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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Tue Mar 08, 2016 10:36 am Post subject: Re: DPD Air Conditioning for type 2 bus? |
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BTW - can anybody explain how you add (user xxx) quotes to a post for replies? I've read and appreciate everyone's feedback so far, just not sure how answer them all....
Thanks udidwht for the clarification on the direction of your condenser louvers. That tells me dpd also figured out the best way to route air through the condensers is over the top of the frame rails, through the condenser and out the bottom. |
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samwise Samba Member
Joined: May 04, 2010 Posts: 611 Location: North Salt Lake, Utah
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Posted: Tue Mar 08, 2016 2:26 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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69BahamaYellow wrote: |
...I should also add that I've corresponded several times now with Ed from Gilmore enterprises (super nice guy and very helpful), and if I had known they were working on a split front/rear AC system for a bus, I'd have never taken on the dpd refurb. but as it is, my family won't ride in the bus in Texas heat with front AC only, and it goes against my perpetual DIY nature.. |
Interesting....
69BahamaYellow wrote: |
69BahamaYellow"]BTW - can anybody explain how you add (user xxx) quotes to a post for replies? I've read and appreciate everyone's feedback so far, just not sure how answer them all.... |
Click the <Quote> button at the top right of the post you want to quote in your reply. It will automatically add the information. _________________ Ben
1979 7-passenger bus
Harvee the Wonder Bus' pics |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Sun Mar 13, 2016 6:53 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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Thanks for that, Samwise.
So I finally got some aluminum tube, beadlock hose barbs, and braze on service ports to make my compressor fittings. I had to start by recycling some used "peanut style" compressor ports, since I can't find anyplace that sells them new. These things are perfect, because they work in very tight spaces. Just cut off the old hose, then drill out what's left and you're ready to braze in new tubes. The aluminum bends very easy, so complex turns are easy.
The secret to making beautiful welds on aluminum is to use this specialty brazing rod that the AC hose folks re-sell. Just slowly heat up the joint with a propane torch and brush the tip of a braze rod across the joint, and it flows right in
And here's the finished product
Now I just have to route the rubber hose, cut to fit, and take these to a hydraulic shop to crimp on the fittings. |
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skills@eurocarsplus Samba Peckerhead
Joined: January 01, 2007 Posts: 16801 Location: sticksville, ct.
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Mon Mar 14, 2016 7:14 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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[quote="skills@eurocarsplus"]good job. but they are available
http://www.ebay.com/bhp/ac-compressor-fittings
Thanks for pointing that out. Yes, there are a few peanut style fittings available for the Sanden compressors, but I've never seen any of the side exit style available brand new. I'll post some pics of the installed hoses, once I get them back from the hydraulic shop, but the side exit fittings make all the difference with the limited space. |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Thu Mar 17, 2016 7:12 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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Making some progress on installing the hoses after I got some more bead lock fittings crimped on. The return line from the evaporator to the compressor is 15' long! Now that the compressor hoses are installed, I can reinstall the engine tin for good
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skills@eurocarsplus Samba Peckerhead
Joined: January 01, 2007 Posts: 16801 Location: sticksville, ct.
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Posted: Thu Mar 17, 2016 7:23 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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looks good! not sure if it's the photo, but will you be able to get the low side collet from the a/c machine on there? looks pretty tight.
I would probably pull a vacuum on the system for 30-45 minutes. if you wanted to go crazy, you could purge with nitrogen to check for leaks/help push out any moisture. may want to add some dye to the system when you refill it. you can buy a decent kit from snap-on that comes with the black light, glasses and dye
it will be worth it when you're done! _________________
gprudenciop wrote: |
my reason for switching to subaru is my german car was turning chinese so i said fuck it and went japanese....... |
Jake Raby wrote: |
Thanks for the correction. I used to be a nice guy, then I ruined it by exposing myself to the public. |
Brian wrote: |
Also the fact that people are agreeing with Skills, it's a turn of events for samba history |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51057 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Thu Mar 17, 2016 7:24 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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Exciting!, did you use rubber hose all the way to the front?, or hard lines with short rubber sections where it flexes by the engine? _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Fri Mar 18, 2016 4:45 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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skills@eurocarsplus wrote: |
looks good! not sure if it's the photo, but will you be able to get the low side collet from the a/c machine on there? looks pretty tight. |
It looks like a tight fit, but both collets fit the service ports with no problems. That is actually the first thing I checked when I made the high side compressor connection, but what an easy thing to overlook, so I'm very glad you notice things like that too, Skills |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Fri Mar 18, 2016 4:53 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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busdaddy wrote: |
Exciting!, did you use rubber hose all the way to the front?, or hard lines with short rubber sections where it flexes by the engine? |
I used rubber hose all the way to the evaporator. I really wanted to use aluminum tube most of the way, but you can't really run hard lines without significant disassembly of the bus. The other problem is that you need to have a rubber line from the floor to the sealing, because you have to attach the hose to the evap and then lift the whole unit to the roof; since you've also got to have rubber from the compressor to about the rear torsion bar tube to accommodate engine movement, you might as well run rubber all the way. One single rubber hose is also way easier to install. I only had to drill (2) 1-1/8" holes in the driver side front fender well; the rest of the holes were already there, so this install is almost completely reversible. |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Fri Mar 18, 2016 5:04 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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skills@eurocarsplus wrote: |
if you wanted to go crazy, you could purge with nitrogen to check for leaks/help push out any moisture. may want to add some dye to the system when you refill it. |
When I get everything together, my plan is to pressurize the whole system to 150psi with compressed air (using an old receiver/drier), and then see how it holds overnight. I'll probably also use soapy water on all the connections to look for tiny leaks at the beadlock crimps. this is where I've found leaks in the past, but I paid close attention to the guy doing the crimping this time to make sure he used the right dies for the right hoses. using the wrong ones will make leaky connections.
