C4 A/C Blower in a C3 upgrade

[mrvette]

Has anybody tried to do this swap into a non A/C car?

Not me, but my old '72 vette squirrel cage and motor assy went into a old camper/motor home with no sweat, increasing the air flow a decent amount....it has aftermarket a/c on it...so the heater/blower fit fine...

:crutches:...all those blowers I have seen were identical in the 70's....

Gene are you taking parts of the vette to put on the old motor home ?

:hissyfit::amazed:

NO I"m not stripping the vette....but I had upgraded the blower to a C4 some time ago, had this 'new but C3' blower motor with the old cage on it....pulled the old camper unit out, the C3 unit fit fine....so had better airflow to boot....funny how old hotrod 'hand me downs' make other vehicles proud....

:3rd:

 

[denpo]

Pigtail for the fan should be:

AC Delco PT189
GM# 12101917

Thanks Larry. That is the same as NAPA ECH-EC116. $12.00. I'll order it Monday. Thanks. (I'll take pics and write a tech on this when I get done)

I'm doing the same upgrade.
Yet have to pick my pigtail (seem to be standard GM connector, I'll try my luck at the scrapyard), but I'm wondering about the wiring, where the extra wire goes, ground?
Also, I've read somewhere about removing the resistor to get full 12v to the blower, what did you guys do?

 

[mrvette]

Pigtail for the fan should be:

AC Delco PT189
GM# 12101917

Thanks Larry. That is the same as NAPA ECH-EC116. $12.00. I'll order it Monday. Thanks. (I'll take pics and write a tech on this when I get done)

I'm doing the same upgrade.
Yet have to pick my pigtail (seem to be standard GM connector, I'll try my luck at the scrapyard), but I'm wondering about the wiring, where the extra wire goes, ground?
Also, I've read somewhere about removing the resistor to get full 12v to the blower, what did you guys do?

YES, one goes to ground and there is no resistor for high speed operation, just a 30 amp inline fuse.....mine was replaced with a 40 amp breaker with the two stud/nutz on it.....and a nice heavy wire too...full alt output directly from the stud....

:clap:

 

[denpo]

Local NAPA couldn't get the pigtails, scrapyard was my savior, got it for free from a '90s Le Sabre FYI.
Thanks Gene, I will scrap the stock resistor.

 

[mrvette]

Local NAPA couldn't get the pigtails, scrapyard was my savior, got it for free from a '90s Le Sabre FYI.
Thanks Gene, I will scrap the stock resistor.

There IS no stock High Speed resistor to scrap....all those resistors/coils in the pressure side of the blower, on top of the a/c coils are for LO speed operation....ONLY....

HIGH speed is controled by a relay that closes giving full voltage....
on my car it was mounted on the a/c box with plug hanging off the bottom, silver top, and two screws....over the valve cover, as I recall....

the wires got scorched over time, claimed the plug/connector, so I moved it up top and soldered the wired directly to the relay.....rot THAT, headers....:hissyfit:

 

[denpo]

Local NAPA couldn't get the pigtails, scrapyard was my savior, got it for free from a '90s Le Sabre FYI.
Thanks Gene, I will scrap the stock resistor.

There IS no stock High Speed resistor to scrap....all those resistors/coils in the pressure side of the blower, on top of the a/c coils are for LO speed operation....ONLY....

HIGH speed is controled by a relay that closes giving full voltage....
on my car it was mounted on the a/c box with plug hanging off the bottom, silver top, and two screws....over the valve cover, as I recall....

the wires got scorched over time, claimed the plug/connector, so I moved it up top and soldered the wired directly to the relay.....rot THAT, headers....:hissyfit:

My bad Gene, I was talking out of thin air, I didn't actually studied the wiring diagram of the blower yet, will make sure not to scrap anything :lol:

 

[Sam Cogley]

I wish I had some photos of my C4 fan install. As there was a big hole punched in my HVAC box (no idea why), I got a spare part from a Corvette boneyard and modified it for the extra depth of the C4 fan instead of using a spacer. That way the entire fan blade is unshrouded and available for improved airflow. The tricky part was cutting the HVAC box and making a jig to hold everything in position while fiberglasing the parts into a new assembly. I'm happy to report that it blows a ton of air, far superior to the stock design.

