R12 -> R134a 1989 Porsche Kit Questions

[HC3]

Hello,
I'm new to this forum. Car: 1989 Porsche 3.2L - all components are new or reman. except for the rear lid condenser which was professionally flushed.
Background - I purchased a complete kit (compressor ( Denso filled with ND-OIL 6 mineral oil), hoses (with high/low switch), evaporator, additional condensers, R134a manifold fittings, sticker, etc.) The kit contained BVA Auto 100 Polyolester Compressor Oil. At this point all the new parts are installed except for a replacement drier. The original drier had some crud at the top fitting so I asked for a replacement clean one coming in the mail in a few days.

Before I get past a point of no return I want to confirm all is good relating to draining the mineral oil out and filling with the Auto 100.

Questions:
1 - Am I on right track - Drain oil from the reman. Denso compressor and fill (5.5 OZ) with Auto 100 from BVA? BVA recommended doing this two times to remove as much mineral oil as possible. Is there a better oil for my situation? Pros/Cons?

2. The recommended evacuation and charge procedure is as follows:

I'll start with the evacuation procedure....and see what response I get then add the recommended charging process for comment.

1 - new oil in the vacuum pump, use a heater blanket on the R134a container
2 - use electronic vacuum gauge (I think these are called "micron" gauges)
3 - evacuation and charge at 80F ambient or higher
4 - vacuum for 1/2 hour, watch for 1/2 hour to see if any rise in pressure (fix any leaks found)
5 - Inject nitrogen or refrigerant as a gas until pressure is 10 psig, let sit for 20 minutes
6 - remove/recover refrigerant and repeat 4, 5, 6
7 - pull vacuum for 2 hours
8 - close service gauge set and turn off vacuum pump
9 - wait 15 minutes and check for any rise in pressure, find and fix any leaks.

Thanks for any advise or comments.

-Henry

[bohica2xo]

BVA100 is good oil for 134a systems.

Flushing the compressor only takes a couple of ounces, but yes I always do it twice when switching oil types. Drain as much of the mineral oil as you can first. Compressor flushing procedure:

http://www.autoacforum.com/messageview. ... adid=12050

The evacuation procedure seems a little extreme.

YES to the micron gauge.

Get the system closed up with the correct oil charge. Pull a 1,000 micron vacuum. Close the valves & shut the pump down. Go have a cup of coffee or something. The vacuum will rise no matter what at this point. Give it a half hour.

Now start the pump & pull down to 400 - 600 microns. Pump for 1o minutes or so & close the valves again. Shut the pump off & wait to see if the vacuum holds. How long? Well, I usually wait an hour. In a busy shop some guys push it to 20 minutes.

If it is vacuum tight? Charge it. We have a process for that too, but I will wait for what you put up.

[HC3]

Thank you very much for the reply and info. Your evacuation approach seems logical, I should be able incorporate into the suggested process. I'll post the suggested charge process later today.

I'm having difficulty finding a place that has or uses a micron gauge. One place didn't know what it was. I even went to a place listed on MACS and they said they don't use one. I have a few more places to go - I'll even buy one for them if needed I guess, I shouldn't have to.

Today I'm buttoning up a few more items - maybe I will install new O-rings using Super Lube in places where I didn't feel good about how it went together.
The O-rings are supposed to compress a bit and then slide into the fitting - they are not supposed to be squished by the tall ridge on the fitting, right? The O-ring does the work not the nut. O-rings should compress e.g. 20-35% diameter of cross section - right? The nut should be tight enough to hold the fitting from moving around, that's all it needs to do. Sorry to be a bit OCD on this, I don't want a leak if I can easily avoid it.

[bohica2xo]

If you are not doing the work yourself, you will get whatever the shop feels like doing.

I don't see any tech jumping through the repeated evacuations your plan included. You will be lucky to get a single 15 minute evac & charge at most shops.

Micron gauges are around 150 bucks. Vac pumps can be rented.

Generally we recommend Nylog to snot up O rings & fittings. It is compatible with the system, and available from the site sponsor.

"O" rings seat in grooves. The shoulder that the nut seats on only holds the hose in place.

If you are installing additional condensers, is there a charge weight recommendation from the vendor?

.

[HC3]

I read about Nylog - I'll get some.
I got the car back on the road today.
I'm looking for a place to by more BVA 100 and a graduated cylinder.

Here is the charge procedure provided...

1 - use virgin R134a from a large tank not the small cans
2 - refrigerant filled by weight using a scale
3 - record refrigerant added/etc.
4 - use a good vent temp digital gauge
5 - starting charge 36 OZ weight (in the engine compartment the 1989 sticker for R12 says 47.6 OZ, Bentley Manual says 47 OZ)
6 - Initial charge - can be on high side with engine off
7 - Purge air from service equip.
8 - input initial charge 36 OZ, I guess on the high side
9 - start car and idle for 5 mins, AC on full, evap. fan on 1/2 speed
10 - bring engine up to 2000 rpm for 1-2 mins
11 - bring engine down to idle for 1-2 mins
12 - check high and low pressures per chart for the ambient temp. - if these are fine then stop your done.

If high side is too high - there is a missing sentence it seems....and doesn't say what to do, I assume it means something must have been wrong with the fans/valve/etc.
If vent temps are low and high side is low then add 2 OZ - repeat idle, 2000 rpm, idle and take readings

I half starting to think I could do this myself with the funds I'm going to pay for someone to not do all this. What all do I need? I have time so I don't think I need a fast pump just one what will eventually pull the vacuum needed. Does ACKits have all I need in a kit?

Lets see:
pump
gauges
micron gauge
R134a tank
vent temp. gauge
? what else

Thanks much for your help. What should I expect a shop to charge for all this? I could drive to Las Vegas or Scottsdale, then it would get done correctly.

-Henry

[Dougflas]

If you use a micron gauge, you will probably run into the problem that the micron gauge has 1/4 inch sae flare fittings and you will need an adaptor to get to acme fittings. They are available.

[Cusser]

Wow - you have the resources to keep a 1989 Porsche on the road.

If you're in the USA, why not keep it R-12??? Don't tell me cost of R-12 is the reason !

[HC3]

Re. Nylog....
For R134a and BVA 100 do I use Nylog Blue or Red?
Thanks.

[HC3]

A more inclusive list of equipment/materials for a DIY vacuum and charge:
What am I leaving out? What do I not need? Thanks.

- vacuum pump
- vacuum pump oil
- virgin R143a supply tank
- gauge set with hoses (what brand gauges?, I assume some brands are not considered good enough)
- micron gauge
- micron gauge adapter
- scale to weigh large canister
- dye injection system?
- light to see dye
- electronic leak detector
- recovery tank/system?
- extra O-rings
- Nylog
- extra drier

[Tim]

Re. Nylog....
For R134a and BVA 100 do I use Nylog Blue or Red?
Thanks.

Does not really matter. Use what Nylog you have.