Differences in the factory Denso R-134a and the factory Denso R-12 A/C systems
 

I figured I would start a new thread to dig into some of the changes between the 95+ R-134a Denso A/C system and the 93-94 R-12 Denso A/C system.

My guess initially was that they were similar enough to only have minor revisions done. It looks like the majority of the changes could be minor; that or the part catalog doesn't show them properly here.

The compressors have different stickers for certain but the part catalogs are near identical. Is it possible that perhaps it's just that they are pre-loaded with different oils (as DaleClark mentioned could be possible in another thread: https://www.rx7club.com/3rd-generati...tions-1136880/)?

Has anyone noticed a difference between the two systems that they can catalog here? It may be that they only changed the oil in the system and perhaps later on the o-rings?

1993-1994:
https://cimg7.ibsrv.net/gimg/www.rx7...9afccd8e54.jpg
1995+:

https://cimg0.ibsrv.net/gimg/www.rx7...643d525ed3.jpg

Page 2?

1993-1994:
https://cimg7.ibsrv.net/gimg/www.rx7...3bf42b8bd3.jpg
1995+:
https://cimg5.ibsrv.net/gimg/www.rx7...e9d7ae80e3.jpg


Also, we can compare the Denso compressors:
1993-1994:
https://cimg8.ibsrv.net/gimg/www.rx7...482378da65.jpg
1995+:
https://cimg0.ibsrv.net/gimg/www.rx7...95c4a50c80.jpg

I found a catalog for the 93-94 evaporator as well but I have not found a 95+ one just yet. I have read that it's possible (via sc0rp7 https://www.rx7club.com/3rd-generati.../) they had different expansion valves, so I would be curious to see if this is accurate or not.

https://cimg0.ibsrv.net/gimg/www.rx7...dbf4ecbcd9.jpg

You would think the condenser would be more efficient on the R-134a systems, to account for the fact that R-134a is not as good of a refrigerant.

I have a 134a compressor in my attic, I'll try and get a pic posted of the back of it, it shows the 134a designation and has the ND part number, may be helpful to compare.

Also, I think the 95's still had the separate MANA and Nippondenso AC systems, or am I incorrect on that?

Dale

You would think so, but it doesn't look like they were different at all.

They did still offer separate Denso and MANA systems, at least according to the parts catalogs.

Denso 94
Hose high Fd15-61-461
Hose low fd15-61-462
Compressor 94 ND FD15-61-450
Condenser FD15-61-480
Evaporators FD15-61-J10
Exp valve Fd15-61-j14
Drier FD15-61-500




MANA 94
Hose high FD01-61-461
Hose low FD01-61-462a
Condenser fd01-61-480a
Compressor FD01-61-450
Exp valve FD01-61-J14
Evaporator FD17-61-J10
Drier FD01-61-500


Denso 95
Hose high FD15-61-461
Hose low FD15-61-462
Condenser F110-61-480
Drier FD15-61-500
Compressor FD15-61-450
Exp valve FD15-61-J14
Evaporator FD15-61-J10


MANA 95
Hose high FD31-61-461
Hose low FD31-61-462
Condenser FD31-61-480
Drier FD16-61-503
Compressor FD31-61-450
Exp valve FD31-61-J14
Evaporator FD17-61-J10


So there is 95 Denso and MANA systems and it does look like they stuck with the same condenser for the Densos in 95. Different part number for MANA but that could be administrative not necessarily a change in design.


Dale

https://cimg9.ibsrv.net/gimg/www.rx7...0fddc05be.jpeg
https://cimg4.ibsrv.net/gimg/www.rx7...6193185f2.jpeg


Pics of my R134a compressor. I THINK it was from a JDM car, bought it off Ebay on a whim some time back. Not sure what year or anything it's from.

Dale

It's still a TV14 compressor, but the switch on top is different. I wonder if they just removed the ability to remove the harness, or if its a different switch somehow.

