Heater Box Question - Motor Upgrade

[zimzimma]

I searched but could not find the answer. Sorry if this has been asked already. I am doing the chevy heater motor upgrade and I was a little aggressive on opening up the hole while it was in the Bronco. I decided I may as well pull the heater box to change the core and reseal. I need to slightly build up the hole I cut. Is the squirrel cage supposed to be on center with the hole in the back of the heater box - not the enlarged hole. The hole for the air intake. It almost looks like the stock squirrel cage was offset slightly although I can't be sure because I opened up the hole already. Does anyone have a photo of the back of the heater box with the motor installed? Or can someone tell me if the squirrel cage should be centered with the hole in the back?

Thanks!

 

[tasker]

BEST PICS i have of mine

 

[Soylent]

If you try to center it then it will hit the on/off flap. Mine is not centered. Doesn’t matter as long as the box is sealed. I didn’t bother cutting out the hole. Just took the box apart and reattached the squirrel cage after installing the motor.

 

[zimzimma]

Thanks! When I was lining everything up i thought I was loosing my mind when it was offset. Looks like it is supposed to be that way. I will make sure nothing hits before I drill the holes.

 

[RV BRONCO]

Heres some pictures of my 68 Bronco heater box with motor before I pulled it. No backside pictures.Looks like you got your answer.More pictures if needed.

 

[904Bronco]

It is not centered, as stated...
The housing has a volute design to it, much like a fire pump. Not a great design for drafting, creating a negative atmosphere as to use the positive air pressure around us to draft water into the pump housing. (Have to use a priming pump to create the negative pressure.

But not exactly the same with the heater box since we are only moving air, but it does help create/build the pressure to force air out the vents.

At Least that is what I remember...

 

[DirtDonk]

Someone needs to create a small extension slot for the square open end, where fresh air enters.
Mimic the factory part so you can reattach the intake hose, but adds a position that you can slide a cabin air filter into.
I’ve always thought we should have filtered air, and have tried various filters up top by the intake. But not really easy or effective. Or long lasting in that location.
That seems like something easy to install in the interior. An easy to replace filter inside would be a great benefit.
Been thinking about different and various heater upgrades ever since I got into Broncos.

 

[pcf_mark]

Someone needs to create a small extension slot for the square open end, where fresh air enters.
Mimic the factory part so you can reattach the intake hose, but adds a position that you can slide a cabin air filter into.
I’ve always thought we should have filtered air, and have tried various filters up top by the intake. But not really easy or effective. Or long lasting in that location.
That seems like something easy to install in the interior. An easy to replace filter inside would be a great benefit.
Been thinking about different and various heater upgrades ever since I got into Broncos.

I like the smell of pine needles when I fire up my heater for the first time each season!

Seriously good idea.

 

[.94 OR]

Someone needs to create a small extension slot for the square open end, where fresh air enters.
Mimic the factory part so you can reattach the intake hose, but adds a position that you can slide a cabin air filter into.
I’ve always thought we should have filtered air, and have tried various filters up top by the intake. But not really easy or effective. Or long lasting in that location.
That seems like something easy to install in the interior. An easy to replace filter inside would be a great benefit.
Been thinking about different and various heater upgrades ever since I got into Broncos.

I brought that up several years ago and have one drawn up for my 3D printer and man did I take a tongue lashing over that "option".
I rebuilt mine with the afformentioned upgrades, sound deadening and the works but no cabin air filter, at this time.

 

[DirtDonk]

Who gave you a hard time about a filter? We've been talking about it for years, on and off, but I don't remember the negativity.
So "enough with the negative waves Moriarty!" as Donald Sutherland would say... Let's get on with it.
Do you still have the design? Was it patterned around a readily available filter size? Lots of good ones out there these days. What with practically every rig on the road being equipped with one nowadays.

Let's get the ball rolling again.
Unless someone's got an improved plenum design for the whole heater box, it's got to be a fairly easily retrofitted design.

