Sartana

Perhaps this is an odd question, but wanted to give it a shot. I have a 1966 with factory A/C. I wish the blower fan was more robust. I have no reason to think it is any less robust than it was when new....but I would like it to blow like a modern car. Has anyone tinkered with this? Can one rebuild the motor in someway allowing for greater RPM's? Thank you in advance for any feedback....

856666

Have you pulled the fan/motor and inspected it - is the fan clean?

LouieM

I recall a thread here (a few months ago?) where the poster tried to do what you want to do, increase the blower output. He even wanted to make the bigger fan from a C3 blower motor work, but it wouldn't fit the C2 confines. I believe the conclusion was that you have to live with the C2 blower output. I was very interested in the article, because I have a factory 67 AC car, so I know what you mean about the fairly feeble blower.

tomy62

From back in the day when I serviced Pontiacs, a common problem was the high speed fan relay going out. All else was normal in the system but the complaint was that the fan just wasn’t moving enough air. I would have that relay checked first. Assuming your Corvette has that relay. BTW, I think you are lucky to have a factory ac car. Take good care of her!

Nowhere Man

If you think about it the heater and AC box and blower is the same size used in the full size GM cars with larger cabins compared to the smaller cabin of a mid year.

Nowhere Man

yes they have one

65air_coupe

I have a factory AC car and find that on high speed with a clean fan it moves enough air but any of the lower speeds don't cut it. IIRC, on high the fan is getting full 12 volts and there's a resister network in the blower housing for the lower speeds. I've considered paralleling a high wattage resister with the medium speed resister to drop the resistance slightly and raise the voltage to the motor at that setting. One of those 'when I get around to it' projects.

GTOguy

This is exactly right. The 'HI' setting bypasses the resistors used for low and medium and allows straight battery voltage to the motor. If you are getting 12.6-14.3 volts to the blower motor, that's as good as it's going to get. The motor could be tired, though.

63driver

A C2 with A/C has four setting on the fan. There is very low, low medium and high. You have no control over very low. As soon as you pull the **** to engage the compressor the fan goes to very low. from there you can click to low, medium and high. If you do not have the four speeds it could be a result of many problems. Most already mentioned here.

davekp78

Could be the evaporator and heater core have gotten crudded up, restricting the airflow.

dplotkin

Engaging the compressor forces the blower on low. There is no very low setting below low. This keeps the evaporator from freezing. This is true of all GM cars of the period. Air flow is not robust because of the size and routing of the ducts. A higher CFM fan would likely cause intolerable noise in the cabin.

Dan

63driver

Incorrect There is a very low speed

65air_coupe

My 65 has 3 fan speeds which can be verified by checking the fan voltage at each setting. Yes, the fan comes on when you engage the compressor but unless something is going on I don't understand, there are only 3 fan speeds.

dplotkin

Kindly point me to the portion of the wiring diagram showing the very low speed setting and switching and I shall be happy to stand corrected.

Dan

63driver

When I turn on my A/C in my 63 the fan starts. Then I can turn the **** on the dash to one of three higher speeds. My buddies 65 A/C car acts the same.

65GGvert

Pulling on the A/C switch activates the low speed setting just like the fan switch. Take a look at the green arrow pointing to the yellow low speed wire coming through the a/c switch from the fan switch. It merely inserts the voltage to the same low speed connection. There is no separate setting in the wiring for "very low". Switching from OFF to LOW should not change the speed of the fan when the a/c is on.

rnixon

There is nothing "wimpy" about the AC system in a C2. Nowhere Man is right it's virtually the same as the system in a full size Chevy . I've enjoyed many comfortable drives, on a hot summer day ,with the Air on and the top down ,in my 67 BB. The blower motor is a service replacement , around 40 years old, and the only problem I have is keeping the interior from getting too cold, with the top up. I'm still using R-12 , but from my experience using R-134A wouldn't make much of a difference

As an example , if i were to lean over, from the drivers seat to open the glove box , the a/c center vent would blow my hat off, and the air flow from the defroster can be felt above the sun visors. If your car won't do that there is something wrong, and it's not the system design, it's a component or components within the system

A resister controls fan speed , but the resistance in a 50 yr. old wire harness can do the same thing. A poor seal on the temp. blend door causes a pressure drop an reduction in air flow to the vents . Loose insulation on the back of the heater core mount can not only disrupt air flow, I've actually seen it stop a/c air flow . A poorly sealed heater box ,on both sides of the fire wall, relying on 50 year old gaskets an strip caulk , with a missing screw or two ,gently distributes more air to the engine bay, on the outside, and the the floor on the inside , than to the vents

Don't automatically condemn the blower motor , it's usually not the problem . No body would argue with rebuilding a 50 yr. old engine , the same applies to the heater a/c system , if you want it to work like new , then renew it, or reseal it as best you can.

65air_coupe

When I first purchased my 65 AC coupe, I removed the dash and went through the heater/AC box and renewed all the gaskets, cleaned the blower wheel and resealed everything and although that's been 40+ years ago, I never remember that much air flow out any vent. In the Florida heat, I usually have to have it on high to keep it cool enough.

63driver

Well, I studied the chart. Today I started the car to cycle the oil in the A/C system and went for a ride. It may be my imagination. When I pull the lever to turn on the A/C the fan does come on low. Here is my imagination. When I turn the fan speed **** to the first setting I swear the fan speed increases, but not by much. The next two fan speed setting are noticeable higher.

Anyway, the diagram is the diagram.
Cheers