cutting heater box

[swynx]

has any one modified there a/c heater box and actually had it work worth a crap? i pulled the a/c deal out and plugged the holes where the lines came out, still dont get enough air flow to even defrost the windows within an hour, only time the heat comes out decent is when im on the highway.

im assuming its the shape of the new box that is my restriction. was thinking about shaping it more like a non a/c box.

 

[RonD]

The evaporator being removed shouldn't effect air flow

All air coming from the fan blows(blew) thru the evaporator and then comes to the Blend Door, it either routes air thru the heater core(HOT) or around the heater core(COLD)

1994 Blend Door is cable operated, you can see, and adjust, cable above glove box

So is the Air flow the issue or is the HEAT of the air the issue?

The fan pulls air in from the cab side of firewall, either from the outside air vent or the cab vent, there is a vent door for this, it is used in MAX AC(sucks in already cooled air from cab), or if you have a "Re-circulation" setting
In normal settings its sucks in outside air from under the cowl

Select MAX AC(if 1994 has that) or re-circulation and see if air speed gets better, fan sucking air in from inside the cab

Pull out the resistor block and see how air flow is there with fan on high, that's on the opposite side of where evaporator was, if its not blowing hard then problem is on the fan side, maybe intake air is being blocked

 

[swynx]

the air worked fantastic until i did the sohc 4.0 swap, and had to modify the box. after that i get alot of fan noise, but not much air. i can barely feel it on my hands. you can feel it switch between foot/vent/defrost. going down the highway at 45 it will cook you out, even if you turn it off, you have to turn the blend to a colder setting to stop it.

i have checked to see if theres a blockage somewhere but there is not one that i can find.

ill have to try the max ac option with heat tomorrow

 

[swynx]

got a wild hair in me and decided to reshape the box to resemble a non a/c box, its slim with a direct air channel, felt abunch of air escaping around the edge of the blower motor, as there was no seal there, sealed up that as well as added new seal around the entire box. i can at least now feel the air about a foot away from the vents. still not as good as it was originally. but definitely better. should defrost the windows now atleast. i think its probably as good as its going to get.

i believe its the blower motor resistor, thats mounted to the plastic. it has the windy coils on it. is mounted directly in the path of the air. so im assuming that should work out.