Using different size orifice tubes

[dragbaron]

I've got the A/C working in my '71 Plymouth Scamp that has a 2000 5.9 magnum swap. I'm using the '71 condenser and evap core with a '94 Ram compressor, accumulator and orifice tube. I had lines built to connect it all.

Pulled vacuum for 2 hours, then let it sit another hour. No leaks, so I charged it. Ram/Dakota calls for 32 ounces, but I'm not technically 100% Ram/Dakota anymore. I got 24 ounces in it and my low side pressure is too high.

One possible cause people have said is that it may be leaking past the orifice tube. I had a thought that since these orifice tubes are designed for a specific system setup, that maybe the purple Dodge orifice tube is too big for this system and allowing too much flow through it.

If so, can a smaller orifice tube from, say a Ford, be installed to slow down the flow and lower my pressure on the low side?

[Dougflas]

Ford Color

Blue .067

Red .062

Orange .057

Green .052

Brown .047

GM Color

white, Black/white .072

Some tubes have only a single o ring, most have 2 o rings

[mk378]

The old-style condenser isn't helping you any. What is the high side doing? A lot of conversions end up undercharged to mask poor condenser performance.

[dragbaron]

The high side got up to around 200, but I kept a water hose near to spray the condensor and would keep it in the 150 range. Keeping the high side lower seemed to help the low side pressure to come down as well.

[dragbaron]

I've thought about using the Ford blue .067 since the Chrysler is .072. I just wasn't sure a Ford orifice tube would fit in a Chrysler.

[Dave in Texas]

I converted the R12 system on my '87 DeVille to 134a some years ago. The suggestion made to me about which orfice tube to use for the 134a was Ford blue, instead of the GM white. The AC system has worked fine ever since.