[Bobalong]

Been wayyy to many years since I replaced my A/C blower motor, 70 GTO. The hood is off and the engine is out being rebuilt. What's the easiest way to get access to the blower without cutting out the access panel in the inner fender ?
Is it possible to drop the inner fender enough to gain access without removing the outer fender ? I'm trying to do this without having to realign the hood, fender, door clearances when finished. IF that's possible, plus I'm getting lazy in my old age.

[Formulajones]

The inner fenders will come out without removing the fender, just takes a little finagling. I've had the inner fenders out for blower motors in a few F-bodies and A-bodies, it's not all that bad to do.

[HWYSTR455]

I've had to take the tire off before to get the inner fender out, but it's not too bad. You can get it out without taking the tire/wheel off, but the amount of time and frustration, it's easier to just accept the fact that you're going to have to take it off.

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[78w72]

if the motor is out, ive had no probablem taking the entire a/c box off the firewall with wheel wells still in the car, on a 2nd gen firebird. seems a gto would have even more room to do it.

[mgarblik]

I just have to tell this story and it is related. When I worked as a technician at a Pontiac Dealer in 1979, a customer came in with a Brewster Green 4-speed SD-455 Trans Am for a blower motor. The FACTORY service manual said to CUT the inner fender to gain access and then seal it up when done. I just couldn't do it. I knew how valuable those cars were going to be and they already had quite a following in 1979. I called the customer and explained the situation and he agreed to pay me $50.00 cash on the side to pull the inner fender. He was a smart guy. Otherwise, I would have had to hack up an SD car. Even the factory didn't give a damn about doing things right, just get it done, period!

[Bobalong]

Originally Posted by 78w72

if the motor is out, ive had no probablem taking the entire a/c box off the firewall with wheel wells still in the car, on a 2nd gen firebird. seems a gto would have even more room to do it.

Good thought, so I went out and looked to see if that would work . . . . . .seemed like a good idea but no go for A body. Heater hose nipples, AC box and rear of inner fender all tucked in there real tight.

HWYSTR455 I think has the best suggestion, remove the tire, make some room and start turning wrenches. . . . .then off to Autoworld to see what blower motors of that size, but from 80's (where more RPM is made) can be fabricated to fit.
I'm looking for a faster blower speed to increase my A/C - Heater air flow.
Evaporator is clean, duct joints have been taped . . . .just needs more CFM
Will report back when I find something.

[78w72]

tucked in very tight on f-bodies too, but sure enough it comes out. once loosened you have to finagle it off the heater core tubes as you pull out & to the driver side. but when i do this its usually on a parts car that is getting stripped so i dont care about being rough with it & probaby had to tweak the heater core tubes a bit more than you would on your own car.

good luck.

[428GTO70]

Originally Posted by Bobalong

off to Autoworld to see what blower motors of that size, but from 80's (where more RPM is made) can be fabricated to fit.

You may be surprised to know that the same blower motor that goes in our 70 GTO was used all the way into the early 90's (Oreilly's.com compatibility chart shows over 15000 applications for the PM102 blower motor). I think the cars that seem to blow more air is more of a factor of the design of the system rather than the blower motor.

Also making sure you have good grounds and power connection to the blower motor, as well as good seals on the blend doors etc. Of course a new blower motor may still be in order, but just getting the right one for your car and making sure you have good connections can help a bunch.

Also I will also say that the best attack for changing it is to pull off the tire and just pull the inner fender out. It can be done and back together in under a couple hours easy.

[track73]

Cutting the inner fender is what I learned back in 73. I took off the inner panel to change the heater motor on my T/A only to fine out that the ground wire was off.

[Tom Vaught]

300 Grams of C4 will REMOVE it in about .00001 seconds.

Tom V.

[Bobalong]

SUCCESS. . . .Was dreading, fretting how to get to this motor without a gazillion screw and fender alignment issues when putting it back together. In less than an hour, removed the tire, a dozen bolts and some creative wiggle and tugging and the inner fender came right out.
Now begins the hunt for the highest RPM similar motor I can find.


Quote from 428GTO70:
You may be surprised to know that the same blower motor that goes in our 70 GTO was used all the way into the early 90's (Oreilly's.com compatibility chart shows over 15000 applications for the PM102 blower motor). I think the cars that seem to blow more air is more of a factor of the design of the system rather than the blower motor.


I'll report back when I choose my replacement. In the morning my first NAPA visit locally will be looking for a 1997 chevy pick up truck blower, internet pics indicate it is the pm102 mentioned above.
Also I am having doubts about the actual squirrel cage that is on the motor. I remember back in the early 80's replacing this cage from a local parts store, my oem was cracked plastic and all they had was metal. Not sure now that I look at it, that it's the right size.
And finally, I know the evaporator is clean and clear of debris, but there's some connections, and places that could use a little sealer & foil tape to prevent air leaks.

[428GTO70]

The one in my 70 GTO is a metal squirrel cage also, and mine had an issue where the cage part had come loose from the center that attached to the blower motor shaft. This made the cage spin free, separately from the motor shaft so not only did it sound horrible it would not blow worth a crap. I assumed my blower motor had a bad bearing or something but it was the cage. Something to check while its out.

