620 A/C compressor mount

[Gery]

I have read a lot of old posts about the difficulties of adding A/C to a l20b 620 truck, but I want to give it a shot.  I understand that the appropriate compressor bracket is very hard to come by.  If no one has one available, does anyone know of a type that can be modified?  Or, even a picture of what a picture or diagram with measurements from which I could fabricate one?  I’m assuming it is critical to anchor to the compressor to the engine rather than the frame to avoid mismatched torsion across the belt.  

Other ideas?

Thanks

 

[Gery]

Sorry, this was put in the wrong category.  I will try to move it.

[datzenmike]

I moved it.

 

I think the '79 was the first year with optional air con although dealers could install a kit for you. The '79 mounts a York pump where the L20B fuel pump is and uses an electric fuel pump similar to the 720 truck. There was a special frame to mount using the fuel pump studs. If you were not in California I would suggest making your own mount and put it where the smog pump is now.

 

 

 

[FrankRizzo]

"not in California" + The Peoples Republic of Santa Monica. Im pretty sure he will be taxed for A/C installation....

.

[Gery]

There seems to be a bit of legislation in place that allows for vehicles from 1976 to 1981 to be exempt IF INSURED as antique autos.  I’m counting on that since I just picked up this car and it is not CA smog compliant.  Fingers crossed.  So I may be able to put something where the smog pump is supposed to go.

[datzenmike]

The side of the block is drilled and tapped for smog pump and/or a compressor. My '76 710 had a pump there right under the distributor. The mount is a heavy cast iron thing but it also has the tensioner pulley on it too.

[AtomChurch]

If you want a stock installation (or as good as you could get Ac for the times then find the parts you need: Mike is right, he is a smart man. 

if you would rather just buy a kit.. look into vintage air. 

[Charlie69]

1980 720 L20B had AC you can get the compressor bracket and idler pulley from one of theses trucks.  The problem with this is the steering box on the 620 might be in the way.

Edited July 16, 2018 by Charlie69

[Gery]

All this is very helpful!  Thank you.

I’m not sure how to post a photo here but I put a picture on my profile.  Is that the piece I am looking for?

[Gery]

Wait, that is from a 280 z, so I doubt it.  That would be too easy!

[datzenmike]

That's the one. 280Z is still an L series engine.

[Stoffregen Motorsports]

Z car engines and truck engines do share a lot of parts, but the for-aft spacing is different, ie- the pulleys probably won't line up.

 

I would do everything I could to not have to use the York compressor. They are huge and very inefficient.  Have someone make you a bracket for a custom (modern) compressor. Any hot rod, racing or fab shop can do that kind of work, and there's no shortage of fab shops in SoCal.

[distributorguy]

If I'm not mistaken, you'd need the crank pulley from the 1980 720 as well, to line up with the idler pulley.  And the upper bracket.  I think there may have been a shift in the mount holes on the block as well for the bracket, so some fab work would be required either way.  Just start from scratch.  There are enough universal aftermarket brackets that its can't take more than 30 minutes to fab something basic, at least in a well equipped shop. 

[Bleach]

Can the main pully from a 280Z or 280ZX be installed onto an L20b? I think it would work. What I don't know is if the threaded holes on the L28 are the same as the L20b for the A/C pump. Although these days the 280ZX is not as common to find for parts, most of them did have air conditioning. Their pump goes below the intake/exhaust manifold so it would be where your smog pump is as stated before.

[Stoffregen Motorsports]

I know the 240Z has a completely different back spacing, so if you ran the crank pulley, you would also need the alternator brackets, the water pump and water pump pulley.

 

I also know that the 280ZX crank pulley is different from the 240Z pulley, but I do not know if the spacing is the same.

[Stoffregen Motorsports]

5 hours ago, distributorguy said:

If I'm not mistaken, you'd need the crank pulley from the 1980 720 as well, to line up with the idler pulley.  And the upper bracket.  I think there may have been a shift in the mount holes on the block as well for the bracket, so some fab work would be required either way.  Just start from scratch.  There are enough universal aftermarket brackets that its can't take more than 30 minutes to fab something basic, at least in a well equipped shop. 

30 minutes? This coming from the guy who said it would take him 3 hours to fab the custom intake manifold...?!

 

I would guess 6 hours, but that's me.

 

 

[distributorguy]

It did take 3 hours. Remember how I built the first manifold, then completely rebuilt it differently?  Actually it took 2 1/2 the 2nd time.  First time was a day, as I stated.  4 hours to make flanges, the balance to cut and fit pipes. 

 

It may take an hour to figure out what to make however?  Or I could sell the guy a 1980 setup off an L20b.  I have one with new bearings already installed.  

