A/C Parts Indentification

[bfloyd]

Getting to the point where I'm ready to install the new R134 system into my car, and I have a couple of questions if anybody can answer. The original R12 setup had the old-style accumulator with the hose fitting to the compressor on the bottom, so it only had the one "Low Pressure" Cut-Off switch - no High Pressure switch anywhere to be found.

New parts and pieces arrived last week and I have everything sorted out except for to pieces.

This fitting goes on the bottom condenser connection. The end with the red cap hooks to the condenser, the end with the blue cap mates with the small diameter hose that runs back to the evaporator and orifice tube. What does the nipple in the middle do? It seems too small for another pressure switch, unless the High Pressure switches had smaller diameter threads?
http://i.imgur.com/l1nO70Vl.jpg

On the accumulator...all of the fittigns can be identified except for one.
http://i.imgur.com/XKbYb6jl.jpg (http://imgur.com/XKbYb6j)

Yes, I've tried asking the vendor who I bought them from.... which is why I'm now asking here.

[Josh]

I assume the fitting on that tee is for the high pressure switch. does it have a valve core in it?

That second fitting is not used. That accumulator is actually off of a corvette.

[Bitsyncmaster]

I assume the fitting on that tee is for the high pressure switch. does it have a valve core in it?

That second fitting is not used. That accumulator is actually off of a corvette.

You would need the high pressure switch on the high side line (before the orifice).

[Henrik]

I assume the fitting on that tee is for the high pressure switch....

+1


That second fitting...

Perfect for hooking up your manifold gauges to in order to read/calibrate the cut-in/cut-out pressures of the switch.

[bfloyd]

That Tee fitting does have a schrader valve core in it.

Since my car never had a High Pressure switch before... How would it wire in and to what? Since there is no High Pressure switch included with this kit, I'm assuming I'll have to go out and find one somewhere locally.
What exactly should I be looking for?

[Morpheus]

As a fellow early VIN owner, I would recommend that you don't worry about the high pressure switch. Wiring it up will involve a lot of hassle.

[Josh]

The high pressure switch is a normally closed switch in series with the low pressure switch.

When you turn the mode switch to a/c the power is routed through the high pressure switch, then to the low pressure switch, then to the compressor clutch. So basically if the two switch conditions are satisfied, the clutch will engage.

[Bitsyncmaster]

Since my car never had a High Pressure switch before... How would it wire in and to what? Since there is no High Pressure switch included with this kit, I'm assuming I'll have to go out and find one somewhere locally.
What exactly should I be looking for?

It's normally wired in series with the low pressure switch. So you want a normally closed switch that opens when pressure goes to high.

[Josh]

As a fellow early VIN owner, I would recommend that you don't worry about the high pressure switch. Wiring it up will involve a lot of hassle.

I would worry about a high pressure switch.

If your fans go out or some other sort of failure to cause the system pressure to increase the only point of relief is now a hose blowing off or a component rupturing. I would say its worth the "hassle".

[Morpheus]

I would worry about a high pressure switch.

If your fans go out or some other sort of failure to cause the system pressure to increase the only point of relief is now a hose blowing off or a component rupturing. I would say its worth the "hassle".

If the switch wasn't there from the factory, as it wasn't on early VINs like his car and mine, then it's not something that his car absolutely needs. He would have to completely construct his own wiring harness for it, and unless there is a how-to documented procedure on this, then it's probably not worth the effort.

[Josh]

If the switch wasn't there from the factory, as it wasn't on early VINs like his car and mine, then it's not something that his car absolutely needs. He would have to completely construct his own wiring harness for it, and unless there is a how-to documented procedure on this, then it's probably not worth the effort.

You have too much faith in the dmc engineers. Not to mention Lucas wiring. This is concerning!

It wouldn't be that hard. Just cut the 12V lead to the low pressure switch and wire in the high pressure switch. 10 - 20 minutes of work.

Here is the high pressure switch. I tried to cross reference one, but most two wire switches are normally open
http://store.delorean.com/p-7722-hi-press-cut-out-sw.aspx

[bfloyd]

It's normally wired in series with the low pressure switch. So you want a normally closed switch that opens when pressure goes to high.

So, if I were to install a High Pressure switch, and it is to be wired in series with the existing Low Pressure switch... would it look something like this?
http://i.imgur.com/QB4mYHsh.jpg

[Josh]

So, if I were to install a High Pressure switch, and it is to be wired in series with the existing Low Pressure switch... would it look something like this?
http://i.imgur.com/QB4mYHsh.jpg

Exacty!

