Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Friendly format provided to inquire about automotive a/c systems.
Archived Forum

Moderators: bohica2xo, Tim, JohnHere

90efAACIF
Posts: 19
Read the full article
Joined: Thu Feb 16, 2023 7:44 pm

Re: Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Post by 90efAACIF »

Quick update - The compressor is back in the car as planned with the factory supplied shipping pads that seal in the SP-10 oil that Sanden put in during manufacture. I'm relieved that the pulleys line up well with no belt squealing. That wasn't a certainty since the mounting bracket, some of the idler pulley parts and the crankshaft pulley for the next gen civic are different and my calculations and measurements left some axial uncertainty. All the hard lines and hoses are removed along with the condenser and drier.

It will be a few weeks before I get back to this project but I will post updates.

Thank you tbirdtbird and JohnHere for your help.
User avatar
JohnHere
Preferred Member
Posts: 1197
Joined: Sun May 13, 2018 10:20 am
Location: South Carolina Upstate - USA

Re: Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Post by JohnHere »

While they're in storage for a few weeks and waiting to be installed, ensure that all the components are tightly capped—especially the R/D—to prevent dirt, insects, air, and moisture from entering.
Member – MACS (Mobile Air Climate Systems Association)

Thankful for the responses you have received? Please consider making a monetary donation to this Forum.
ice-n-tropics
Posts: 157
Joined: Sat Apr 23, 2016 3:40 pm

Re: Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Post by ice-n-tropics »

FYI, 4993 is recommended for CW applications. Civic is CCW. Wobble/swash plate compressors shift anti rotation gear full engagement verses piston TDC to advanced timing to reduce noisy backlash in CW rotation only. The OEM scroll is CCW only. The piston substitute for OEM scroll will be noisier but durability is fair. Sanden Singipore has one CCW piston model. You might review if your old scroll is OK.
hotrodac
90efAACIF
Posts: 19
Joined: Thu Feb 16, 2023 7:44 pm

Re: Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Post by 90efAACIF »

A couple of weeks turned into a month (visitors, taxes and doctor) but I'm back.
Post by ice-n-tropics » Mon Mar 20, 2023 1:40 pm
FYI, 4993 is recommended for CW applications. Civic is CCW. Wobble/swash plate compressors shift anti rotation gear full engagement verses piston TDC to advanced timing to reduce noisy backlash in CW rotation only. The OEM scroll is CCW only. The piston substitute for OEM scroll will be noisier but durability is fair. Sanden Singipore has one CCW piston model. You might review if your old scroll is OK.
hotrodac
Ice-n-tropics apparently saw the same incorrect info that I saw (on Sanden's website of all places). The 4993 is CCW only. All pics of the 4993 label (USA and Japan mfg) show CCW as does the spec drawing. Go to: sanden.com home page and enter 4993 takes you to: sanden.com/product.php shown below.
4993_php.jpg
4993_php.jpg (232.08 KiB) Viewed 1618 times
my label:
LabelSm.jpg
LabelSm.jpg (240.5 KiB) Viewed 1618 times
I'll post a few new questions in the next day or so.
ice-n-tropics
Posts: 157
Joined: Sat Apr 23, 2016 3:40 pm

Re: Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Post by ice-n-tropics »

ice-n-tropics wrote: Mon Mar 20, 2023 10:40 am FYI, 4993 is recommended for CW applications. Civic is CCW. The OEM scroll is CCW only. You might review if your old scroll is OK.
hotrodac
ice-n-tropics
Posts: 157
Joined: Sat Apr 23, 2016 3:40 pm

Re: Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Post by ice-n-tropics »

Jim,
Sorry we had to deal with confusing Sanden's screwed up spec for wrong rotation . Hopefully others will benefit. I will cross check all available info, as you did, in the future.
90efAACIF
Posts: 19
Joined: Thu Feb 16, 2023 7:44 pm

Re: Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Post by 90efAACIF »

Quick Summary of where we are in the project: 90 Civic being adapted to use newly manufactured Sanden 4993 used in next gen Civic.

The system was previously converted to R143a by an honest but not expert local mechanic. The original TR-70 compressor appeared to be working, and the conversion only included a new receiver / drier and PAO 68 (Polyalphaolefin) - non hygroscopic, compatible with R143a and R12 and mineral oil. At the time I thought that was probably the best choice over the correct PAG oil since the mechanic couldn’t get the old mineral oil completely out without removing the compressor. About a year later a refrigerant leak occurred. I took it back to the same mechanic who found a leak in the condenser and replace it with a parallel flow design. That repair worked for less than a year with the original TR-70 compressor which then supposedly failed with a crack on its rear cover under its heat shield, dumping the charge and U/V dye. I doubt that diagnosis at this point since my later inspection after removing the compressor and heat shield shows no crack. The compressor was not locked up.

I suspect the more likely failure mechanism to have been over-pressure that blew the safety valve under the heat shield. Possible support for that:

1) Failure occurred on one of the hottest days of last summer during an extended drive. I heard the rapid loss of refrigerant and the system stopped working immediately.

2) The mechanic recharged the system, said it wasn’t leaking and took it for a successful test drive.
3) Upon picking up the car several hours later, there was no A/C and no pressure in system. That’s when the mechanic gave his diagnosis noting the U/V dye sprayed from the back of the compressor and recommended replacing the compressor.