[Charlie69]

Contact Bonvo here on Ratsun his dad got him an L motor bracket for a Sanden 505 compressor.  This is a R12 compressor so you might also ask for the R134A compressor that is the conversion of the R12 505.

Edited July 16, 2018 by Charlie69

[Stoffregen Motorsports]

Sanden is relatively compact and there are a million and one aftermarket parts for them.

[Gery]

Again, many thanks for all the thought and advice you all generously provided.

I’ve replaced the cover photo on my profile with a engine picture with a red highlighted area. Is this structure a compressor?

 

[Charlie69]

Yes that is a York compressor that eats horsepower!

[Seeker > 620 KC]

By what I hear And understanding the “antique” insurance status is only available if you register the vehicle with CA DMV as a historical vehicle. This may also incur more yearly state fees and could also limits how much you can drive it per year to maintain historic vehicle status. I suggest confirming  this before eliminating your smog pump to install a compressor (pump) in its place.

 

AC was not installed by the Japanese Nissan factory in early 620’s. When exactly they started is not clear. Many state-side dealers were buying after-market US made AC units (under dash and in-dash units)  and installing them at their dealers or by local shops near them like ARA shops. Then the dealer sold these to car buyers as “factory AC.” None of these units were made in Japan despite having silver lettering on the AC switch control plates saying “Datsun.” This can be confirmed by looking at the compressor mount plates, fan squirrel cages, or hose ends. The compressor mounts are welded plate steel, the squirrel cages are stamped “Made in Ohio,” and the hose ends are slide-on with hose clamps. ,

 

Find a Datsun/Nissan published 78 or 79 620 factory service manual (NOT a Haynes, Chilton, or Motor’s brand.) Both year manuals have very good AC sections with exploded views of the 3 combined brackets (difficult to find in So Cal) it takes to mount the  heavy square vibrating original York compressor on the passenger side of the engine. The main bracket is cast iron and weighs 12 lbs! It must be bolted to two other smaller brackets in order to mount the York compressor. 

 

image by Bash Barker, on Flickr

 

 The York compressor was not mfg by Nissan but was the only compressor used by Nissan for orig 620 AC, and was included in the Datsun/AC kits assembled at the Japanese factory. Nissan was using Hitachi compressors in 

 

I have these and can share them but am just getting back the skills for posting pics, bear with me.I also have pics of various mounts. More in my next posts.

Edited July 30, 2018 by Seeker > 620 KC
Clarified a sentence or two.

[Stoffregen Motorsports]

Good info. Thank you.

[Seeker > 620 KC]

I'm responding from work, so I must post in chunks. Thanks for bearing with me.

 

I just checked the online version of the 1977 620 Datsun/ Nissan Factory service Manual and it too has a section on AC.

 

My understanding is the 620 Japanese Factory AC began sometime in 1976. But having to print service manuals in advance of the vehicle model production year, I don't know if they got the AC published Factory Service Manual (FSM) in the 1976 Datsun/Nissan version or not.

 

Tried to locate a 1976 620 FSM online without success. If someone has this manual and could confirm if it has a AC section or not it would narrow down and give proof to my understanding. Posting a pic of the FSM cover and table of contents would be ideal documentation, if anyone has those skills I seem to have lost or not kept updated.

 

Much appreciated.

 

 

 

 

[Seeker > 620 KC]

As for the York compressor and Charlie's statement of horsepower robbers...

 

those compressors were big, noisy, and created a lot of vibration.

 

And on a 620 that only produces about a 100 hp, they could bog the motor down under cruise some, but heavily at low speeds causing them to stall often because...

many of the aftermarket AC makers like Frigidaire (Frigiking and ARA) did not make as sophisticated AC units as Nissan, so they didn't put actuators that raised the idling RPM, etc. They also caused a lot of vibration at idle and low speeds, especially if the aftermarket brackets weren't secured well, or were stripped out on install by non Datsun shops. And the front seals often overheated and caused Freon leaks, on top of the leak causing slide-on hose fittings. This made a lot of 620 York owners give up on the complicated "modern" (at the time) AC and remove the compressors and leave them off their vehicles forever, leaving the lines, mount brackets, and condensers in the engine compartments and the evaporators in the dash... with no working fresh air vents after that! 

 

York got a seriously bad reputation like Edsel, some deserving, some not. But if maintained Yorks did a good job and lasted a long time. And they were the only AC option available on 620's and a lot of American cars for a decade or more. I believe Colour Box reasonably wanted AC in a hurry for the summer and just restored Factor AC using a York in her little Stanley 210. I can't wait to catch up with her and check it out. It will be a real flash-back to my Econo Motors Datsun Dealership days of installing AC in Riverside CA.

 

More on Sanden and Hitachi compressors and more modern ugrade installations in my next posts.

 

 

 

Edited July 20, 2018 by Seeker > 620 KC
Added Break-away pic of York Compressor