You can determine the hot wire by unplugging the low pressure switch connector, turning the mode switch to a/c, then finding the wire that is producing 12v. As a check, if you apply 12v to the other terminal, the clutch will engage.

[Morpheus]

I can see the importance now of adding this HP switch. I bumped an older thread on the subject without noticing the question got answered here. My bad.

I thought it was going to require running new wires to the fuse box area and such, but it looks like that's not the case at all.

[Farrar]

I did exactly what Barney proposed, adding the switch in series. My car had an "early VIN" system. Charging the system one very hot day, I didn't realize that I had a cooling fan out... I turned away from the gauges to talk to someone, and as we were chatting... *BANG* went the high-pressure hose! When I repaired the system, I added the high pressure switch for some peace of mind.

[Morpheus]

I did exactly what Barney proposed, adding the switch in series. My car had an "early VIN" system. Charging the system one very hot day, I didn't realize that I had a cooling fan out... I turned away from the gauges to talk to someone, and as we were chatting... *BANG* went the high-pressure hose! When I repaired the system, I added the high pressure switch for some peace of mind.

You wouldn't happen to know what parts you purchased to make that happen would you?

[Farrar]

You wouldn't happen to know what parts you purchased to make that happen would you?

This was several years ago, but assuming my memory works I bought the following from SpecialTAuto:

- set of 3 (2 "spliced") hoses for R-134a
- R-134a compressor
- high pressure hub (sight glass, HP relief valve, & HP cutoff switch)
- accumulator
- variable orifice valve

In the process of removing my old hoses, I caused a breach in the evaporator tube. I purchased from DMC Midwest an "evaporator kit" which included (I think) a low pressure switch and tar tape for sealing up the evaporator box. The kit may have included another accumulator, too -- I honestly don't remember.

FWIW, on my car, some frame rust had cause the epoxy to bubble up in some areas, so when installing I couldn't push or pull the hoses through without some difficulty. I removed the body bolts from underneath the console (two on each side if memory serves) and lifted the front of the car from the jack plates (instead of the frame as I normally do). That gave me the extra "wiggle room" to push the hoses through.

[FABombjoy]

Be sure that your old/new compressor has the pressure relief valve (PRV, HPRV) installed in the cylinder head (backplate). It looks something like the hex-shaped doodad on the left:

http://uploads.tapatalk-cdn.com/20131015/9ydu4yjy.jpg

[Henrik]

Be sure that your old/new compressor has the pressure relief valve (PRV, HPRV) installed in the cylinder head (backplate). It looks something like the hex-shaped doodad on the left:

http://uploads.tapatalk-cdn.com/20131015/9ydu4yjy.jpg

+1.
The picture shows the back of an SD-7 (with the PRV between the "S" and the "D"). The stock SD-510 does not have a PRV (IIRC) but as long as you have the high pressure cut-out switch wired in you're OK.

Also, maybe it's obvious, but the HP switch should be set for a cut-out pressure that is slightly less than the PRV. The latter is a last-resort type thing (designed to release at about 450-500 psig) and when those things blow you'll have a engine compartment nicely coated with sticky compressor oil. Makes a mess.

[FABombjoy]

The stock SD-510 does not have a PRV (IIRC) but as long as you have the high pressure cut-out switch wired in you're OK.
The Sanden QM head is an exact OEM replacement and provisioned for an HPRV. A bit challenging to find but there are some on eBay right now.


The latter is a last-resort type thing (designed to release at about 450-500 psig) and when those things blow you'll have a engine compartment nicely coated with sticky compressor oil. Makes a mess.
I thought about that, but then I thought about having an oil coated tire. I think I'm happier with a compressor mounted HPRV :D

QM head:
http://coldhose.com/media/catalog/product/cache/1/image/39a31c89d93b1f0e8473dc2722e8793f/q/m/qm2.jpg

[Bitsyncmaster]

You could wire the high pressure switch into either wire going to the low pressure switch.

The PRV valve on the HUB with later style AC systems. The hub also mounts the high pressure switch.

[Farrar]

when those things blow you'll have a engine compartment nicely coated with sticky compressor oil.


I thought about that, but then I thought about having an oil coated tire.