Added a pic. While the front fender blocks most of the view, the re-glased area can be seen. I didn't bother to clean up the surface, as it's almost impossible to see under that fender and I was busy with other work. The body of the box was spliced to accommodate the extra fan depth, all the way up to the sloped area where the fan opens onto the AC evaporator. Lots of room to flow air, far superior to the stock setup.

 

[beethoven1911]

spacer

Yesterday I recieved my custom spacer. Extremely nice piece.

Today I picked up an 87 Vette Blower and wheel. My choice of Siemens(China) $35.00 or Delco (India) $70. I went with lifetime warranty.:crap:




Now, I cannot find the proper connector. I am usually pretty good at finding this stuff, but not today. All the connectors the houses say will fit are a "no way Jose."
Anybody got a good #? Mike?

who made your spacer for you. Im willing to pay to have one fabricated.....im having a hard time making a decent looking one.

 

[ex9850]

Here it is 2013 and I am looking into this c4 blower in my 78. The system is converted to new gases and blows cold just not much volume. Is someone now selling the spacer for this conversion or kits to convert ? - if so where etc. lol

 

[mrvette]

Here it is 2013 and I am looking into this c4 blower in my 78. The system is converted to new gases and blows cold just not much volume. Is someone now selling the spacer for this conversion or kits to convert ? - if so where etc. lol

Welcome to the motley crew.....

I C 1st post, and so the spacers are easy to make out of 3/4 plywood, but does require a sawzall/recip saw....
I did this conversion years ago, and put my shark on permanent recirculation, removing the interior flapper, and sealing the outside intake permanently closed....but my '72 is a convertible....and I"m in FLORIDA
:surrender:

 

[denpo]

Here it is 2013 and I am looking into this c4 blower in my 78. The system is converted to new gases and blows cold just not much volume. Is someone now selling the spacer for this conversion or kits to convert ? - if so where etc. lol

I guess you know the download area has a template.
I cut mine out of a kitchen cutting board.

 

[BBShark]

Yes. The template is in the downloads section. If you print to scale, you can use it as a template. The thickness will be 1/2-3/4". You want the end of the fan cage to be as close to the hole in the firewall as possible (without touching). To big of a gap will reduce airflow.

 

[jdubya]

Wiring - Three Pins to Two

An old thread, but hopefully someone is listening. My '68 has a connector with a single black wire with one pin (ground) and a second connector with two pins (to two separate wires). I presume the second green wire is for high speed. Do I tie these two green wires together and connect them to the single power wire for the '87 blower?

Thanks

Jeff

 

[BBShark]

I think what you described is right. However you will have only off/high speed. I suppose the C4 controlled fan speed with resistors?

 

[mrvette]

I think what you described is right. However you will have only off/high speed. I suppose the C4 controlled fan speed with resistors?

The only easy way to do it, other than that getting into PWM electronics, and that not available in even the later 80's......

as for the color codes of the '68, MY RECOLLECTION is there was just one wire going to the blower motor.....on my '72, so maybe some wiring changes..??

I have a console switch that makes just two speeds outta the blower motor.....pick a speed and wired it in.....

:lol:

 

[BBShark]

There is a Blower Motor Resistor in the air box for cars built before 69.

https://www.paragoncorvette.com/p-356124-blower-motor-resistor-wo-ac.aspx

I suppose that is what controls the lower speed. So, if you hooked both wires to the same terminal on the C4 motor you would get 2 speeds, right?

 

[jdubya]

Resistor in 1968 - Speeds - Revert to Orig Motor

Correct, there is a resistor in 1968. Unfortunately, I have no idea what purpose it serves. Maybe someone else can support your thinking. Two speeds would definitely be better than one.

Another option would be to put the fan portion on my original motor. It continues to run very well. I've read elsewhere that the way it fastens may be different so that may cause other complications.

 

[jdubya]

Vent Pipe - On the Opposite Side - Route Something?

Still working on this. The new blower has then opening for the vent pipe on the OPPOSITE side of the original blower motor. The picture below shows the original pipe on the original motor and a pencil protruding from the opening in the new motor. Did you route a custom pipe to this opening?

 

[BBShark]

I think I reused the C3 hose and plastic elbow. It could be the C4 hose, not sure. I think its late 70's parts.

 

[jdubya]

Vent Opposite Side?

Great photo. Thanks! Your new vent hole is where mine is on the new blower. I just realized that the old and new blower housings have very different shapes. I think I can rotate the new one about 180 degrees and get close to the old hole position. Hopefully there are no obstructions at the evaporator housing.