ac air volume

[ktaylor]

I've got a 86 gmc that has factory ac an I'm looking to get it working righ, I have a new ac compressor,dryer an oriface tube ,I put a blower from a 94 chevy in the truck an I'm looking to see if there's anyway to get more air out of the vents. Do y'all know of any mods or anything to do without buying a 1300 dollar vintage air kit?
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[midgainc]

About the best mod you can do with little money is to disassemble the ductwork and clean it. When you reassemble it, use the foil back duct tape around every joint. The factory fit on these things is horrible, and I would estimate that anywhere from 20-40% of the air leaks through gaps in the joints. You should see a noticeable difference. You should do this even if you decide to boost the blower pressure.

[ktaylor]

Yea that's one thing that I have to do.is there any other blower motor options to get more air flow?
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[midgainc]

I am not aware of a standard aftermarket kit that will boost airflow, but i am certain something could be rigged up (like a faster turning motor) to the blower from another vehicle. I would fix the leaks first, and then see if you like it.

[ktaylor]

10 4 thanks for the replys ill try it
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[TheApocalyptican]

94 blower should be plenty. The ductwork is indeed a very poor fit. I just finished mine. I took the piece the comes right off the air box, and plastic welded all the seams, and put a new thicker seal on the top of it, and then took the piece that goes to all but the drivers left vent, and plastic welded it together. Also put a new seal on the drivers right, and passenger left vent. On mine, I also had to extend the back of the drivers right vent so that it would even reach the new seal. Put some duct tape on part of the flex hose on the passenger vent too.

[ktaylor]

How did you end up plastic welding the duct an what did you use? An how well does your ac blow now that you sealed it up that good?
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[tucsonjwt]

You might want to check to see that the blend door is opening all the way for A/C operation. This is controlled by a vacuum canister. There is a post elsewhere on this forum that goes over the complete rebuild process - can't find it now, but you can search for it.

[TheApocalyptican]

Originally Posted by ktaylor

How did you end up plastic welding the duct an what did you use? An how well does your ac blow now that you sealed it up that good?
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It does blow harder than before. Also blowing a bit colder too. Plastic welded it with a plastic welder. Kinda like a soldering iron with a flat wide tip. The other thing to do is make sure you're getting full voltage at the blower. I've got at least 13.8 volts to my entire electrical system . Before my upgraded ad244 alternator and the sense wire in a location that gets a proper reading and upgrading the main feed to the fuse box, I only got 12.x volts and the blower didn't blow as hard.

[Skunksmash]

Originally Posted by midgainc

The factory fit on these things is horrible, and I would estimate that anywhere from 20-40% of the air leaks through gaps in the joints.

Thank you sir. All this time I was thinking it was something I was doing wrong. Or that maybe my stuff was just too old or something. How would you recommend sealing it all up, short of plastic welding it? I don't have a plastic welder and I'm not real comfortable doing it on my old parts. I'm sure this info would be valuable to the OP as well.

Originally Posted by TheApocalyptican

94 blower should be plenty. The ductwork is indeed a very poor fit. I just finished mine. I took the piece the comes right off the air box, and plastic welded all the seams, and put a new thicker seal on the top of it, and then took the piece that goes to all but the drivers left vent, and plastic welded it together. Also put a new seal on the drivers right, and passenger left vent. On mine, I also had to extend the back of the drivers right vent so that it would even reach the new seal. Put some duct tape on part of the flex hose on the passenger vent too.

How would you recommend sealing it all up, short of plastic welding it? I don't have a plastic welder and I'm not real comfortable doing it on my old parts. I'm sure this info would be valuable to the OP as well. Also, did the 94 blower bolt right up with no fitment issues? And do you use the same fan on the blower? Or do you have to pull the fan off your old truck and put it on the new blower?

[TheApocalyptican]

It's been a couple years now since I did the blower, but when I did mine, it came with the cage. Just took what I bought from the store, and bolted in right in place. As far as sealing the ducts, I originally just did it with silicone. Sealed up just fine that way. My problem was the way the ducts were fitting to the vents, and in the process of trying to fix that stuff, a very small section of the silicone came off, so I said screw it, and decided to plastic weld it all, so I'd never have to deal with it again. Should be no reason why the silicone won't work for a long time. Just make sure to let it cure before you run system.

[ktaylor]

I just found the blend door wasn't open all the way an before when I took the heater box out from under the dash the plastic is wore out for the rod for that blend door an went to get a new box from the junk that's in pretty good shape. I also think I have to warrenty the new compressor I bought because its making a bad grinding noises an is vibrating
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[ktaylor]

and yes the 94 blower motor bolts right in the part number is pm129 at autozone
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[Skunksmash]

Is the blower motor off the 94 a lot louder? Did you notice any difference in noise? Also, are the electrical connectors the same? I may go buy it today.

[TheApocalyptican]

Originally Posted by Skunksmash

Is the blower motor off the 94 a lot louder? Did you notice any difference in noise? Also, are the electrical connectors the same? I may go buy it today.

Didn't notice it being louder at all. Connectors are the same.

[slam59]

This is something I gotta do to my wife's 77 soon. Does the 94 blower fit a 77?
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