Hm, maybe putting mine by the condenser wasn't such a bad idea after all... Then again -- I may just end up with a different tire coated with oil. Damned if you do, damned if you don't! LOL

[bfloyd]

Going over my parts on hand at home during lunch, I realized that the original "Compressor Hose Bracket" (DMC Part Number:105845) probably won't work for this compressor that I have because of the cutout for the old hose fitting on the left side of the compressor. It almost looks as if any old piece of bar stock metal with a hole in it would retain the new hose fittings to the back plate of the compressor, but I'd rather find one ready made for the job at hand.

I've tried searching for "Sanden Compressor fitting retainer plate" on Google, but got nothing useful. Anybody know what this part might be called?

[FABombjoy]

It will work. I have mine set so that side with the cutout is on the suction port. Just be sure to hold it square until the fittings fully seat into the head.

[David T]

Not having a high pressure safety switch is a bad idea. The next thing to protect the system from an overpressure condition is the safety relief valve if you don't burst a hose first. There are several conditions that can cause a high pressure problem:
1) too much refrigerant
2) one or more fans not working or a blocked coil (not enough air passing over the condenser coil)
3) moisture in the system freezing and blocking the orifice tube
All of these can happen and the high pressure switch is cheap insurance. If you are doing your own work, adding a high pressure switch is not a big deal. The factory saw fit to add it during production realizing it's value, you should too.

[axh174]

You could wire the high pressure switch into either wire going to the low pressure switch.

The PRV valve on the HUB with later style AC systems. The hub also mounts the high pressure switch.

Dave, my memory is really fuzzy on this since I did my conversion/upgrade almost 9 years ago now, but 2234 used to have the "early VIN" setup where there was no sight glass or high pressure cutoff switch. I purchased the site glass and high pressure switch from Special T Auto when I did my R-134a conversion and I don't remember having to cut into my harness to connect it. I seem to recall that either the connector was already part of my main wiring harness (but wrapped up and hidden away) or there was a port for the connector's "sub-harness" already in my main harness (kind of like how the connections for the heated side mirrors already exist in the door harness).

Am I remembering incorrectly? Maybe 2234 fell into a looney middle ground where it had a more recent wiring harness but still had the early VIN accumulator setup?

[Henrik]

FWIW, here is what I purchased from SpecialTauto about 10 years ago when converting R134a:
http://www.specialtauto.com/delorean-parts/AC-Cooling.html

More specifically:
http://www.specialtauto.com/delorean-parts/images/ac-hub-assembly.jpg

Back then, at least according to my records, it was known as part number 30692 and cost $129.95. It was easy to wire in the HP switch like shown in one of the previous posts.

[Bitsyncmaster]

Dave, my memory is really fuzzy on this since I did my conversion/upgrade almost 9 years ago now, but 2234 used to have the "early VIN" setup where there was no sight glass or high pressure cutoff switch. I purchased the site glass and high pressure switch from Special T Auto when I did my R-134a conversion and I don't remember having to cut into my harness to connect it. I seem to recall that either the connector was already part of my main wiring harness (but wrapped up and hidden away) or there was a port for the connector's "sub-harness" already in my main harness (kind of like how the connections for the heated side mirrors already exist in the door harness).

Am I remembering incorrectly? Maybe 2234 fell into a looney middle ground where it had a more recent wiring harness but still had the early VIN accumulator setup?

My car had the original hub style setup. So both the high and low pressure switches already existed. I also got Special Ts hub so it was basically the same as the original hub.

[bfloyd]

Got a lot of work done today on my new AC system, however I got a little too aggressive with the wrench when mounting the hoses up to the compressor and stripped the threads out of the soft aluminum compressor head. I've found a replacement on-line for around $28, so it's not the end of the world or a costly mistake.

There HAS TO BE a better compressor head out there that has BOTH the suction and discharge threaded ports oriented at 90 degrees from vertical AND has a integrated pressure relief valve? I just can't find it.
http://i.imgur.com/POuHMtGl.jpg


http://i.imgur.com/yohXjUpl.jpg

Question? Do AC compressors HAVE to be mounted where the oil fill plug is on top? If compressor can be rotated 90 degrees, then I could use the compressor head that came with the compressor, however it wouldn't have the pressure relief valve.

Thoughts?

[Bitsyncmaster]

Got a lot of work done today on my new AC system, however I got a little too aggressive with the wrench when mounting the hoses up to the compressor and stripped the threads out of the soft aluminum compressor head. I've found a replacement on-line for around $28, so it's not the end of the world or a costly mistake.

