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Tue Jul 12, 2016 5:50 am

busdaddy wrote: any relay will close when the alternator starts making power on the charge light circuit

Good point, busdaddy. I think turning on my AC System power relay using the blue wire from the voltage regulator would give the same effect of delaying AC start until the engine is running. (might have to use a diode to make sure the current in that circuit flows the way it's supposed to, but it would certainly work)

To use the charge light circuit, though, I'm wondering if you'd have to use a high impedance solid state relay, vs a standard relay that uses a solenoid coil for the switching, to avoid changing the resistance of the charge light circuit? It apparently makes a difference, since I had to swap my charge light warning bulb from a 1.2 watt to a 2 watt so the light would go out, without having to rev the engine. I don't want to risk having to "wake up" my alternator again by changing something in the charging circuit, so that's the main reason why I thought adding the delay to the fuel pump circuit was a better option.

If anybody else uses the time delay switch method, be aware the polarity of your wiring matters. This devise is solid state, so current only flows one way. If it doesn't work, switch the wires and it will :D

Tue Jul 12, 2016 7:20 am

Since my '78 is running better and better, I can now start dreaming of utilizing it's compressor and installing AC in that bus!

I have an old underdash unit that was installed, I presume, at the dealer years ago.

Any reason to believe that the TDI's compressor and this under dash unit cannot be married to work together in harmony?

Tue Jul 12, 2016 7:25 am

You should be fine to run it, assuming it's in working condition.

Personally after doing the research on my end, I would not re-use any of the existing hoses or the condensers.

Save your hoses, you can get a shop to make new hoses from the old dims, they can also cut off the old fittings and weld them on to reuse 'em.

Mon Jul 31, 2017 4:25 am

Got a question about Peanut style compressor fittings for Denso compressors from another Samba member, so I thought I'd add some more pics of the various fittings I found at junk yards for others, who want to build their own custom systems.

What I found is that the aluminum block peanut fittings are slightly different for cars built in the 1990's, vs ones from the 2000's. The fittings I used for my bus were salvaged from 1990's era Honda's, Mazda's, and Toyota's, and my compressor was specified for a 1994 Toyota 4 Runner.

This pic shows my fittings already brazed onto my hose ends. I put some pieces of rubber hose over the tips of the fittings, just to protect them during the build process

The 2000's era fittings are a bit beefier than the earlier ones and also include a roll pin, presumably for more precise mounting and better sealing. I believe these fittings (below) came from an Isuzu truck and a Mazda car. (I needed to mix and match to get suction and discharge fittings with ports pointing in the right direction.

Here's the manifold that came from the Isuzu truck, but these will fit a lot of Denso compressors:

I also found a manifold from a John Deere tractor that allows the use of conventional style screw type fittings (Similar to Sanden), but this one would have required me to hack up my engine tin for hose attachment.

There's a company called Jensen Automotive that rebuilds Denso AC compressors, and they have new manifold gaskets to fit whatever manifold and fitting configuration you can find at your local automotive bone yard.

Sat Mar 31, 2018 12:12 pm

While my engine is out to repair a worn cam thrust bearing I had a rare opportunity to take a picture of the compressor mount and belt tensioner I fabricated for my AC system.

After two years and about 11,000 miles the system has performed excellent with zero noise or vibration. One small problem I did find was that the Honda power steering pump pulley that I modified to drive my AC compressor has a slight offset, so if you put it on backwards it will cause your belt to run off-center slightly. I found this out only after noticing my belt was not running perfectly centered on the idle pulley like it was when I first mocked up the system. The belt didn’t seem to mind this but I corrected the problem going forward

Sat Apr 14, 2018 12:30 pm

Will the :bay_white: OEM DPD Overhead Air Conditioning Evaporator Unit fit in a T2b KOMBI with a sunroof?

Was the Overhead Evaporator Unit ever installed in a KOMBI Westfalia "Los Angeles," model? The vertical hoses would have to clear the left side rear aft-facing passenger seat with storage unit and the right side sink overhead vent tube.

Are the Dealer Installed DPD Air Conditioning Installation Instructions available? I have not located any leads in TheSamba.com.

:vw: Thank you

Sun Apr 15, 2018 5:34 am

The DPD units covers an area beginning at the front sun visor clips back to about the front edge of the sliding door, so if the sunroof does not extend forward of this, then it should fit. I'm not familiar with all the T2 bus variations, but the front sections (where a DPD would install) appear identical on nearly all of them.

