Heater Blower Upgrade

[Turbogus]

Hi gang,
Being the member of a couple of Jeep sites I always keep an eye out for intriguing stuff. I ran across this a couple of weeks ago and am preparing to move on it. This mod apparently DRASTICALLY improves air flow for the defroster especially. :shock: One trick is to make certain to get the short shaft PM102 motor for this upgrade. ('73 Chevy Blazer w/350 motor and air conditioning) I've owned a '77 Chevy Blazer with A/C and the 400 (a SIX row radiator on that thing) and that thing blew right hard.

Jeep Heater Blower Motor Upgrade
1979 Jeep CJ-5 Buildup: Heater Blower Fan Upgrade

 

[TLCJ5]

I did that to my "82 CJ5 way back when(probably late "80s)...as I recall it worked well.

 

[Turbogus]

Last night got the battery, battery shelf and heater hoses out/off, dang for being on just over three years those heater hoses were stuck on the heater core tubes tight! Going to try and remove the heater box tonight, hope I can squeeze it out, the roll cage recenly installed probibits movement of the dash (1/4" clearance).

 

[JPNinPA]

:thisthreadisworthle

Picks in the link are small and fairly far away.

 

[Turbogus]

Removed the battery, battery tray and removed the four mounting bolts and got the heater box loose, got to remove the radio for clearance tonight, then maybe I'll get it out. I'll try to remember to take some photos tonight if I have time.

 

[Bnabb]

I did this in my 93 YJ and it works great. The only problem I ran into was I had a ground wire from my old blower and the new one didn't so I ground down a little on the new blower to find bare metal and screwed the ground in there and works great. I have heard some people having to ground down the hole in the firewall but the new blower came with a metal sleeve I just slid it off and it fit right in.

 

[Turbogus]

Great tip, thanks Brennan :beer:

 

[Turbogus]

Got the heater box out last night, true to text in the service manual remove all control cables (I missed one on the end on the first go) and I'd forgotten about the heater box mounting nut behind the air cleaner, but after addressing those issues the box came right out without moving the dash (and roll cage) all I did was remove the glove box and I could see enough to get at any interference. Today I'm going shopping for that 102 fan motor.
So first I removed the odd shaped battery tray I have, not quite enough surface for dual batteries I think.

This gave me access to the firewall in front of the heater,

Then, after finding all the mounting nuts

The heater box came right out.

Removing the perimeter bolts gave me access to the heaver box cavity whereupon I romoved the heater motor and fan

Heater motor and cage fan

 

[Turbogus]

Bought the PM102 motor today at Autozone - $19.99. It's a VDO unit but manufactured in China which concerns me. The motor is the same diameter except for the collar on the new motor, that increases the diameter is this a Chinese swindle?

 

[SteelHeadz]

does this mean you need a squirrel cage too since the shaft is bigger?

 

[drallabg]

Thanks!!! Pics!

 

[Turbogus]

May be Mikey, haven't tried fitting yet. The first new motor I got from Autozone is the one pictured. I stopped by NAPA on my way home last night and looked at their PM102 and despite the different name on the box the motor was configured the same.
I'm just so dubious about this on account of my recent adventure with a broken thermostat housing, stopped by NAPA and got a replacement, it looked the same but after mounting it became apparent that the pitch and angle were wrong enoungh to interfere with other components, returning this water neck to NAPA for a replacement yielded another with a slightly different angle - still wrong, and both stamped "Made in China" going to Autozone it was the same story. This experience has led me to be very cautious about purchasing MIC products, and is leading me to believe I've been had, again.

I've got the 3 1/4" hole saw ready and prepared the jig mentioned on the Terry Howe page and am ready to go, pending confirmation that this motor is correct. Here's the jig;

 

[TLCJ5]

I understand your mistrust of parts MIC...I've been burnt myself. The new motor pictured does look correct,but as you say looking right doesn't always mean it is. It almost gets down to a roll of the dice and/or your gut feeling.Maybe set them up to run on the bench & see if you can tell any difference(RPM,sound,etc..). Good Luck! And let us know how it goes.

 

[Turbogus]

That's my plan for tonight, luckily my van "The Oven" has dual batteries so I'll externally connect them and run 'em up side by side.

 

[TerryMason]

If this works out I'll move it over to the how-to section.

 

[Turbogus]

Cool! Thanks Terry 8)

 

[Turbogus]

Okay gang, here's the news on this VDO stickered (Made in China) beneath the VDO text comparison. I ran both the original motor that was in my Renegade with the brand new VDO tied directly to the batteries on my van. Running the same length and gauge of wire. There was no discerable difference in motor speed. Perhaps my means of testing was flawed, the best I could do was add a cardboard flag to the spindles and the apparent speed seemed the same. However the old, original motor with the flag attached pushed more air than the new VDO mic motor.

 

[Turbogus]

So, went down to the local Knechts AP store and we found through Eugene Service Parts a Four Seasons PM102 made in Canada motor. If this turns out to be similar to that made in China fan motor I'll be singin' the South Park song "Blame Canada" through our P.A. system at the station here.

 

[custmfxwg]

Hey folks. I'm new to the forum, but just did this upgrade a couple of weeks ago, so I thought I'd chime in and let you know you're on the right track and it works like a champ.

I bought the same motor and the only thing you need to watch for is the shaft the squirrel cage bolts to; some of the motors may have a longer shaft, which would cause the cage to hit the heater box.

Make sure you reconnect the defrost ducting, and reconnect the wire under the dash on the right side - above the vent output - that wire controls the three speeds of the motor.

Difference is unbelievable - sort of like from a mild breeze to a hurricane!

 

[Turbogus]

Thanks everyone and custmfxwg I'm clear on enlarging the hole (I've already made the jig for it and have the 3 1/4" hole saw ready to go. I've also clear on using the PM102 short shaft motor as opposed to the PM105 motor, as well as all the associated wiring. Also checking the shaft diameter it appears they are the same, just some error in the clarity of my photos. (a lift of the lynch lid to Mikey :mrgreen: )
I condsidered plurally connecting the fans up to the three way switch wiring, but not wanting to cut into virgin wiring for the sake of a temporary connection seemed unnessesary as I thought using a baseline of 12v and equivalent amperage was more easily obtainable by the means I used. I am open to suppositions that this test is flawed.
My aim is simply to make certain that the blower motor I install is correct so I don't have to remove and reinstall the heater box again and snake it through the mass of wiring underdash that I have for the audio, 11 meter radio, and amps for both. Sorry for my ongoing ponderance, I dig this is getting tedious.