AC COMPRESSOR COMPATABILITY PLEASE

[TANTO]

Refurbishing the AC system on my 92. Staying with R12. I see folks recommending Integra and Legend units to save money or get a bit more capacity. I jumped the gun and purchased a legend unit and see it is not the right bolt pattern and will return it. So i need to go to school on my options as I also have a 3.2 swap in the works and hope to do this swap without touching the AC system. Any comments greatly appreciated!

 

[drew]

The base unit should all be the same....the displacement is different

What unit did they send you?

 

[Honcho]

Refurbishing the AC system on my 92. Staying with R12. I see folks recommending Integra and Legend units to save money or get a bit more capacity. I jumped the gun and purchased a legend unit and see it is not the right bolt pattern and will return it. So i need to go to school on my options as I also have a 3.2 swap in the works and hope to do this swap without touching the AC system. Any comments greatly appreciated!

As Drew noted, the base unit 10PA15C is identical (might be a 17C on the Legend). and the mounting holes should line up with the NSX mounting bracket. The differences are the flange plate for the A/C lines and possibly the pulley. Normally, you would swap those pieces over from your old compressor.

Another route you could go is to just rebuild your existing compressor. They sell kits for that and it's not too difficult.

 

[TANTO]

It's a larger Denso size 20 part # 471-1181(partsgeek #) and as stated the pulley is not correct. I'm liking the sound of that rebuild kit all of sudden, but i'm now trying to get a handle on the 3.0/3.2 mountings. I'm seeing there are different comp bracket part no's and now wondering if the block mounting holes are different? In addition Joe G says the exp valves are different from r12 to 134 so i'll apparently have to source an R12 valve(?) as i think my new evap is likely set up for 134.

 

[Honcho]

It's a larger Denso size 20 part # 471-1181(partsgeek #) and as stated the pulley is not correct. I'm liking the sound of that rebuild kit all of sudden, but i'm now trying to get a handle on the 3.0/3.2 mountings. I'm seeing there are different comp bracket part no's and now wondering if the block mounting holes are different? In addition Joe G says the exp valves are different from r12 to 134 so i'll apparently have to source an R12 valve(?) as i think my new evap is likely set up for 134.

The block mounting holes are the same. The mounting holes on the bracket are also the same. The difference between the 3.0 and 3.2 is that the bracket on the 3.2 holds the compressor further away from the engine block to accommodate the headers. This matters because if you use a 3.0 pulley offset on a 3.2 bracket, it won't line up with the crank pulley. Kaz has a really good discussion here:

A/C Compressor replace with a 94 or newer?

The refrigerant is pretty much a non-issue. Yes, the seals are different because the R-134a molecule is much smaller, but existing oil impregnated o-rings seem to have no problem. AFAIK there is no upgraded vanes to compensate for the higher pressures that R-134a puts out. So for all intents...

www.nsxprime.com

Honestly rather than messing around with pulley and bracket combos, I'd just rebuild it. The kits aren't expensive and there are youtube videos on how to do it like this one:

I think the shaft seal protector tool is like $10 on Amazon. Make sure you use the correct oil for R12.

 

[drew]

You can put R12 in a system designed for a R134 system no problem with either mineral oil or ester. You are not supposed to blend refrigerants.*

Yes, you may have to swap pulleys. You may have to swap manifolds. This is all reasonable retrofitting.

The bracket for a 3.2 is different...not sure it matters. The a/c compressor should be the same as prior years too.

Source: MVAC certified.

*There may be individuals on this site that may have done exactly this, especially when they were young and poor.