[HWYSTR455]

True on the squirrel cage, they can get loose on the shaft.

I think the design of the cage limits the capacity of air, and unless you change it, regardless of how fast you spin it, it's always going to be the same.

Another area you should verify is clear, sealed, and operating correctly is the fresh air door in the kick panel area. There's a soft rubber elbow that goes from the firewall to the flapper door area that if it is collapsed, it won't flow jack. (maybe I will post a pick of one out of the car as an example).

.

[Bobalong]

Originally Posted by HWYSTR455

True on the squirrel cage, they can get loose on the shaft.

I think the design of the cage limits the capacity of air, and unless you change it, regardless of how fast you spin it, it's always going to be the same.

Another area you should verify is clear, sealed, and operating correctly is the fresh air door in the kick panel area. There's a soft rubber elbow that goes from the firewall to the flapper door area that if it is collapsed, it won't flow jack. (maybe I will post a pick of one out of the car as an example).

.

I agree. The fins on the existing cage just don't seem large enough.

[Bobalong]

UPDATE : no photos yet. Well as was mentioned earlier, the PM 102 blower was used in a gazillion GM vehicles from the 70's up thru the early 90's. So my original idea of merely switching to a newer PM102 application would net the same exact motor.
BUT. . . . .we found that the 81 Caprice used the same blower wheel as the PM102 if without AC. And a wheel that is 3/4 of an inch bigger WITH AC.
So now you know where I am going with this . . . . . the motor for the Caprice is very similar, so we hooked it to a battery and compared a new Caprice blower against a new 102 and the sound the Caprice blower had slightly higher RPM.
So I have the new Chevy motor, and the slightly larger diameter blower wheel will be here today for a test fit.
Mounting plates are similar enuf that some slight fabrication will make the install relatively simple.
Pics to follow.

[HWYSTR455]

I'm curious to what your findings are, something to keep in mind, useful info for later upgrades/projects.

There are a ton of wheels you can buy, Grainger and other supply places have listing of wheels for size and direction, as well as RPM range and CFM.

http://www.grainger.com/category/ecatalog/N-1z0dk6u

With a little homework, some trial and error, you could come up with something that would certainly have a higher output/volume.

During a quick search, found something interesting, out of a 69/70 service manual, a rare option called 'Power Flow' ventilation. They're small blower motors that go in the kick panels which increase vent output. (see attached pics). Maybe a variation of this concept would work.

.

[Bobalong]

Left is pm102, right is replacement. Assuming pic posts

[rexs73gto]

There was a lot of discusion on this subject on the A-Body site as our cars always had slow blower motors. What we came up with was the way to make the motors go faster & blow beter was the differecne in the blower resistor & th way there blower switch is. All the newer cars have a 4 speed switch & our old cars have only a 3 speed switch & in the blower resistor there is less resistance which makes the blower go faster when on. I don't remember the excat bloer resistor to use to make them go faster but i do remember that there was a fix that did make them perform better. The blower motors are all about the same but there is a blower motor that was used to help speed up the air flow , but I can't remember which one & which parts were used to fix it. If you can get to the abodysite.com & do a search you may be able to find the fix.

[Bobalong]

Well I did some mock up testing tonight on the new blower motor & wheel. The new motor is definitely a higher RPM motor than the stock motor. And the base plate screw holes seem to match, but the plates are shaped differently. Go figure.
The replacement blower wheel I got is 3/4" larger diameter, which would have been great, but it is deeper, so it's a no go. No room.
So I have decided to go with the stock wheel, and the Caprice higher RPM motor and just enjoy the higher RPM, and assume there will be increased CFM, (can't be less)
So only modification will be making a base plate spacer to move the motor out 3/8" since the motor is that much farther in on the base plate. Confusing I know.
In other words looks like it should just bolt up, but there is a difference is the depth of the motor on the mounting plate which can't be compensated by moving the fan on the shaft.
Will report back after I find a suitable 3/8" spacer for the base plate.
Stay tuned because when this is finished I'll have a non scientific, non measurable but honest assessment of my blower output. Either I wasted my time and a few bucks or I made a noticeable difference in air output.

[Bobalong]

Originally Posted by rexs73gto

There was a lot of discusion on this subject on the A-Body site as our cars always had slow blower motors. What we came up with was the way to make the motors go faster & blow beter was the differecne in the blower resistor & th way there blower switch is. All the newer cars have a 4 speed switch & our old cars have only a 3 speed switch & in the blower resistor there is less resistance which makes the blower go faster when on. I don't remember the excat bloer resistor to use to make them go faster but i do remember that there was a fix that did make them perform better. The blower motors are all about the same but there is a blower motor that was used to help speed up the air flow , but I can't remember which one & which parts were used to fix it. If you can get to the abodysite.com & do a search you may be able to find the fix.

With the blower in the high setting there is a straight shot of 12 V provided via the wire from the alternator, to a relay on the firewall to the motor. The other speeds routed thru the pig tail resistor aren't of concern to me as long as they work.