Engine Swap A/C thread

[Elbert]

OK... may have asked before...here goes again.
1986 FJ60...out goes the I-6, in goes the 5.7 Vortec. Retained all OEM A/C equipment except compressor. Will run GM compressor and custom hoses....and the rest yota stuff.

Question: What's the best way to control the A/C compressor cycling on and off. (1) use the stock ac amplifer and stock wire that connected to compressor for on / off ? if so how is your setup? (2) use relays and potentially a GM cycling switch on one of the scharader valves to control cycling (custom wiring).

What's worked for you... those that have a GM V-8 in their 60, running GM compressor and toyota A/C parts?

 

[alaska60]

I used my oem compressor and mounted it on the top drivers side. The hoses and connections were long enough to reroute to this position.

 

[Elbert]

Yota OEM compressor long gone....went by-by with I-6 engine. Still worked well until "last call"..

Looking for setups with GM compressor & otherwise Yota OEM A/C components (stock condensor, evap core, revicer dryer...etc). I have the single fan belt setup too.

 

[ntsqd]

I don't even play an A/C tech on tv, but I did get some A/C-Refrigeration training way back in the last epoch when I was in high school.

The A/C system won't care what the source of the pressure is as long as it is within the intended range. If the Toyota system works and can supply the necessary voltage to the GM compressor's clutch that is how I'd set it up. It is how I plan to set mine up.
If the OE supplied voltage/current is too low for whatever odd reason, then I'd use the OE wire to drive a relay that in turn drives the GM clutch.

 

[ferd69]

I'm running GM compressor and toyota A/C parts. Works good. Rover67 is too.
You should be able to use stock hose with an adapter.

 

[Elbert]

NTSQD:...Yeah I'm familiar with A/C to some degree at least on cars... old school.. I left the pay for mechanic world in 1989...if that gives you a clue as to the time frame.. Yeah I thought about have the yota a/c wire trigger a relay which in turn powered the A/C clutch. Issue as I know it...is the yota a/c is driven by an A/C amplifer that gets some type of rpm signal from the OEM yota wiring setup ( I assume soemthing connected to the coil setup)...based on a 6 cylinder.

Ferd69: Yeah I've corresponded with rover a few times on this...planned to get with him by email or pm to run down the details. When you say stock hose I'm assumeing you are talking about the stock GM A/C hose that comes off the compressor? IF so where adapters you are talking about? Got pics? Website? on a 99 vortec 5.7 the GM compressor sits high on the drivers side. I think I still have the GM compressor hose (dual hose)... the yota one left with engine assembly as I recall.

 

[rover67]

Hey Elbert!

Do you have a good tach signal coming from the ECU? Does your current tach work?

If so here's what I did (after having to use an MSD Tach adapter to get a good signal):

I wired the tach output of the ECU (or MSD Tach adapter in my case) to the original coil negative wire.. after you get rid of the ignitor there is only the wire left going to the AC control for the RPM signal. that's what I wired it to.

It cycles on and off like it's supposed to.

as far as the hoses go, I used Ray's Auto Air & Heat - Auto Air Conditioning Parts & Accessories, A/C Hoses & Fittings he made me a set of custom hoses for the 5.3 vortec that I believe are on his site under "custom hoses by application" on his home page. those won't help you, but if you call him and talk to him he'll tell you what hose ends you need and will give you enough info so you can sketch out the hoses like yo uwant them (with high and low fill ports) with the ends like you want them. I ended up sending him my original hoses with a few changes sketched and pictures showing what I wanted and he made up th eperfect set for me.

I am running th eGM compressor with all other stock fj60 parts. it works well.

-Marco

 

[ntsqd]

NTSQD:...Yeah I'm familiar with A/C to some degree at least on cars... old school.. I left the pay for mechanic world in 1989...if that gives you a clue as to the time frame.. Yeah I thought about have the yota a/c wire trigger a relay which in turn powered the A/C clutch. Issue as I know it...is the yota a/c is driven by an A/C amplifer that gets some type of rpm signal from the OEM yota wiring setup ( I assume soemthing connected to the coil setup)...based on a 6 cylinder.

Interesting. I was not aware of what the amplifier did. Thanks for the heads-up!
Why did they do that? To kill the A/C when at idle?

So then it sounds like what Rover67 suggests is spot-on.

That or figure out how to eliminate the need for the RPM input to the control system.