If it's all leak free, I'll put a new receiver drier in place and pull a vacuum and hold overnight, before the final deep vacuum/charge |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Mon Mar 21, 2016 7:48 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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This weekend I mocked up the condenser fans and made a fan cowl to help pull air across the most surface area. The fans are pretty light weight, so I made the cowl out of a 3' x 3' piece of anodized aluminum sheet from Home Depot.
The basic layout
This sheet is only .019" thick stock so you can form it with just a workbench, a board and hammer
Tin shears and a hand seamer were used to finish the job. In the right light, it looks like copper, but that's just the anodized finish
And finally this is the finished install. The fan's are actually above the bottom of the frame rail on the right side, but for the condenser on the left (driver side), it will probably hand below the frame rail about 1/4", due to the existing tubing for the clutch and hand brake cables. Can't figure out any way to re-route those easily, but I think the left condenser will still be out of harms way.
more to come |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Thu Mar 24, 2016 7:33 pm Post subject: Re: DPD Air Conditioning for type 2 bus - Hoses Installed |
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Here are a few more pics of the hose routing. Total of 3 holes drilled so far (2 in the fender well for the #6 and #12 hoses), and one in the top of the frame rail. I debated for a while whether or not to route the #12 LP hose through the top of the frame rail or through the existing 1.25" hole just above it to the left, or through the jack support like dpd did back in the 70's. In the end, There's plenty of structural steel above the frame in the front fender well, so I decided routing through the frame rail (and drilling a hole through it) had a negligible effect on structural integrity of the bus, and it gives the shortest distance back to the compressor, with the most protection. I'll use the existing hole above the frame rail to route the high pressure #6 hose from the condenser(s)
After driving the bus around some more, I've noticed another problem I need to fix. There is a ton of hot air that comes out of the heater flapper valve (just out the back of the heat exchanger), and that is what's cooking my compressor, and now the AC hoses. The radiant heat from the muffler is almost negligible compared to the waste heat that dumps out of the flapper valves. I remember there use to be some kind of pipe connected to this to get that heat further away from the engine bay, but I can't remember what it looks like. If anybody has a picture or knows what they're called, maybe I can buy some used ones for left and right sides or make something. In the mean time, I've put a heat shield around my AC hoses.
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skills@eurocarsplus Samba Peckerhead
Joined: January 01, 2007 Posts: 16801 Location: sticksville, ct.
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Posted: Thu Mar 24, 2016 7:46 pm Post subject: Re: DPD Air Conditioning for type 2 bus - Hoses Installed |
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I had removed an overhead unit on a bus some time ago, and they just used an axe and a big old wad of dum dum/butyl tape/ monkey poo whatever you want to call it.
where did you find those grommets? looks like a nice clean install _________________
gprudenciop wrote: |
my reason for switching to subaru is my german car was turning chinese so i said fuck it and went japanese....... |
Jake Raby wrote: |
Thanks for the correction. I used to be a nice guy, then I ruined it by exposing myself to the public. |
Brian wrote: |
Also the fact that people are agreeing with Skills, it's a turn of events for samba history |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Thu Mar 24, 2016 8:24 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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Coldhose.com has the hose grommets. They advertise them as suitable for #6 through #10 hose, so they're a very tight fit for #12 hose.. |
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airschooled Air-Schooled
Joined: April 04, 2012 Posts: 12686 Location: on a bike ride somewhere
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Wed Mar 30, 2016 7:12 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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asiab3 wrote: |
"Heat dump tubes" will be your magic words. Buy these while you can: |
Thanks for that! Looks like the tubes I remember. I may try to make some first out of old exhaust pipe, before trying to buy those OEM tubes.
I also decided to experiment with an airfoil design for my front condenser, so I don't have to install another fan. The idea here is to create a low pressure zone on the bottom to suck air through the top through the front beam. It's a work in progress so far, but I think it has potential
Top View
The Low Pressure Zone is created by the large diffuser at the edge of the condenser. It hangs down 2.5" from the bottom of the frame rails installed, but it's in-line with the front jacking points and close to the front wheels, so I don't think I'll be hitting it on anything when I'm off road or camping.
Condenser Bottom View - Entire Bottom of condenser is enclosed
Condenser is installed at roughly 30 degrees angle leaving an open slot between the condenser and the front floor about 6 inches at the leading edge. I believe air can flow directly under the front bumper and through the front beam between the torsion bar tubes and straight into the top of the condenser. the trailing edge of the airfoil has a laminar lip at a much steeper angle to force more air down and create a larger low pressure zone.
