Air Condition

[philip]

snip- Mine is a hybrid, part Nissan compresor (SD-508) part Jeep (everything else). It turns out the SD-508 was also used on the Jeep XJ's, Cherokee's (Mid sized Jeeps). -SNIP

Which compressor was ORIGINALLY on the SD22 ... before fitted into your Jeep?

83 Hitachi MJ-167


... or 1984 DKV-14B

[ecomike]

Philip,

I don't know, I was not there. I know the 85 Jeeps used a Sanden SD-508, and I thought the 82 Nissan used an SD-508, but I am no longer sure what Nissan used after looking at my FSM.

It may be that I ran across something showing the SD-508 replacing the Nissan OEM Hitachi/KIKI? compressor, but my memory is way too vaque on it now.

What I do know is that I have an SD-508 Sanden compressor mounted, attached this Nissan SD-22.

It is possible the A/C mounting brackets on mine were custom made to hold the original Jeep Compressor. I did not do the original power plant swap. I only bought it as project in progress chalenge that still had some customizaiton issues.

The A/C works, just not as cool as yours!

[philip]

SNIP-I don't know, I was not there. I know the 85 Jeeps used a Sanden SD-508, and I thought the 82 Nissan used an SD-508, but I am no longer sure what Nissan used after looking at my FSM. -SNIP-
The A/C works, just not as cool as yours!

A Sanden 508 generally ....


Condenser bigger is more important than the expansion valve. And filling in AIR with the R (including R134a) is no help. Learn why home refrigers do what they do.


Here is the original KIKI (Yoke - York) on SD22, 1982

[ecomike]

Well I have discovered a few things. The evaporator, expansion valve and the condensor with the added electric fan in front of it that I added last year, are more than adequite for my needs. The choke point, or limiting factor in my case is the compressor RPM.

The idle (A/C compresor) rpm needs to be nearly double what I have for the compressor to catch up with the rest of the A/C hardware to really cool well on a hot day in stop and go traffic.

If I sit in park and race the engine to about 1600 rpm the entire system cools quite nicely.

Guess I will just have to grin and bear it, as resizing the compressor/clutch pully and engine crankshaft pully is not on my agenda. Instead I will just downshift and keep the engine RPMS up higher.

[philip]

Well I have discovered a few things. The evaporator, expansion valve and the condensor with the added electric fan in front of it that I added last year, are more than adequite for my needs. The choke point, or limiting factor in my case is the compressor RPM.

Tell me what "A/C Technical" desided a much greatered compressor.

The idle (A/C compresor) rpm needs to be nearly double what I have for the compressor to catch up with the rest of the A/C hardware to really cool well on a hot day in stop and go traffic.

OR... you have not found that a check valve reed or more inside the compressor is defective.

If I sit in park and race the engine to about 1600 rpm the entire system cools quite nicely.

The just mentioned about the check valves, and/or too much air mixed into the refrigerant and/or the correct refrigerant is over pressure (or too low). MOST compressor check valve reeds get cracked by added refrigerant liquid through the Input with the compressor running too quickly. I should mention to you that having too much OIL inside the system will make your A/C weaken during lower rpm. LOTS of people do this as a "good idea".

[ecomike]

Well I have discovered a few things. The evaporator, expansion valve and the condensor with the added electric fan in front of it that I added last year, are more than adequite for my needs. The choke point, or limiting factor in my case is the compressor RPM.

Tell me what "A/C Technician" decided a much greater compressor.

Two of the A/C shop owner gurus that run the A/C online forum in Phoenix, AZ, that I have joined advised me of the Jeep OEM late 80's sizing issues (what was over and under sized on the OEM jeeps) that he said are well known.

I also gave him the run down on my Nissan/Jeep hybrid and he nailed it right off the bat as an RPM issue on my compressor, pulley sizing issue for my frankinA/C hybrid. I later confirmed it with a few simple tests.

The idle (A/C compresor) rpm needs to be nearly double what I have for the compressor to catch up with the rest of the A/C hardware to really cool well on a hot day in stop and go traffic.

OR... you have not found that a check valve reed or more inside the compressor is defective.

The compressor is brand new.

If I sit in park and race the engine to about 1600 rpm the entire system cools quite nicely.