I did get a chance to measure the temperature of my A/C vents this week in my R-12 Denso system converted to R-134a. It looks pretty comparable to R-12 in my opinion (95F ambient temperature).

https://cimg9.ibsrv.net/gimg/www.rx7...c62652d8c4.jpg

Hi, I think this may be a bit off topic... I have a 95 Mana system, the compressor leaked and was replaced with an aftermarket 4 Seasons AC Compressor Part Number 57367 which was a direct fit (but it leaked, so I'm looking for another replacement). I tried to reverse search that part number and it shows that the compressor also fits a Miata (94-04) and Toyota Tercel (94-96). Is anyone able to confirm the OEM 94-04 Miata compressors fit these cars? I had alot of trouble sourcing a new or reman compressor for my 95 mana.

This thread shows someone else using that same compressor/part # that you posted

https://www.rx7club.com/3rd-generati...tions-1128664/

That one was a 57366, a different part number, i think it's for the earlier model that use the R12 system. The first link (discountacparts) in that thread that Kensin had didn't work for me.
https://cimg0.ibsrv.net/gimg/www.rx7...fce26b5daa.jpg
This was the same one I received twice from 2 different eBay sellers (probably from the same warehouse). Discountacparts is also the same seller as bestautoparts from eBay (when I checked out with PayPal, same payment address). The R12 compressor did not fit in my car...

Gotcha, my bad. I didn't notice the 1 number off. Why wouldn't it fit? Are the ports different? Or bolts up different?

I can't answer that because my mechanic was doing the work (sorry I'm not good with my hands). I think he told me over the phone that the ports are different size.

If you look at Dale's pictures above that compressor is from a newer JDM R134 car.

The ports on that one are different from a USDM R12 compressor also. You can show those pictures to a mechanic, and see if he can compare to your R134 compressor. I was able to find 2 of these in the US, one from Dale and 1 from an importer, both within my state. If it would work i'm sure you can track one down.

Another option would be to use the readily available compressors and have the hose ends swapped at the compressor side.

I just purchased a Series 6/7 JDM AC compressor yesterday from another forum member. I will update this thread when I receive it. If it does fit, I will do a reverse search on Miata compressors on ebay to see if the part numbers are the same...

I have the 4 seasons compressor and it's working great with R12 refrigerant. Where was your leak?

I honestly don't see how it matters what year compressor you use - they should all have the same form factor. If it's from/for a R12 car you just need to dump/pump out the mineral oil and put the appropriate amount of PAG oil in there. In that case I would use BG frigiquiet R134 pag as it even blends with residual mineral oil. If the comp is from/for a 134 car and you're using it on an R12 system dump it out and use mineral or ester.

Bottom line just make sure the correct oil and amount is in the compressor & system. These guys and gals offer one pre-loaded with PAG oil and it includes switch&clutch: https://www.ackits.com/comp-tv14c-wsw-clutch-3038 so it should be good to go for a 134 car.

Edit: why didn't the R12 compressor fit in your car?

You used the 57367 part number? The problem I have right now is the fitment (might be different size port) not the refrigerant... Also, if I'm correct, the Mana and Denso compressors should be the exact same fitment. Are the R12 and R134a compressors different in terms of port size?

Ok, I may have been wrong about compatibility then. I used 57366.

That's a good question on port size. I have an original R12 compressor I can measure port inside diameters on to compare to your S6/S7 compressor and the 1995 compressors.

I am a bit confused by the Denso nomenclature. I've seen these compressors referred to as TV14 and TV12 model numbers depending on year. I can't find dimensions or a drawing anywhere, but they list o-ring sizes below and they don't match up for 57366 TV14 and 57367 TV12 compressors.

From the 4 seasons part info documented on rockauto:

57366 Compressor (for 1993 car)
Refrigerant TypeR-134A
Pulley Groove QuantityNR
Clutch IncludedNo
Compressor TypeTV14
Mounting TypeTangent Mount
TypeNippondenso
O-Ring B Number/Desc[24610] / Green O-Ring, I.D. IN 0.546875, O.D. IN 0.64
O-Ring B Quantity1
O-Ring A Quantity1
DescriptionCompressors - Reman
O-Ring A Number/Desc[24608] / Green O-Ring, I.D. IN 0.426, O.D. IN 0.531
Switch / Sensor DescSpeed Sensor
StyleVane
Oil TypePAG 100
New or RemanRemanufactured
Suc Prt Typ NoteR12
Suction Port TypePad Mount
Printed Foot NoteMay Require use of OE Manifold

