AC install after 460 swap

[Littlebeefy]

I'm finally getting around to installing my AC plumbing after the 460 swap in my 84 Bronco. I have retained all of the HVAC as it came from the factory (OEM style at least) with the exception of the compressor. I am switching over to a Sanden style compressor and moved it to the passenger side of the engine. All of the original wiring for the heater and AC is there as well.

I've never done A/C before, but I feel like I'm at least capable of duplicating the factory configuration for the plumbing and wiring. I am making my own lines. I guess #12 A/C fittings have gone out of style, so I am making an adapter to reduce the Accumulator output to #10 and then going directly into the Compressor suction side. The Compressor to Condenser line would be a #8 and so would the Condensor to Evaporator line. The orifice tube would drop inside the Evaporator inlet. I wouldn't use #6 lines anywhere.

So if I do this, and plumb and wire the system exactly as it came from the factory but with a Sanden compressor instead of the factory one, will it work?

[Pete Whitstone]

I certainly don't see why it wouldn't work, provided the compressor you choose is sized appropriately. But why go to the bother? Unless you work at a hydraulic shop, or have a friend who does, I'm not sure why you wouldn't just get factory-style stuff. That's what I did when I assembled my AC system.

Some of the early 80's hoses can be hard to find, but I upgraded to the serpentine belt system from the 90's, and all that stuff is readily available. So if I pop a hose or a compressor or whatever in the future, it's "I need x for a 95 F150" at the auto parts store and I'm all set.

Having said that, I have a lot of stuff on my truck that is custom, so I'm as bad as anyone about this.

Just curious what you view as the advantage to all the DIY/custom stuff.

[Gary Lewis]

Pete - I think the key is that his setup puts the compressor on the passenger's side of the engine.  So that requires custom hoses.

But I agree that it should work.

[Littlebeefy]

I always make my lines. Gary's right; I've diverted too far from factory to go to the bin for replacements. Plus it just gives it that "custom as all get-out" look. Check out this post:

https://forum.garysgaragemahal.com/Making-your-own-lines-tp123149.html

Thanks for the advice. I wasn't sure if switching the compressor style was a big deal. I don't really know anything about it (but I've never let that stop me before). I've been seeing the compressor manifold and cycle shut off questions and it made me think that there was a part of the conversion that I was missing.

[Pete Whitstone]

Well, that does bring up a question I don't know the answer to. On my system, which as I said is mostly based on stock stuff, there is no high pressure cutoff switch that I am aware of. There is a low pressure switch on the dryer, which prevents the compressor from coming on if there is insufficient charge in the system. So unless that switch is both high and low pressure, once the system is turned on, the compressor is on as well, it never "cycles" due to high pressure built up in the system.

So if that's the case, is the compressor from a "continuous duty" system different than the compressor from a "cycle duty" system?

[Gary Lewis]

Good question, Pete.  And I think the compressors stayed the same.

In this post on the AC Clutch Cycle and Pressure thread Nickelplate showed us that the manifold changed between '93 and '94 on the 460 trucks to incorporate the switch.  And indeed, Rock auto shows a 1993 F250 w/a 460 takes an FOTZ19D850F manifold while a '94 takes a F4TZ19D850F.

So that raises the question of if the compressors are different.  Here are the Rock Auto listings for the 1993 compressors for a 460 F250, followed by the 1994 compressors.  In the '93 listing there are 8 compressors, and in the '94 listing there are 7 compressors.  Of those, 6 of the 7 match, and that includes the Motorcraft compressor.  So I'd say the compressors are the same.

[Pete Whitstone]

Wow, excellent detective work, Gary. Good to know!

[Gary Lewis]

I had the same question lingering in my mind since I'm running the 1990 system w/o the switch. So when you asked I thought it was time to find out. Now we know.

[85lebaront2]

The low pressure switch is the cycling switch. The only "continuous duty" systems have at a minimum an expansion valve to control the amount of liquid refrigerant admitted to the evaporator. Some systems have both an expansion valve and some type of suction pressure or temperature valve to keep the evaporator at a minimum temperature of 34° F.

I have not had a Ford product since my 1971 Colony Park until my two Flexes with an expansion valve system. Chrysler still had them as recently as my 2005 Town & Country minivan.

[Littlebeefy]

The accumulator has the clutch cycle switch attached to it. According to the EVTM (and confirming Pete), the clutch cycle switch shuts down the compressor to keep the A/C from freezing over. Also, according to the EVTM, the clutch cycle switch energizes the A/C clutch field coil.