I also found there are several variations of the Overhead DPD units and the CCC ones, but they all cover the same basic footprint on the top of the bus.

No instructions exist, that I know of on the Samba, but there was a previous poster (rugblaster) on this thread that use to do the dealer installations, so perhaps he may know if anything exists.

Sun Apr 15, 2018 9:17 am

There's a few install sheets down near the bottom of this page: https://www.thesamba.com/vw/archives/manuals/heater_ac.php
The overhead unit covers the sunroof crank and hangs out over the hole in the roof a little, same applies for factory Westfalia pop tops. There was a unit available for campers that fit under the jumpseat with a duct that stuck up behind the drivers seat and blew fore and aft, and a similar one for 74/75 under the sink, rare but not impossible to find.

Sun Apr 15, 2018 7:48 pm

busdaddy wrote: ... There was a unit available for campers that fit under the jumpseat with a duct that stuck up behind the drivers seat and blew fore and aft, ... rare but not impossible to find.
I have one I'll trade for an under dash unit for early bay.

Mon Apr 16, 2018 6:31 pm

I have a sunroof bus and 3 different versions of overhead a/c units put in buses and NONE of them fit. The buttressing for the sunroof hole that goes off to the side near the back of your head behind the front doors interferes with their mounting. I suppose it could be possible to shorten the forward duct and make it work but me thinks an under dash unit is more reasonable.

Sat Jul 28, 2018 9:41 am

Took some of the old DPD manuals posted here on the Samba and modified the pics to create an updated electrical wiring schematic and AC System hose layout schematic. My son keeps hinting he wants the bus back again some day, now that it has Air Conditioning, so he needs a record of how it's built, in case he or somebody else has to maintain it one day.

Maybe this can also benefit the Samba community, if anyone else wants to salvage an old DPD overhead system.

Sat Jan 05, 2019 11:51 am

Does anyone know the freon and oil capacity for a 1973 VW Bus DPD under dash AC system? Also the belt size for the pulley? The system will now use R134a instead of R12 and a Sanden SD508 Compressor.

Updated wiring diagram for 1979 DPD under dash AC system, which is the same for 1973. Note most of the wiring is 12 and 10 gauge wire.

Changes from the original wiring:
1. The power load is now split between two 40amp relays.
2. AC compressor clutch pressure shutoff relay. The relay only activates when the pressure gets too low or too high.
3. The new VDO PM350 condenser fans are now wired in parallel instead of in series. Even though VDO PM350 fans are marine grade I recommend sealing off the brush access hole with Flex Tape or whatever you want to use. The vent holes on the shaft side are fine left open. That way rocks and other things will not get in the motor while you are driving.

The + 30 on the Thermostat relay is supposed to have a 40a fuse also. I forgot about when I made the diagram.

Evaporator and Condenser Relay location

You have to add about an inch to the left side on the condenser mounting bracket. That way the motors clear the floor.

AC compressor clutch pressure shutoff relay

Positive from the pressure switch to positive on the battery

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Sat Jan 05, 2019 2:24 pm

Looms, chafe relief, strain relief, wiring practices.

Tue Jan 08, 2019 5:36 am

TheOrangeBus wrote: Does anyone know the freon and oil capacity for a 1973 VW Bus DPD under dash AC system? Also the belt size for the pulley? The system will now use R134a instead of R12 and a Sanden SD508 Compressor.

You can check with Sanden on the Oil quantity, type, and viscosity they recommend; since you're now a custom install, I doubt any of the factory recommendations will be valid. Oils for 134a refrigerant come in multiple types and viscosities, depending on what your compressor requires. It's not just a one oil fits all scenario.

If you are using the factory V-belt pulley on the crankshaft to drive your compressor, be aware that it is an odd angle (like a 60 deg. V) compared to most newer compressor end V-belt pulleys, which are 40 deg. I'm not sure if you can run this way or not, or if 40 deg. crankshaft pulleys are available, but that odd mismatch between pulley angles is what led me to go with a 4 rib serpentine instead

Wed Jan 09, 2019 12:33 pm

69BahamaYellow wrote: TheOrangeBus wrote: Does anyone know the freon and oil capacity for a 1973 VW Bus DPD under dash AC system? Also the belt size for the pulley? The system will now use R134a instead of R12 and a Sanden SD508 Compressor.

