DPD overhead A/C in an early bay

[scrivyscriv]

I have some A/C info and photos in my bus thread but I thought I'd start a standalone thread on this..

So a little over a year ago I picked up this 1971 Riviera camper bus.. ended up rebuilding the engine as soon as I got it.

Well it gets hot down here in lower Tennessee.. hot and muggy.. I drove it all year, and when the weather started to heat up this summer I got to thinking about the DPD overhead unit I had saved in my shed. It came from a '72 project bus that never made it off the drawing board..

Inspiration hit.. I ran to my shed, grabbed all the parts and carefully gutted the main unit down to a shell to check fitment with my Rivi pop top:

I'll lose a few inches of pop top access but the unit won't block my corner latches.. good to go!
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Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.

[scrivyscriv]

The hardest part about fabricating an A/C system in the bus, hands down is compressor mounting. There are numerous evaporator options.. some overhead units, some underdash, rear overhead mount - you've got options.. but when you start looking at what it takes to bolt up a new compressor, the game changes.

I have a rebuilt 1641 mostly all-stock engine (details in my sig if you care).. I'm big on making things look and work like the factory did it, from using robbed color-coded harness wire on repairs and installs, repurposing VW switches to control add-ons, etc. This is one huge deviation. the compressor will NEVER look like VW put it on, because the type one engine was simply not designed with ANY accessory drive in mind except the generator/alternator.

So.. still working on my compressor mounting, but here's what I've come up with:

This is a standard type one mounting bracket meant for a York compressor. It bolts to the distributor hold down stud and the upper #4 exhaust stud, and is by far one of the simplest designs around. Downside is I've heard of a guy whose distributor stud pulled out while using this style.
There are several other styles.. Antonio Trejo sells a VW Mexico mount bracket with integral idler pulley, Gilmore has his own bracket, I've seen a Thing bracket that works too..
I'll post more on the mounting once I get some parts fabbed up but it looks like I may be fabbing my mounting brackets from 1/4" steel to get a 100% custom setup.

The compressor you'll find in mid '80s Vanagons running the same evaporator is a Sanden 709 series.. they ran a smaller SD-508 compressor in early vans, but I think the evaporator can handle a bigger SD-709, and I'm running one of them. The biggest downside to oversizing the compressor is excessive clutch cycling.

Vintage Air sells a 'monster condenser' that I went with. It's 16"x28.5"x1" and the sales and tech guys both tell me it's capable of running two or three of Vintage Air's dash units, or a split A/C system. Nobody was willing to come up off any information on sizing the condenser to the evaporator other than vague generalities, and I think it's a mix of guys genuinely not knowing and some guys not being interested in helping you since you're not buying "THEIR" kit.

You say "VW Bus" and all of a sudden the friendly salesman clams up and the call goes nowhere. I had several sour grapes phone calls with Vintage Air and Nostalgic both.. their literature claims to be all about engineering A/C solutions but their phone support clearly isn't on the same page with the lit. I only called them since I had planned on giving them my business, and I ended up grudgingly opening my wallet to Vintage via Summit racing. I don't believe in asking for free help and support but they didn't want my money unless it was to buy a whole kit. So enough about them..
_________________
Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.

[scrivyscriv]

Here are some system specs.. the DPD overhead evaporator measures approx 25"x4"x4" for about 400 cubic inches of actual fin area.. it's huge.

to complement the evaporator, I got to looking around and the Vintage Air monster condenser seemed like the best bang for my buck.. at about $180 it's not inexpensive, but if you're ebay price shopping make sure you take the core thickness into consideration. Most units are only 3/4" thick.. the VA unit is a full 1" and that's a HUGE difference in surface area. Buyer beware!

Many of the kits I've seen involve a main plus a sub cooling unit.. Although I can't imagine any company including something that isn't absolutely necessary to the system's functionality, I do think I've got enough surface area and airflow to use just this one unit. If I'm wrong, no problem, I'll hang a 2nd unit for next summer.

Also.. I went ahead and spent the extra on a decent entry level Spal fan. Had to be conservative on my amp draw since I'm only running a 55A alternator, so the watts/amps were my main deciding factor, next to CFM numbers. I chose the Spal IX-30100400 16-inch puller to go underneath the condenser, with a shroud I'll fabricate shortly.

For electric distribution, my key factors were
A- ease of installation, neatness
B- ability to remove with little to no damage
C- durability

so I ended up with an Amazon.com relay/fuse sub panel. I hate it, it doesn't come with a fuse bus bar which is a big hassle, but does include all the connectors you need to wire everything and is a clean, neat install.

I just HATED the thought of hanging wires off a relay or even using a hanging relay with integral mount.. they work fine, but it's visual noise and I can't stand it.
_________________
Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.