There HAS TO BE a better compressor head out there that has BOTH the suction and discharge threaded ports oriented at 90 degrees from vertical AND has a integrated pressure relief valve? I just can't find it.
http://i.imgur.com/POuHMtGl.jpg


http://i.imgur.com/yohXjUpl.jpg

Question? Do AC compressors HAVE to be mounted where the oil fill plug is on top? If compressor can be rotated 90 degrees, then I could use the compressor head that came with the compressor, however it wouldn't have the pressure relief valve.

Thoughts?

The Sanden books say you don't have to have the fill plug on top.

Make sure your bolt is long enough to use all the threads. The Special T and DPI hoses use a larger fitting that require a longer bolt.

[bfloyd]

The Special T and DPI hoses use a larger fitting that require a longer bolt.

My intention is to totally eliminate that bolt if possible. If you can tell from the photos I've got the DPI kit.

I'm seriously considering pulling the compressor, removing the new Sanden QM compressor head that was included with the DPI kit, removing the pressure relief valve from it, and drilling and tapping the Sanden FN compressor head that came on the new compressor and putting it back on the compressor. The alignment pin holes on the compressor head will allow it to be mounted with the ports at either the 12 o'clock position or the 6 o'clock position. The way I have my fitting oriented, the 6 o'clock position will work perfect in my application.

[DMCMW Dave]

My intention is to totally eliminate that bolt if possible. If you can tell from the photos I've got the DPI kit.

I'm seriously considering pulling the compressor, removing the new Sanden QM compressor head that was included with the DPI kit, removing the pressure relief valve from it, and drilling and tapping the Sanden FN compressor head that came on the new compressor and putting it back on the compressor. The alignment pin holes on the compressor head will allow it to be mounted with the ports at either the 12 o'clock position or the 6 o'clock position. The way I have my fitting oriented, the 6 o'clock position will work perfect in my application.

I'm glad you mentioned that. We have one of those that came in here already put together. I think we need to "correct" the line orientation. The biggest issue is that if we were to install the R134 adapters, they would hit and dent the engine cover screens. I/'m worried that if I rotate the lines completely upside down I won't be able to get the gauge fittings on it. 45391

But I'm not a fan of running an R134 system with R12 fittings on it either.

[bfloyd]

If I put the FN compressor head back on with the suction and discharge connections at the 6 o'clock position, the service ports on the fitting would be upside down and hard to access. If I rotated the compressor in the engine mounting bracket (where the oil fill port was at the 9 o'clock position) the service ports would also be oriented at the 9 o'clock position. That sounds truly like the better option.

[bfloyd]

I haven't even tried to see if the 90 degree hose fittings would even clear the engine cover if they came off the top of the compressor. Might experiment on Sunday afternoon.

[DMC5180]

My intention is to totally eliminate that bolt if possible. If you can tell from the photos I've got the DPI kit.

I'm seriously considering pulling the compressor, removing the new Sanden QM compressor head that was included with the DPI kit, removing the pressure relief valve from it, and drilling and tapping the Sanden FN compressor head that came on the new compressor and putting it back on the compressor. The alignment pin holes on the compressor head will allow it to be mounted with the ports at either the 12 o'clock position or the 6 o'clock position. The way I have my fitting oriented, the 6 o'clock position will work perfect in my application.

This is my recent just before DCS installation using a SD7H15 compressor with a vertical port head w/ HPRV and oil fill port at 12:00

I was originally going to mount the compressor with S D Ports horizontal. Due to the Charge port locations on the hose elbows I opted for the vertical port configuration. Note the SD7 is Much quieter than the original compressor. I never know when it kicks in or out. I could always hear and feel the old SD5.

45392


45393


45396 High pressure switch harness Connector location in passenger side foot well


45397 New High pressure switch location at condenser outlet. I bought a new HP switch and NOS HP switch harness (Late style) its about 4-5 feet long. I did not want a bunch of butt splices to make the old one work.



45399 New replacement accumulator repositions the LP switch. I had to manipulate the Evap/Orifice tube line up about 1/2 -3/4" to clear it. I could have positioned it down too. It was a 50/50 decision.

[FABombjoy]

I got a little too aggressive with the wrench when mounting the hoses up to the compressor and stripped the threads out of the soft aluminum compressor head
Almost exactly the same thing happened to me, except instead of stripping, the head cracked apart between the ports.

[Bitsyncmaster]

Almost exactly the same thing happened to me, except instead of stripping, the head cracked apart between the ports.

When there is an O-ring seal, you need very little force when you tighten. Just use enough to prevent vibration from loosening the joint. Same goes for the joints that are threaded and have O-rings.

