First Time AC Charging

[Mark]

Does anyone have a good wtrite up on how to cahrge the AC system in the SPF GT40 the first time? have the gauges and pump.

Thanx
Mark

 

[Seymour Snerd]

Here's what amounts to a generic cheat sheat: http://www.vintageair.com/DownloadsSection/Documents/Initial Charging Instructions.pdf

Notice the refrigerant amount is specific to their product.

And here's a more detailed document, although again likely has some specifics to their product.

http://www.vintageair.com/DownloadsSection/MiscDocuments/ACBASICS(92806)-Inet.pdf

 

[Dalton Veitch]

I note they talk about evacuating the refrigerant system for 30 - 60 minutes. The typical GT40 system with condenser in front of the radiator has a lot of refrigerant piping and/or tubing, so needs longer than this. After leak testing, when you are satisfied with the integrity of your piping system and all its joints, pump down to a vacuum and maintain this for at least three hours. This low pressure boils off the moisture in the refrigerant piping before (of course) you add the refrigerant. To get completely rid of all the moisture in such an extenaive system from mid-engine compressor to front condenser and cockpit evaporator/fan-coil, you need to maintain the pumped down pressure for several hours. Otherwise the moisture contamination reduces the performance of the refrigerant. Just my 2c worth.

 

[Roy]

Dalton is absolutely right, the longer you can leave the system under vacuum the better. You want to make sure you have removed all moisture from the system. If you have had any hose or component of the A/C system open to the atmosphere, for any period of time, you need to vac it down for at least three hours or longer if possible.

 

[DaveM]

Dalton is right. I vacumed sysyem for 3 hours, made sure no leaks before filling. Used 36 oz. r134 and 2 oz. of PAG oil 100 w. There were a couple of o rings I had to replace the first time I vacumed. They were on the central pipe at the front and rear. Use dye to identify leaks.

 

[Seymour Snerd]

...2 oz. of PAG oil 100 w.....

What was your rationale for adding the PAG oil? Presumably the compressor already has a nominal load of oil, so is this system seen as being large enough to to require the additional oil?

 

[DaveM]

I consulted with Roush engines (my engine supplier). They said the Sanden compressor comes with 3.3 oz of oil. Depending on the size of the car they recommended adding 1.5-3 oz more.

 

[Seymour Snerd]

I consulted with Roush engines (my engine supplier). They said the Sanden compressor comes with 3.3 oz of oil. Depending on the size of the car they recommended adding 1.5-3 oz more.

Thanks for the tip!

 

[Steve Wood (PANAVIA)]

If you have access to the machine that is a great thing! - we like to leave the system under vacuum overnight and wiggle lines and connectors to make sure everything is sealed and there will be no leakage due to a loose line. -

The amount of oil and refrigerant is something the shops relay on stated specs for, but this is variable to certain degree. --

too much oil and refrigerant can damage the systems, so be careful !!!

 

[Seymour Snerd]

The amount of oil and refrigerant is something the shops relay on stated specs for...

For an SPF GT40, as far as I know, there are no "stated specs", hence the original question.