R12 Charging questions

[CyFi6]

No time to type it all out but I'll repeat something I've said before about all sorts of things fan related: more CFM is not necessarily better. Has to do with residence time. Iirc didn't/don't you also have cooling problems?

Been researching this a bit and I still can't figure out how you came to the conclusion that there is not enough residence time for air through the radiator when using the Tundra clutch. There's a few things I don't understand.
-First of all, I can't see how residence time of air through the radiator can affect how much heat is removed. If the metal fins of the radiator are releasing heat at a constant rate, how could an excess amount of air flow hinder heat removal? If cooler air next to the fins makes for faster heat transfer (higher delta t) then how would having a constant supply of cool air slow heat transfer, why would it matter how fast the air is moving?

-Second, with a thicker radiator, such as my Koyo, wouldn't an increase in air volume/speed be desired? By the time the air reaches the back of the radiator, it has already been warmed by the front half, so if you could increase the amount of air flow, it would seem the warm air would be removed quicker and the cool air introduced quicker.

-Third, at what RPM are you suggesting there is not enough residence time when using the Tundra clutch? From 650 crankshaft RPM all the way up to 6500, the air speed and volume changes drastically. You say that the Tundra clutch is a bad idea to use, because of the high amount of airflow..but at what engine RPM? A stock fan clutch will pull a ton more air at 6000RPM than a Tundra clutch will pull at 650.

-Lastly, my understanding was that the only difference between the Tundra clutch and stock was that the Tundra clutch begins engagement at a lower temperature than stock. I was under the understanding that both clutches have the same amount of engagement, but the Tundra engages sooner, am I wrong in saying this?

Keep in mind, I have had absolutely no training in thermodynamics or fluid dynamics so all I am trying to understand here is the basics.

Do toyota reman compressors and brand new denso units come preoiled with mineral or ester? It doesnt.say.and does anyone recommend changing the oil oil out when I get the new one?

Can't say with certainty what the compressor would come with, but it is always a good idea to turn the compressor over and rotate it to drain all the oil out, then fill it with the desired amount of new oil. If you flushed the whole system, you can fill the full oil charge into the compressor inlet after it has been drained.

 

[3p141592654]

Well, I am at odds with JJ on this one. My research and training says residence time is an urban myth. If water stayed in the radiator longer to cool down, it would also stay in the engine longer and get hotter before going to the radiator. It's a closed system after all.

The radiator heat transfer is proportional to the temp difference between the air and the coolant, so the longer the coolant stays in the radiator the cooler it gets, and therefore the heat flow from coolant to air decreases. The worst case would be the coolant flow is so low that before it exits it is at ambient, and some fraction of the core has absolutely no heat transfer (the effective core area decreases). The ideal case is infinite coolant mass flow though the radiator. The radiator would then be at an asymptotically uniform temperature across the full core and the delta-T to the air integrated over the area of the radiator would be at a maximum. Now the delta-T of the coolant would be asymptotic to 0, but since the mass flow rate is infinite, it washes out.

One other thing, the coolant mass flow rate also determines how much heat can be transferred from the engine to the radiator. The higher the flow rate, and the more capacity you have.

In practice, loss of laminar flow (turbulence) and pump cavitation limits the peak flow that can be used. NOT because the water needs to spend more time in the radiator.

Similar arguments can be used for the air flow as well.

 

[JDMMA70]

Can't say with certainty what the compressor would come with, but it is always a good idea to turn the compressor over and rotate it to drain all the oil out, then fill it with the desired amount of new oil. If you flushed the whole system, you can fill the full oil charge into the compressor inlet after it has been drained.

Is it always hard to break the manifold bolts loose on the compressor to drain the oil? I dont want to put it in a vice if i dont have too.

 

[CPT Furious]

For a parallel flow condenser, look here: (#106)

http://www.supramania.com/forums/sh...ion-Chill/page3&highlight=chill+parallel+flow

I called them a few weeks ago and they are still available for about $182. I'll also donate my penny and say the Tundra fan isn't worth it. Sure it pulls air, but I had trouble getting the damn thing to disengage on the highway. Loud as heck. The stock clutch in good working order and the GTE fan with my Al rad do just fine.

 

[CyFi6]

Is it always hard to break the manifold bolts loose on the compressor to drain the oil? I dont want to put it in a vice if i dont have too.

Not sure which bolts you are referring to. You just need to open the ports and turn it upside down, then rotate the shaft to drain the oil. Not sure if yours came with a plate on top or what, but when I got mine (believe it was a reman) it just back a blockoff plate on top, and I had to transfer my top plate from the old compressor to the new one.

 

[JDMMA70]

Not sure which bolts you are referring to. You just need to open the ports and turn it upside down, then rotate the shaft to drain the oil. Not sure if yours came with a plate on top or what, but when I got mine (believe it was a reman) it just back a blockoff plate on top, and I had to transfer my top plate from the old compressor to the new one.

