
Originally posted by: mk378
Use mineral oil or Nyloq on o-rings.


MK378 means refrigeration (R-12 type) mineral oil, not drugstore mineral oil !!!

AcMoron on Wed September 09, 2015 4:04 PM User is offlineView users profile

Thx for that clarification. I will be using R-134 so can I use the same oil as I put in the system to lub the rings? Also, about how much oil would you guys use to flush the comp. 8 oz.? I'm going to look at youtube to see if there is a video on a comp being flushed. Thx again, Kent

bohica2xo on Fri September 11, 2015 12:38 AM User is offline

Flushing compressors is covered here:

Compressor Flushing Procedure

-------------------------
"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.

AcMoron on Sun September 13, 2015 9:18 PM User is offlineView users profile

That reply was just in time. I had just pulled the compressor and saw this reply. I put 8 os of PAG100 in the suction side before it spit anything out after connecting it to my cordless drill. Does this indicate the capacity of my particular compressor is 8oz? I read online that the amount of oil needed is stated on the compressor but I'll be hanged if I can see it. The oil that did come out was clean so I'm wondering if the compressor had leaked the oil out previously and was dry before my adding oil today. And if I don't need to run another bottle through it do I leave that oil in it and bolt it back onto the engine? As always, thx for the help. Kent

bohica2xo on Fri September 18, 2015 8:08 PM User is offline

Sorry, been away for a bit.

If you put 8 ounces in before any came out, it was a little short on oil. Clean is good.

I would place the compressor in a pan with the ports at the lowest point, and let it sit overnight. Measure what drains back out.

Yes, some oil stays with the compressor.

-------------------------
"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.

AcMoron on Sat September 19, 2015 10:21 AM User is offlineView users profile

No worries, I'm grateful for the help. So let me see if I understand. If I drain & measure the oil that came out I will know the oil capacity of my compressor? Then just replace that same amount back into the compressor before I add Freon? TIA, Kent

bohica2xo on Sat September 19, 2015 3:01 PM User is offline

We covered most of this in a Kit Car thread recently. Your car, rear engine Kits and the Fiero all share similar layouts. Your OEM oil charge + an estimated quantity for the longer line...

Try this thread first, then ask about anything that does not make sense:

Kit Car oil charge thread

If you put 8 ounces in, got 1 ounce from the discharge port - that leaves 7. If you drain 3 more ounces that means 4 ounces are "normally" trapped in the compressor...

-------------------------
"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.

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