Finally, I could connect all the hoses to the receiver drier. This one has 2 sensor ports, so I can install pressure switches to control the condenser fans. I'm thinking I'll use one switch that cuts in at 90 PSI to run the primary condenser fans and the second switch will cut in at 250 PSI to run the secondary condenser fans. In theory, I'm thinking that at lower air temps, the high side pressure won't be enough to turn on the secondary fans, but they'll come on normally in hotter weather.
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Fri Apr 08, 2016 7:52 pm Post subject: Re: DPD Air Conditioning for type 2 bus? |
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I finally got all 3 condenser's mounted and finished connecting the Receiver Drier. With this setup, I've got almost 500 cubic inches of volume from modern parallel flow condensers to match up with the 412 CI evaporator. With condensers, too much is better than not enough.
This is the complete DPD Overhead unit with evaporator, switches, and wiring installed. I really wanted to replace the old school 3 position fan switches and resistor packs with a modern Pulse Width Modulated switch for fully variable speed control of the evaporator fans, but I got impatient and just re-installed the old stuff. I lined the inside air channels with polystyrene and foam insulation, so the cold surfaces would not condense water after the system is shut down. I've heard from a few others that have working overhead DPD units, that they can be prone to drip condensed water out of the vents in humid climates, because the plastic was not very well insulated. I definitely won't have that problem now.
Installation of the overhead unit was a surprisingly easy 1 man operation. I was dreading this job, since the completed unit weighs about 40 lbs. and the AC lines are pretty stiff, so they have to be connected with the evaporator positioned almost at roof level. To do this, I removed the front seat headrests and laid a small piece of plywood across the top of the seats and the dash to set the DPD unit on, so I could connect the HP and LP AC lines and the wiring, then lift it up 1 corner at a time to install mounting screws. Last step will be to install the cover over these hoses.
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Sun Apr 17, 2016 5:11 am Post subject: Re: DPD Air Conditioning for type 2 bus - success |
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It's ALIVE!! Yesterday was a very happy day. After finishing up all my wiring, I pulled a deep vacuum on the system with a rented pump and charged up my system. Yesterday was 75 deg. F, and I was getting 43 deg. F vent temps, and measured the condenser air outlet temps at around 106 deg. F, so I'm getting a nice 30+ deg. difference on both the hot and cold sides, but what I'm most impressed with is how much cold air this dpd overhead unit produces. The evaporator fans pull about 12 amps on full blast. I don't know how many CFM I'm getting, but it has no problem blowing cold air all the way into the trunk area with just the 2 rectangular rear vents, and it will flat out freeze you out of the front seats. Of course, there's a big difference between 75 deg ambient days and 100 deg days, so the real system test is yet to come. My four 7" condenser fans pull just over 10 amps, but they also remove a ton of hot air.
The condensate drains were streaming (not just dripping) water the whole time it was running, so I'm glad I put so much insulation on the inside air handling unit, when I put that back together, or I can see how the whole thing would just sweat condensation from the cold plastic.
I'll post pics soon, but next step will be to work on an idle speed compensation system. Right now, the compressor pulls the engine down about 200 RPM at idle, so I've just increased my idle speed a little to compensate. I'm thinking about just piping in a small solenoid air valve between the S pipe and the brake booster port in my engine manifold that opens every time the compressor clutch engages. With an FI engine, that should be the easy way to step up the idle as needed. |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 535 Location: Talbott, TN
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Posted: Tue Apr 19, 2016 7:00 am Post subject: Re: DPD Air Conditioning for type 2 bus - Need AC Expert Advice |
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So on Sunday, I took the bus out for a drive in a pouring rainstorm to further test out my AC. It was about 80 deg. F and obviously 100% humidity. Ordinarily, this would mean fully fogged up windows in a matter of minutes, but with the AC running on low, there was no fogging and a de-humidified comfortable cabin with 3 adults. I actually had to run a combination of AC and heat, since even on the lowest setting, it gets too cold.
Now for some questions; hopefully some of the AC experts out there can offer some advise. so far, I've had to put about 60 oz of r134a in it to get high side pressures of about 175PSI with a low side pressure about 30 PSI. This was at ambient air temp of 77 deg F on Saturday, when I charged it up, and the engine was running at idle. Inside vent temps were 46 deg F and condenser outlet air temp was about 106 degF with all 4 condenser fans running. Since I've got 3 condensers connected in series, I measured the outlet pipe temp. of the 3rd condenser at about 115 deg F to adjust the refrigerant levels. I started with about 24 oz of refrigerant, but this gave low side pressures down below 10 PSI at idle, so I kept adding refrigerant to get the low side up, while I watched the high side pressure to keep that below about 185 PSI. Based on my pipe temperature of 115 deg F at the Condenser # 3 outlet, it appears I still need to add a little more refrigerant, but 60 oz already sounds like I've got too much in it. Does anybody else have any experience charging systems with multiple condensers? Here's a few pics to show the additional work done:
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