So what is "powering" the clutch cycle pressure switch? Is it always on when the ignition is on? Does sliding the control to "Max A/C" or "Norm A/C" power the pressure switch to energize the clutch coil. That's what the A/C troubleshooting procedures in the EVTM seem to imply.

Why did my original compressor hoses have a manifold attaching them to the compressor (is that even what that is)? Was that serving a purpose and do I need something like it for my new Sanden compressor? I saw the discussion that you're referencing, Gary, about the 460 MY changes. Frankly, I just don't understand what that means in terms of how I'm supposed to plumb and wire my replacement compressor (since that is all I am changing and my switch is attached to the accumulator).

[Gary Lewis]

Chad - Are you using a complete system from another year truck?  Or piecing it together?

I think at a minimum you need the equivalent of these two lines, from this page on Rock Auto.  The second one, which RA calls "manifold hoses", has the manifold that bolts to the FS10, and that's the part that changed from '93 to '94 with the addition of the switch.

And that switch is just in series with the low pressure switch on the accumulator, and that ties back to the control in the cab.  As you said, when you slide the control to Max A/C or A/C the line is energized and if both switches are closed the clutch on the compressor comes in.  IOW, the circuit goes from the clutch through the high pressure switch, if there is one, then through the low pressure switch, and on to the switch in the HVAC controls.

[Littlebeefy]

Gary - my truck was an 84 Bronco with a Windsor. It has the factory A/C. When I swapped to a 460, I kept all of my A/C setup original-style except for the hoses and the Compressor which is now this aftermarket Sanden unit:



Are you saying that I will need a hose manifold from a 93 460 to make a Sanden unit work with my 84 A/C equipment? If so why and how would I connect it to a different style compressor? When I look at the 93 460 in Rockauto, they show a Sanden style compressor that lloks like mine as being part of the dealer installed A/C package, which would not fit the hose you are suggesting:

The 460 Compressors

[Gary Lewis]

No, I thought you had an FS10 for some reason.  So you just need whatever connects to the Sanden.  And the connections in the picture are quite different than the manifold the FS10 takes.

[Littlebeefy]

Thanks, Gary. Answer one thing for my own edification. Is the only purpose that these A/C manifolds serve is to connect hoses to the specific style of connections used on the compressor, like the ones on the back of this 93 compressor?



The manifold serves no other purpose than that, correct? They are used as connections for pressure switches or filling ports or anything?

One more thing I was wondering about. The extra port on the side of my accumulator (back end of the attachment to the evaporator) is my low pressure service port? And I will need to have a high pressure port on the line that connects the condenser to the compressor? The only port that I can find on my original lines is on the line from the compressor to the condenser so I'm assuming that is the only additional port I need to replicate on my new lines.

[Gary Lewis]

Yes, the manifold just connects the lines to the compressor.

The port on the accumulator is the low-pressure switch.  But I don't think any of the lines had a high pressure port before 1994.

[Littlebeefy]

Gary, there are two service ports on the Accumulator. The one on the side is what the clutch cycle pressure switch attaches to, but there is another one on the back of the connection to the Evaporator (see the top view in the picture):



Can I charge the system from that extra port? That is on the low side, correct?

Also, the hose that I removed from my truck that connected the Condenser to the Compressor definitely has a service port. The replacements on Rock Auto also show a service port:



So I need to have a service port on my new line and this will be the high side for evacuation correct? If I don't have a port there, I don't know how else I'd be able to evacuate the high side.

[Pete Whitstone]

Gary Lewis wrote

Yes, the manifold just connects the lines to the compressor.

In my lines, I'm pretty sure the "manifold" also has the high pressure relief valve incorporated into it.

[Gary Lewis]

Yes, you should have a service port on the high side so you can watch that pressure.

As for the ports on the accumulator, maybe the pics below will help.  On the left is the 1985 system that came out of Big Blue, and on the right is the 1990 system that went into him.

So the fitting on the back side of the one that goes into the evaporator, the connection on the top in both pics, is the low-pressure service port.  And the other fitting is where the low pressure switch goes.

[Gary Lewis]

Yes, that's right.  The relief valve is there as well.  I forgot that, and it is the thing sticking out to the left.  

[Gary Lewis]

I added over 100 pages of HVAC documentation, as explained in the thread called, oddly enough, Documents Added To HVAC Section.  Maybe some of it will help.