You can check with Sanden on the Oil quantity, type, and viscosity they recommend; since you're now a custom install, I doubt any of the factory recommendations will be valid. Oils for 134a refrigerant come in multiple types and viscosities, depending on what your compressor requires. It's not just a one oil fits all scenario.

If you are using the factory V-belt pulley on the crankshaft to drive your compressor, be aware that it is an odd angle (like a 60 deg. V) compared to most newer compressor end V-belt pulleys, which are 40 deg. I'm not sure if you can run this way or not, or if 40 deg. crankshaft pulleys are available, but that odd mismatch between pulley angles is what led me to go with a 4 rib serpentine instead

I talked to my dad who has been an auto mechanic for 30 something years he said, " It's fine to run a V belt with pulleys with two different angles. Just as long as the difference is not too big. The belt will just sit deeper into one of them." The compressor I'm using requires PAG 100 I'm going to use TSI Supercool P100-32D PAG 100-Viscosity Plus U/V Dye Oil - 32 oz. I haven't been able to find any DPD factory recommendations

Wed Jan 09, 2019 4:59 pm

If you go back to page 4 (I think) of this thread, I talked about the V-belt fit. Yes, I think you can make a 40deg belt work on a pair of 60deg pulleys or vice versa and the belt will eventually wear and conform to the pulleys, but your problem will be pulleys of 2 different angles. You can choose a belt for either, but it will start with full surface contact on one pulley and just edge contact on the other. I suppose the belt would eventually wear to 1/2 surface contact on each pulley (half at 60deg and half at 40 deg), but in the heat of the summer, when high side pressures can get over 300 psi, you may not be able to get enough belt tension to keep it from slipping....

Glad to hear you found out your compressor takes PAG100. As for the refrigerant charge, I ended up with 60oz for my 3 condenser, overhead evaporator system, but you will just have to charge until your high and low side pressures are within range for the ambient temperature. Due to the long hose lengths from the engine all the way to the front of a bus, I think about 10psi above on the high side and 10 psi below on the low side is just about perfect for 134a. Maybe some of the smarter AC guys here can chime in on that one.

Wed Jan 16, 2019 11:00 pm

so where can I get a mount
or York mount for a Type 1/3 engine?

Wed Jan 16, 2019 11:30 pm

The DPD unit on my '71 ('71 vintage type 1 York compressor and '75 vintage overhead evaporator and condenser) used an odd-ball angle Continental solid belt (part number unknown) which unfortunately seems to have been discontinued. You can find a Continental toothed version of the belt, but it doesn't work (rolls over in the pulleys). Anybody have the correct Continental solid belt part number, or know of an equivlent?

Fri Jan 18, 2019 6:58 am

TheOrangeBus wrote:

These pics seem to confirm something I suspected about the original factory setup: The airflow through the condenser is from bottom to top, as it looks like the bottom louvers are pointed forward, and the shroud on top seems to indicate the fan's are pullers, instead of pushers. Am I seeing this correctly?

I set my system up the opposite way with puller fans on the bottom of the condensers. My system works excellent with the bus sitting still or at highway speed but I've always wanted to rig up a GoPro camera under the bus with small ribbons attached at various points on the undercarriage to see which way the airflow is really going at different speeds.

Sun Feb 10, 2019 5:13 pm

69BahamaYellow wrote: TheOrangeBus wrote:

These pics seem to confirm something I suspected about the original factory setup: The airflow through the condenser is from bottom to top, as it looks like the bottom louvers are pointed forward, and the shroud on top seems to indicate the fan's are pullers, instead of pushers. Am I seeing this correctly?

I set my system up the opposite way with puller fans on the bottom of the condensers. My system works excellent with the bus sitting still or at highway speed but I've always wanted to rig up a GoPro camera under the bus with small ribbons attached at various points on the undercarriage to see which way the airflow is really going at different speeds.

The original way the fans are pushing the air from the top to the bottom switch is how I have them. I have the condenser in the orientation that the manual says and that's the only way to mount it because of the inlet and outlet ports. They did it that way so when you are driving air gets forced up into the condenser, which helps keep some load off of the electrical system and the fans last longer. It is weird they designed it that way though.