Oh so which port does it come out of suction or discharge and i just rotate the clutch till all the oil comes out.

 

[CyFi6]

Ya it will come out of either ports, just turn it over and rotate the clutch around until the oil stops dripping out.

 

[JDMMA70]

Ya it will come out of either ports, just turn it over and rotate the clutch around until the oil stops dripping out.

Fill the oil in either port?

 

[CyFi6]

Fill it through the suction port as you rotate the clutch. Make sure you are adding the proper amount of oil, if you put too much it is difficult to adjust the amount later, and damaging if you don't put enough.

 

[JDMMA70]

Fill it through the suction port as you rotate the clutch. Make sure you are adding the proper amount of oil, if you put too much it is difficult to adjust the amount later, and damaging if you don't put enough.

ill just go by the TSRM amount. Cant go wrong if you go by the book is what i always say

 

[CyFi6]

Yeah, good idea. You will have to add all the amounts together though if you are starting from a dry system, they don't give you a full system oil quantity.

 

[JDMMA70]

Yeah, good idea. You will have to add all the amounts together though if you are starting from a dry system, they don't give you a full system oil quantity.

So basically to clarify in case other people are a tad confused. My old R12 was already recovered so theres nothing in the system and im assuming thats what you meant by dry. So basically it would go like this.
Add 80 +/- 20cc of compressor oil to the compressor. Then add 20cc of oil to the new Drier/Reciever. Going by what all was replaced? Im assuming the +/- is compensating for the Drier?

 

[CyFi6]

Was the system flushed (evaporator, lines, condenser)? If not, you really don't have a great idea of how much oil remains in the system, it gets distributed unevenly throughout, so you can only estimate based off what the TSRM tells you. If you have flushed the system, you just need to add the amount of oil each component requires, and fill the entire oil charge into the compressor. If you are just replacing single items, you just need to add however much oil the TSRM says for each item you are replacing (can put the total amount in the compressor to make things easier), but again this is not all that accurate as oil can unevenly distribute itself.

 

[JDMMA70]

Was the system flushed (evaporator, lines, condenser)? If not, you really don't have a great idea of how much oil remains in the system, it gets distributed unevenly throughout, so you can only estimate based off what the TSRM tells you. If you have flushed the system, you just need to add the amount of oil each component requires, and fill the entire oil charge into the compressor. If you are just replacing single items, you just need to add however much oil the TSRM says for each item you are replacing (can put the total amount in the compressor to make things easier), but again this is not all that accurate as oil can unevenly distribute itself.

No nothing was flushed. As far as i can tell i would assume it was done recently as in maybe 8 years ago. It has a brand new condensor and the drier was replaced along with the compressor by the previous owner. Right now im in the process of getting a new compressor as stated earlier and the drier. I understand based on what youre saying that we cant actually gauge how much needs to go back in. So maybe just to stay on the safe side ill just add 100cc to the compressor and call it good. 80 for the compressor and 20 for the drier.

As far as the items that were replaced by the previous owner i know it was done at a dealership and judging from how they work they probably didnt check the amount of oil in the compressor before installation which could explain why the compressor had such a short lifespan the clutch started wobbling with the a/c on. As soon as it started i didnt run the a/c (eventually one day i decided to see if it my a/c was still cold the clutch wouldnt engage and thus we are here where we are now) and now its too hot i cant stand it. So im on a mission to be ice cold by september.

 

[fixitman04]

my question on the tundra fan clutch is how does changing the fan clutch effect cfm....it would effect engagement time...not cfm. the fan is what effects cfm...not the clutch. the clutch would only change what temp it engages...and to what extent.

 

[CyFi6]

-Lastly, my understanding was that the only difference between the Tundra clutch and stock was that the Tundra clutch begins engagement at a lower temperature than stock. I was under the understanding that both clutches have the same amount of engagement, but the Tundra engages sooner, am I wrong in saying this?

my question on the tundra fan clutch is how does changing the fan clutch effect cfm....it would effect engagement time...not cfm. the fan is what effects cfm...not the clutch. the clutch would only change what temp it engages...and to what extent.

Something I was wondering as well.

 

[Scot]

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=AC&P=17

The whole A/C section was extremely helpful for me...... The basics are no longer a mystery.... The troubleshooting guide is actully usefull giving what to check 1st, 2nd, 3rd and so on.....

More reference material on R-12 to R-134 conversion.....

http://www.ccar-greenlink.org/documents/Toyota_Retrofit_ac002t98.pdf

 

[jetjock]

^ Thank you. I had mentioned in another thread that retrofit bulletin was out there somewhere but I'd lost track of it. Copy saved.

Cy: Stock runs at 70% while the truck clutch is capable of running to 90%.