 

[rover67]

I also forgot to add that I wired the original wire that went to the FJ60 compressor clutch to the AC on request for the GM ECU. Thats where i pick up my signal to tell the ECU to engage the GM clutch.

Also, the RPM signal is off (corrected at the tach for me), but the adjustment on the AC Amplifier seems to have enough adjustment so the AC compressor only turns off below 4-500 RPM.

I think they added the low RPM cut out feature to just keep the AC from stalling the truck and to make sure that the compressor is disengaged while cranking originally.

 

[Elbert]

I don't know the real reason behind the A/C amplifer.....and tach signal, but does sound reasonable that it might not let A/C engage if RPM to low, might also have a high rpm limit. I've not read up on it to really see. I'm interested in the cycling control aspect. I noticed the GM compressor was a little $$ last time I checked but summer is on us and cool is worth $$.

I'll look into the wiring of the GM PCM... I don't recall seeing a A/C signal wire but its been some time since I looked. I do know the PCM has some type of A/C on input which I suspect supports high idle or with the stock GM setup maybe even controls the A/C on command. A/C is enabled in the PCM, maybe I can figure out what it will take to get high idle to work...that would be "cool"... I did talk or email the guy recommended on the hoses... but back then I was having to do too many other things to get A/C going too.

Thanks for the info Rover.... I'm trying to get dual batteries setup (bought stainless trays)...and then get winch wired up. Hopefully I can get to 78 series batteries to work / fit.

Appreciate feedback from others too.

 

[djawahir]

Elbert, I'm still in the process of doing my v8 swap and I found some a/c compressor blocks that hook up to the compressor and allow you to run your toyota a/c hoses without having to get custom hoses made up. The blocks can be found at Doc's Blocks Home.

I'm very interested in this thread...

 

[ntsqd]

A trick that a friend of mine did with the Corolla GTS engine that he put in his Samurai was to wire a switched signal with a diode to the PCM's A/C command wire. Turning that switch on told the PCM that the A/C was (but the diode blocked the clutch from working) and it raised the idle accordingly. Worked pretty slick on that little engine because the idle speed came up a respectable amount. Not sure how much of a rise would happen with a V8.

 

[Elbert]

Don't follow how you can use the yota OEM A/C hoses on a 5.7 vortec... On the GM V-8 the compressor mounts on the drivers side (on the high side), while the stock location of the yota compressor was on the passenger side of the I-6. Got any pics that show this? I'm thinking you have to go down the road using custom made A/C hoses.

I should say that on the 99 5.7 vortec V-8... the compressor mounts as described above. Different year models of the V-8 have different locations for the A/C compressor.

 

[ntsqd]

One option might be the street rod blingy braided SS hoses. Can make those up at home. The link above showed some option down that street.

 

[djawahir]

Sorry, I thought the 5.7 vortec compressor location was on the passenger side of the vehicle. Custom hoses are probably the way to go in your case.

 

[Dynosoar]

The A/C amplifier is also wired to the thermister to shut the system off if there is a pressure loss. I run a r12 chevy compressor hooked into the toyota system. Regular braided hose wont work the Freon (r12 & R134) molecules are too small and the system seeps. They have cloth braided braided hose (blue is for freon) that will work. I use Orme Bros. in Northridge Ca. for all my hose needs. They have fast friendly service and are resonablly priced.

Dynosoar

 

[Elbert]

I think I'll see about getting a new compressor next month (old one has been in the weather too long, open)... then get some hoses to work... Maybe will have A/c going by August or so.

 

[ntsqd]

Freon is a bugger, I was thinking of the A/C specific braided SS hoses shown on djawahir's link.
That, or I've been told that my local automotive A/C guy can make hoses. It may not be all that uncommon for A/C shops that specialize in automotive work to be able to make hoses.

 

[Winslow]

I am getting ready for this job myself. As I read above, my understanding is:

1)Wire Tach out from ECU to Negative Coil Wire
2)Wire original A/C clutch wire to ECU A/C demand
3)run A/C request from ECU to GM Compressor
4)Install adapter on back on GM Compressor
5)Run original hoses

Sounds pretty simple. If I 'pigtail' the negative coil wire into the tach wire that goes from the ECU to the tach (which will be calibrated for GM ECU signal) do I still get a correct reading at the tach? Does this cause a short curcuit? I thought the tach out from the ECU would be a + feed and that the coil negative wire would be (-). Thanks for the help. I am no electro-whiz kid. Regards, Winslow