57367 Compressor (for 1995 car)
Refrigerant TypeR-134A
Pulley Groove QuantityNR
Clutch IncludedNo
Compressor TypeTV12
Mounting TypeTangent Mount
Oil TypePAG 100
StyleVane
O-Ring B Quantity1
O-Ring B Number/Desc[24661] / Green O-Ring, I.D. IN 0.4375, O.D. IN 0.5775
O-Ring A Number/Desc[24681] / Green O-Ring, I.D. IN 0.53125, O.D. IN 0.6895
New or RemanRemanufactured
Printed Foot NoteMay Require use of OE Manifold
O-Ring A Quantity1
Suction Port TypePad Mount
Suc Prt Typ NoteR134a
TypeNippondenso
DescriptionCompressors - Reman

So it looks like the compressor type doesn't matter. Here is the Series 6/7 compressor that was just installed on my car (95 Mana):
https://cimg9.ibsrv.net/gimg/www.rx7...3bcd42778d.jpg
Sorry it's pretty dirty and I didn't get a chance to measure the ports. But since this fits, it means that the Four Seasons 57367 (TV12) port has the same size as this one (TV14C), I will take those measurements when I get it back. Part number 442500-4572 which is one number off from Dale's (4571).

That rear casting looks different than my compressor. The rear of mine looks like the TV14C you posted above. See album linked below.

I measured the port IDs on my R12 TV14 compressor which I believe is the original. They matched up pretty well with the o-ring OD's listed above. Ports were about .02 to .03 undersized compared to o-ring OD so that makes sense for making a seal. What is annoying is there are like 3 steps in my ports where you can measure ID. I measured the diameters marked in black in this album: https://photos.app.goo.gl/TnRHossSLSwzbKTs7

57366 R12 Compressor (for 1993 car)
Compressor Type TV14
O-Ring B Number/Desc[24610] / Green O-Ring, I.D. IN 0.546875, O.D. IN 0.64
- Measured inside diameter .616"
O-Ring A Number/Desc[24608] / Green O-Ring, I.D. IN 0.426, O.D. IN 0.531
- Measured inside diameter .500"

I don't have a micrometer, so these are the best half-assed measurements I can get...
https://cimg8.ibsrv.net/gimg/www.rx7...ac04c168af.jpg
https://cimg9.ibsrv.net/gimg/www.rx7...0db8117a21.jpg
Looks like 5/8 inch on the first hole and the second hole is 3/4 inch...and I spilled antifreeze on my pants afterwards...

Eh, hard to tell actual sealing surface diameters without caliper measurement.

However, I think it's safe to assume there exists at least two versions of the TV14C compressors with different port sizes that may correspond to the refrigerant type they were intended for.

I agree, lesson learned after buying 5 compressors...

My AC compressor [1993 MANA R12 system] has a leak. UV dye is apparent on my compressor clutch and on the tail housing of the compressor. I've spent a few hours attempting to source a new compressor or explore my options. Most places are out of stock of reman compressors and new are not available. Mazda is effectively useless in sourcing any gaskets or repair materials as well. In my searching, particularly for TV14C on google, I've discovered that a compressor seal kit exists. Seal kit is Santech MT2064. I also ordered Santech MT2163 [shaft seal], MT0985 [clutch bearing], and MT2027 [snap ring kit for the clutch and coil]. I'll take plenty of pictures and document a nice little How-To for rebuilding our compressors. Wish me luck my dudes.

Matt

^Nice, I have considered doing the same. I'm sure the shaft seal at minimum is DONE at 100,000 miles. The seals between the sections are metal gaskets and look to be pretty hardy. There's an O-ring seal on a top part of the compressor, don't know what it's called.

I think I saw online pictures of a rebuild kit that looked right compared to the gaskets and what not I was seeing. I have a feeling the compressor isn't too exotic, it's probably similar to other ND compressors, but the fact that it's old is a strike against finding parts.

Dale