(05-29-2021, 06:13 AM)1969_Mach1 Wrote: I've only done one conversion and the kit with the new charging valves and oil had instructions on what percentage of the original R12 charge to use.
If it were my car, I'd first try to find some R12 maybe on EBay. The R134A molecules are smaller than the R12 molecules and tend to leak at connections and some merely through the old hose material in R12 systems. R134A systems use more elaborate multiple O-ring connections and different types of hose. Also, R134A operates at much higher pressures than R12. So, old R12 compressors tend not to last very long.
Ah, when i said original system I meant "generally" it was changed to R134 around 20 years ago and had a new York compressor in 2011.
I had it charged yesterday with 20oz as the High side valve is seized and didnt want to wreck anything, I was more interested in seeing if it worked at all and it does, I have cold ( reasonably) air.
my plan is to change the valves, drier and expansion valve next year.
I've since found a receipt from 2011 and it had 28oz put in then so might try nearer that next year.
Of course things never run smoothly with old cars, by the time I got home I'd developed a "sticky / duff" tappet i think (it was a warm day, for us anyway and even though the inaccurate gauge stayed low I know it got hot under the hood)) making a bit of noise
Again looking at a bill from 2003 ( only 2,000 mls ago) there were lifter issues ( trans oil put in for a bit which obviously cured it) so I now have to plan to change them all I think, another steep learning curve but i did plan on taking the manifold off and cleaning it anyway so I might kill 2 birds soon.
Any tips about changing lifters and setting the clearances will be gratefully received