The just mentioned about the check valves, and/or too much air mixed into the refrigerant and/or the correct refrigerant is over pressure (or too low). MOST compressor check valve reeds get cracked by added refrigerant liquid through the Input with the compressor running too quickly. I should mention to you that having too much OIL inside the system will make your A/C weaken during lower rpm. LOTS of people do this as a "good idea".

There is no air in my system, only the correct amount of R-134a and PAG oil.

From the looks of it this compressor and mounting bracket system was custom installed on this SD22 to match the Jeep foot print under the hood before I aquired it. The old and new compressor is a Sanden Model #508. I don't recall as it's been over a year now, but does that cross over as the replacement for the Hitachi Yoke VR4709 as well? The Jeeps did came standard with the Sanden 508's. The hose connections on mine are a bit different from the SD-22 FSM pictures and the ones posted here so is the clutch.

Also, the Condensor outlet temperature is nearly ambient on mine (like within 5 degrees F of ambient under full load) with all the fan cooling I have on it, so I don't see how the condensor could be called undersized on mine! Keep in mind I have an XJ jeep condenser, not a Nissan 720/SD22 pickup truck condenser.

[philip]

OR... you have not found that a check valve reed or more inside the compressor is defective.

The compressor is brand new.

Never believe that brand new is good. In past, I've found a couple of new failures.

There is no air in my system, only the correct amount of R-134a and PAG oil.

But you did not check the amount of oil in the condenser (which can be too much) and/or too much oil in the evaporator.

I don't recall as it's been over a year now, but does that cross over as the replacement for the Hitachi Yoke VR4709 as well? The Jeeps did came standard with the Sanden 508's.

The "same looking" Sanden do look like the same physical but ... are not. Look at the piston/physical different. your "508" appears to have the largest pump.

The ear/ear reach is 60mm (2-3/16") on my VR4709.

One thing you mentioned is the drive pulley. The SD22 has a smaller crankshaft pulley for A/C than the pulley driving the water pump and alternator. Now from your Jeep, I can only imagine the crankshaft pulley would an 1:1 or maybe 1+:1 (over drive faster the a/c).

[ecomike]

OR... you have not found that a check valve reed or more inside the compressor is defective.

The compressor is brand new.

Never believe that brand new is good. In past, I've found a couple of new failures.

Yep.

There is no air in my system, only the correct amount of R-134a and PAG oil.

But you did not check the amount of oil in the condenser (which can be too much) and/or too much oil in the evaporator.

No, but last time I checked new condensers are not shipped with oil in them, LOL. All kidding aside, the compressor, hoses, drier/filter/accumulator, LP pressure switch, and condenser were all brand new. I only reused the expansion valve and evaporator.

I don't recall as it's been over a year now, but does that cross over as the replacement for the Hitachi Yoke VR4709 as well? The Jeeps did came standard with the Sanden 508's.

The "same looking" Sanden do look like the same physical but ... are not. Look at the piston/physical different. your "508" appears to have the largest pump.


One thing you mentioned is the drive pulley. The SD22 has a smaller crankshaft pulley for A/C than the pulley driving the water pump and alternator. Now from your Jeep, I can only imagine the crankshaft pulley would an 1:1 or maybe 1+:1 (over drive faster the a/c).

I will look into this later, maybe take and post some dimensions and photos too.

[ecomike]

Turns out the prior owner never reconnected the Jeep vacuum lines to the Nissan Vacuum pump source when they installed the SD22! They did connect the Brake Vacuum booster, which is partly why I missed this problem, but not the A/C vacuum tubing. So guess what? With out vacuum the vacuum operated A/C & Heat ventilation blend doors DO NOT FUNCTION! In my case this means my A/C when set on MAX cool was still processing 100% outside hot humid air!

With the MAX air door shut and only inside air recirculated though the A/C evaporator coil it will put me in a deep freeze, and that is with R-134a in my system, in Houston, TX.

I got the vacuum lines connected to the Nissan vacuum line and all the damper doors and actuators except one is working now. I am on the hunt for a replacement actuator for the one bad Jeep actuator now.

This things cools great now!

[philip]

Turns out the prior owner never reconnected the Jeep vacuum lines to the Nissan Vacuum pump source when they installed the SD22! They did connect the Brake Vacuum booster, which is partly why I missed this problem, but not the A/C vacuum tubing. So guess what? With out vacuum the vacuum operated A/C & Heat ventilation blend doors DO NOT FUNCTION! In my case this means my A/C when set on MAX cool was still processing 100% outside hot humid air! -SNIP- This things cools great now!