[More] actually, leaving no room for the gas to expand. That expansion is the energy release that causes the cooling effect.
Then we use all that horsepower to compress and turn it back into a liquid / rinse / repeat
Anyone purchase/install the LMR R-134a conversion kit?
- Thread starter Ricomondo
- Start date
[More] actually, leaving no room for the gas to expand. That expansion is the energy release that causes the cooling effect.
Then we use all that horsepower to compress and turn it back into a liquid / rinse / repeat
I saw pressure approaching 400 psi on the high while I lowered the low pressure switch to less than 20, because it just can't keep up well in the heat. If I burn out the compressor, I guess I'll just have to learn my lesson.
Looks great! - Thanks for the response. Any issues getting the condenser to fit? I've read it's thinner than OEM and doesn't fit in the stock brackets very well?
Looks great! - Thanks for the response. Any issues getting the condenser to fit? I've read it's thinner than OEM and doesn't fit in the stock brackets very well?I’m did a customers car with the whole kit we added the ac back on to . Worked great
Pulled a vac with it and let it sit for a good bit . Charged it up and it was great no issues on temp.
I did a Spectra Premium condenser. It fit fine, no issues.
The new condensers are thinner than the older ones, which affects refrigerant capacity slightly. So when you add the required 8-10oz of oil, you'll probably expect to add 38-40 oz of refrigerant vs the original fill of 42 oz.
The 80% charge idea that is commonly thrown around has nothing to do with the process of going from R12 to R134 and more to do with the fact that folks doing this usually overfill on oil when doing retrofits. They add the required R134a oil, but never really get all the old oil out. Oil doesn't compress. So if you overfill on oil, install the new (smaller) condenser you cannot add the full 42 oz or you will pop off the high pressure relief. Hence the 80% rule.
Brand new system? Have a rough idea of how much oil you added? Then really you are only reducing a few oz for the smaller condenser. Charge to 36-38 or so and watch pressures as you creep up a bit to 36-38. Should be using manifold guages to charge as you need to keep an eye on high side.
One of these days I need to put together a Fox-specific write-up on AC. There's some good ones but they miss out on some details.
The new condensers are thinner than the older ones, which affects refrigerant capacity slightly. So when you add the required 8-10oz of oil, you'll probably expect to add 38-40 oz of refrigerant vs the original fill of 42 oz.
The 80% charge idea that is commonly thrown around has nothing to do with the process of going from R12 to R134 and more to do with the fact that folks doing this usually overfill on oil when doing retrofits. They add the required R134a oil, but never really get all the old oil out. Oil doesn't compress. So if you overfill on oil, install the new (smaller) condenser you cannot add the full 42 oz or you will pop off the high pressure relief. Hence the 80% rule.
Brand new system? Have a rough idea of how much oil you added? Then really you are only reducing a few oz for the smaller condenser. Charge to 36-38 or so and watch pressures as you creep up a bit to 36-38. Should be using manifold guages to charge as you need to keep an eye on high side.
One of these days I need to put together a Fox-specific write-up on AC. There's some good ones but they miss out on some details.
It actually does. It has to do with the expansion rate and ratio of each of the coolants. Filling with R134 beyond the 80% mark in/on an R12 system increases the chances of extreme pressures in the compressor and leading up to the evaporator. That 20% is the extra room needed to allow the R134 to turn into gas before being pushed down the line since the R134 takes [longer] to do this than R12.
If the fluid fails to expand while more in coming in behind it to fill space, then the high pressures result and things start happening that are bad.
I went through all this many years ago until I got with a local guy that explained it all very well, demonstrated it on his gauges, and helped me get it sorted out on the 86.
The orifice affects this process too and shares similar symptoms when it's not working right.
Dontknowchit
Active Member
- Jul 31, 2017
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This is ony list to add a system back in but outside my wheelhouse. Should I buy the kit, install and then take it to a shop or just bring it with the parts in the back?