[Delorean Industries]

Sent you email Barry. I'm out a few more days but will have my shipping help get one out to you asap.

[bfloyd]

The Sanden books say you don't have to have the fill plug on top.


http://i.imgur.com/U6jODzNl.jpg

[Jonathan]

This is my recent just before DCS installation...

45392

45393


OT, sorry, but Dennis, where'd you get those little three-hose spacer bracket jobbies on the blue vacuum lines? That looks really nice. Much better than my zip-ties!

[DMC5180]

http://www.carparts.com/details/Taylor_Cable/Spark_Plug_Wire_Loom/T6442709.html?TID=gglpla&origin=pla&gclid=CLDkh4-LxM4CFUUdaQodPYQACg

Those are for 10mm wires.
I think these were direct fit for the hoses.

I did some other stuff that required a mix of hole sizes. For those I used the 8 mm set and up sized a hole as required with a drill.


Dennis

[bfloyd]

Got a little creative in the garage last night. Since I had the extra compressor head that came with the new compressor, I decided to see if I could make it work for my hose orientation. I really prefer the "fixed" cast aluminum suction and discharge connections on the spare head, as opposed to the "hold the hose fittings on with a chunk of metal and a rusty bolt" method.

I took the compressor back off the car, took it to my bench and started to dissect it to do a little "creative engineering". Removed the head, the head gasket, and carefully lifted the valve plate assembly off the compressor and set it to the side. The valve plate assembly had two rolled steel alignment pins that assures you put it back together correctly, but also keeps you from rotating the head any direction except 12 o'clock or 6 o'clock. I wanted my fittings to come off the compressor at the 9 o'clock position, but wanted to maintain the orientation of the oil fill plug on the top of the compressor. Took my Dremel tool and carefully cut the rolled steel alignment pins off of the valve plate assembly. Washed it down with mineral spirits to remove any stray metal shavings, then placed the valve plate assembly back on the compressor. The alignment of the valve plate assembly will be held in place with the 5 long cylinder head bolts when finished.

Took the compressor head with the stripped bolt hole and removed the High Pressure Relief Valve (HPRV). Took my tap and die set and determined the correct thread and pitch of the threads on the HPRV, and drilled and tapped the new cylinder head to accept the HPRV. Cleaned all the metal shavings off the inside and outside of the head and installed the HPRV in the new head. Put the newly reconfigured head back on the compressor and torqued the bolts down and remounted it on the car.

Worked like a champ. Hoses and service fittings are now accessible, and everything clears the closed engine cover with room to spare. Taking to my local mechanic later this week to evacuate and charge the system.

http://i.imgur.com/jcLQIPkl.jpg

Have no idea why the engine looks blue in this, but I promise it's not. Must we a weird phone camera anomaly.
http://i.imgur.com/aepx7iNl.jpg

http://i.imgur.com/lz1JO2Al.jpg

[Farrar]

Nice work! :thumbup:

[Morpheus]

Barry, that looks amazing! Great job!

[bfloyd]

The moment of truth comes on Thursday morning as I've got an appointment with my local mechanic scheduled to "go over my work" (i.e. "check my fittings and connections") and evacuate and charge the system. I've got a car show I'm attending on Sunday at the local county fair, and I'm determined to roll in with a working air conditioner. Our fair is the largest one in the state with a little over 500k in attendance (last year). Only thing left to do on the car before Sunday is a complete detailing and re-string the cargo net.

[bfloyd]

Looks like my "creative engineering" on the compressor actually worked. Just picked up my car from the local mechanic who did the evacuating and charging. NO LEAKS anywhere in the system, and it's blowing at a comfortable 43 degrees!

[Farrar]

Congrats, Barry!

[DMC5180]

Cool! (pun intended)

The next thing you'll need to look for is that evaporator housing drain is functioning properly. Puddle on the ground not passenger floor.


Dennis

[Jonathan]

http://www.carparts.com/details/Taylor_Cable/Spark_Plug_Wire_Loom/T6442709.html?TID=gglpla&origin=pla&gclid=CLDkh4-LxM4CFUUdaQodPYQACg

Those are for 10mm wires.
I think these were direct fit for the hoses.

I did some other stuff that required a mix of hole sizes. For those I used the 8 mm set and up sized a hole as required with a drill.


Dennis

"Spark plug wire loom" is what the website calls them. Right on. I'll keep my eye out for something like that. Thanks!