[skills@eurocarsplus]

[scrivyscriv]

Rebuilding the evaporator and overhead unit was the easiest part.. I repaired the typical housing cracks with Permatex plastic weld and fiberglass cloth.

Then I flushed the evaporator core multiple times with MEK, followed by an isopropyl alcohol rinse, static leak check, and a nitrogen purge:

Fans were next. I pulled the squirrel cages off one motor, found it wasn't worth the effort and possibility of breaking something, and cleaned and oiled both motors. Amp draw was about 9-10A full speed and neither had any excessive draw, so no issues there.

Moved on to the housing, with cracks repaired.. I cleaned and shot the pieces in multiple light passes of epoxy primer, followed by a PPG single stage white polyurethane:

I really don't like to paint plastic, because scuffs show up and there's nothing you can do but touch them up.. can't buff or sand any of it because it's a textured plastic and you'd only ruin the whole part. It is what it is...

Finished with a NOS thermal expansion valve, a ton of cork tape, and most of a whole roll of reflectix:

_________________
Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.

[scrivyscriv]

[scrivyscriv]

Last photo dump for the time:


EDIT UPDATE PIC

mocking up compressor in engine bay. Looks like the left fan shroud leg will have to move over to the side of the shroud. Really hate to do it, but I've got something in mind that will look better than the type one a/c kits that have you cut off the leg, screw a patch over the hole, and gook a hideous attachment on the side.

EDIT UPDATE PIC

I may or may not have this done in time to use this summer...

I'm doing this for me, not for anyone else, not for props or instagram likes, or some sort of delusions of grandeur.. I hope someone can pick up some of this, and get more people realizing that air conditioning really is something in range of the methodical home mechanic.
_________________
Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.

[skills@eurocarsplus]

well, go big or go home

you will 1000% LOVE the a/c. it will make you giggle like you just saw your first booby, and know its wrong
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[scrivyscriv]

[69BahamaYellow]

Nice work so far Robert. Glad to see you started a separate thread, so this A/C stuff is easier to find in search

I see you are using PWM fan motor controls in your evaporator; that's a good choice. I wanted to go that route in mine, but just got impatient and re-used the old 3 speed switches and shunt resistors. Well that, and the fact that most of the PWM controllers I found on eBay were made in China was another reason to resort to tried and true....

I also found that the front vents will loose air out the top of the evaporator housing plastic (at the headliner), if you don't seal it up tight. I used a piece of 1/4" polystyrene foam taped to the top of my unit with aluminum A/C duct tape, and it doesn't leak a bit (making the front vents much more powerful), I also put some fiberglass insulation on top of that.

If you run out of power from your 55 amp alternator, don't sweat it. There are lots of high output options for a type 1 motor. My DPD system pulls around 26 Amps at full blast (I bet you'll be pretty close to that also), and by my math, that was too much for the stock 55 Amp alternator. If you also run the lights, and wipers simultaneously, which you will do often, since the AC does an outstanding job keeping all the windows fog free in a muggy rain storm, you'll need to bite the bullet and upgrade your charging system. None of the water cooled guys have that problem

Keep posting!

[69BahamaYellow]

Forgot to add:

If the hoses to your rear facing vents are too short (like mine were), I found that using a heat gut to warm them up will let you stretch them out about 2 extra inches so you can get them snugly inside that black plastic housing and hold them in with a few short screws.

[kooper271]

Great thread! My 77 came with the stock DPD system, but I'm planning on trading out my old compressor, lines, etc for a new system while keeping as many of the DPD parts as I can.

I know next to nothing about AC systems, so this seems like a good place to start. Thank you!

[markd89]

Nice work and subscribed!

Looking forward to hear about the performance on a summer day
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78 TDI Sunroof Bus
Los Angeles

[markd89]

[kooper271]

Question:

Where did you find a NOS thermal expansion valve?

[skills@eurocarsplus]

it's standard issue on units of that era. they can be had easily.
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[kooper271]

Thank you.

My 77 came with the DPD system. I have all of the original components. Do you think it would be worthwhile to keep the DPD overhead evaporator and replace the compressor and condenser?

[scrivyscriv]

I can't answer that yet but I will let you know up front you're going to open up your wallet and your clock whether you get the original unit working or go with a pre-fab unit like Gilmore or Ice AC. There is a ton of fab work involved making your own stuff work.. I'm not a pro car guy at all so some of this stuff is new to me or just really rusty, plus it depends on how "nice" you want your system to look.. I have two or three hours alone in moving my engine shroud left heater fan outlet over to make room for the compressor.. Maybe about the same in fabbing up the compressor mount, and I'm still not done with either.

Once I get my fans blowing cold air I'll let you know what I think
_________________
Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.

[kooper271]

[scrivyscriv]

My setup is specific to doing the install on an early bay so my compressor setup is 100% different from yours.. They make sanden to York compressor mount adapters but I don't know if they would fit a type 4 engine.
_________________
Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.