Possible mechanisms for the over-pressure:

1) Blockage on the high side – condenser or TXV. I suspect insufficient flushing leaving wear particles and the PAO / mineral oil concoction may have led to blockage in the very small tubes of the parallel flow condenser.
2) Failure of the over-pressure switch in the liquid line to open, thus blowing the safety valve. The valve body is very corroded.
3) Missing foam blocks that seal the space between the edges of the condenser and radiator, lowering air flow through the condenser.

Initial attempts to find a new / not rebuilt TR-70 failed and led to much research over a few months. I found and studied the 4993 replacement threads listed in my first post. The 4993 ships with the correct amount (130cc) of double end capped oil (SP-10) for the complete system. I have already installed the 4993 with the factory supplied shipping pads that seal in the SP-10 oil to keep it uncontaminated until the system can be finished.
90efAACIF
Posts: 19
Joined: Thu Feb 16, 2023 7:44 pm

Re: Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Post by 90efAACIF »

More to come soon. Uploading images isn't cooperating well. Will try again later this evening.
Remaining topics will follow, one per post.
Uploading images is apparently limited to 3 per post. I'll try combining some of them using a photo editor.
90efAACIF
Posts: 19
Joined: Thu Feb 16, 2023 7:44 pm

Re: Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Post by 90efAACIF »

remaining topics for discussion:

1) Binary HPCO/LPCO pressure switch replacement:

Besides the facts that the original binary switch is 32 years old and the crimped portion of the case is badly corroded, I think it makes sense to change to a higher pressure cut-off for R-134a as spec’d for the ‘94+ Civic. No one on the Civic forums has suggested this, but it should have a big advantage in very high ambient temps / humidity as we have in Florida.

From the ‘96 manual for R-134a: ------------------------------------------------- From the ‘90 manual for R-12:
p1a.jpg
p1a.jpg (239.34 KiB) Viewed 1526 times
Replacement from the UAC catalog for '96 ------------------------------------- Replacement from the UAC catalog for '90

Since the thread size is different I looked for one with similar pressure specs to the SW 10000C that will fit and found this:
p1b.jpg
p1b.jpg (248.45 KiB) Viewed 1526 times
This switch is sold under many brands (omega, santech, GPD and more) but all I’ve seen online have identical labeling on the plastic case. This will need a new connector which I have also found.

Next topic tomorrow...
90efAACIF
Posts: 19
Joined: Thu Feb 16, 2023 7:44 pm

Re: Plans for 90 civic A/C rebuild with newer gen Sanden compressor - remaining questions

Post by 90efAACIF »

2) O-ring sizing and quality:

I am concluding that proper o-ring selection is easier said than done. I might be better off leaving the o-ring selection to the mechanic who finishes the evacuation, leak testing, and charging. At least, if there is a leak, they cannot blame me for having chosen poorly.

At first I found HBNR O-ring kits such as this to be ubiquitous online and in local auto parts stores:
p2a.jpg
p2a.jpg (245.01 KiB) Viewed 1509 times
Reading amazon reviews showed most people thought they were fine but a significant number reported quality issues such as:
molding flash, bad sizing, easily cracked, early failure, shrinkage, deformed after short time in use, casting bleed-through, defects or tears, feathering of excess material at the seams of the smaller sizes, casting defects and gashes, warped not perfectly round

I followed the final comment suggestion:
I strongly advise anyone who needs o-rings to work and last to download the "Parker O-ring Handbook, ORD 5700", easily googled 9MB pdf.
Having done that and perusing this 292 page compendium I have following takeaways:

There is more info than can be absorbed in the time that most people have available.
If you are interested in only auto a/c systems there are a few things to note. Damage during installation and stretch due to sizing error.

From Parker's Handbook:

p2b.jpg
p2b.jpg (238.8 KiB) Viewed 1509 times
The topic of O-ring stretch suggests that very small amounts of stretch (“more than 2 or 3 %”) needs to be taken into account for a good seal. That implies the replacement o-ring was accurately sized, which might be a tall order.

In the case of the hard lines in my 90 civic, even though the threads appear to be SAE standard sizes, the tubing is metric. The fitting designs look like a male insert design, but I don’t know if they follow any current (or past) standards. Looking in the Parker HPD_4400 Catalog confuses me further, since even for the same dash size (-6, -8, -10 etc) there are different o-rings designed for different fittings (SAE, flange, and their proprietary “seal lock”).

So, are all SAE o-rings that are dash sized the same for male insert o-ring, male o-ring, and female o-ring fittings? I saw some pictures that might suggest otherwise, but nothing in print.

There are kits referred to as Rapid Seal by UAC and Santech for a given vehicle. That my be a solution for the hard lines I’m reusing. Any opinions on the quality of those kits?

I am having custom hoses made that will have standard SAE fittings so o-rings for those should be only a mater of finding a good brand – suggestions?


Finally the compressor manifold adapters I found on AliExpress are shown below. Note the purple o-rings included which I am inclined to replace with known quality. I also don’t know if the included o-rings would give the proper compression for a good seal. I used to have access to a good caliper before I retired. Time to get one for myself!
p2csm.jpg
p2csm.jpg (195.47 KiB) Viewed 1509 times
Locked