Paul

 

[DirtDonk]

One down side I could see (though again, not being negative at all!) would be that perhaps the already weak airflow of the stock Bronco heater could be compromised further by a filter.
Two kinds could be made available then. One is an actual filter filter, like a carbon cabin filter, while the other might be just a mesh screen of such a design as to not impede air flowing into the plenum, but still keeping the rug-rats, mud daubers and errant pine needles out of the area.
Could extend that same design to the other two areas that need filter blockage. The driver's and passenger's side air intakes.

Paul

 

[Torkman66]

Great idea! Might not be practical for a stock heater setup. As you @DirtDonk suggest, the stock flow is limited already. However, thousands of upgrades have been done and will be done going forward. Increasing the airflow through more powerful motors/squirrel cages along with increasing the size of the airflow input would provide enough increased flow to adapt an in-line air filter. It could be part of an overall "Heater Upgrade" kit (motor, cage, intake tube, filter box). It would be best to have it be a plastic box (2"x7"x7") that is mounted vertically right at the kick panel where the air first enters the truck heater tube. Just replace the existing round tube female adapter mounted to the kick panel with a filter box that mounts to the kick panel and has the female tube portion on the outside of it towards the heater box (hope you can picture what I am saying). The front of the filter box could be just like the ones you see inside the back of glove boxes in modern cars. Pop off a lid, slide filter in and out.

For those who have not increased the intake tube size, here is what I did along with the upgraded motor and cage:

I used the stock heater plate and enlarged the hole then adapted a 6" plastic tube for larger air inlet hose.

I did the same thing at the kick panel.

As you can see, the air inlet is much larger.

Used a simple heavy duty 6" dryer tube for the new air inlet. It is very durable, made out of steel coils, l;ined inside by aluminum and outside with plastic vinyl.

Final heater installed. Tons of air at both the feet and at defrost (upgraded fan, cage, and rebuilt heater box).

Because the new heater tube is very compressed after installed (it will expand to 6 feet) it is almost like a sold tube. It is very solid and feet that accidently hit it will not compress it at all. BTW, no noticeable decrease in feet room. It is not anything someone would notice unless it was pointed out. Still tucks nicely up under dash area.

 

[tasker]

NICE JOB!

 

[.94 OR]

I think I had a filter part in mind when I drew this up 5 years ago. I never did get it finished but drawing up a door wouldn't be an issue. My intent was to use the stock screw holes and mate it to the heater box, then the hose adapter to the side of it. I think the issue may have been the obstruction to get the filter straight towards the dash, or straight down towards the floor, so the rear and bottom would need to be open to put the filter in at a diagonal. Just matter of drawing it up now.

 

[Torkman66]

@.94 OR I thinkyou might consider a box that it screwed to the kick panel side flat against the kickpanel. All incoming air would have to pass through it and the existing hose could go from it to the heater box like normal (hose would be a bit shorter). This way the box would be off to the side (against kick panel) and not under the center where feet go. If you are familiar with modern car interior air filter that are located behind the glove boxes, they are small (2"x7"x7") and have a simple snap on plastic lid. I wonder if we could go get one from a pick and pull just to see how one might be made?

 

[DirtDonk]

My original thought process was to mount it outward at the kick panel as well. However, thinking about it more recently. I thought it would be simpler to adapt a new part to the side of the plenum. Where you have your new, larger diameter, hose flange.

With the right design, mounting it at the kick panel should be easy enough.
I like the idea of the two ends being open to allow for an oblique insertion. Or, you could simply make it at a slight angle, inward in one dimension, such as facing the passenger compartment, in order to be able to remove and install the filter and clear things like the loop for the door limiter strap.
Another possible reason for mounting it to the plenum, however, would be for those running a forward roll cage.
Depending upon the cage design, the down leg might block most easy access to a kick panel mounted filter.

 

[Torkman66]

I think you’re right about mounting it to heater box. It would be pretty much universal at that location. I think it could be about the same size square as the metal backing plate on the stock box. A cover on the front could be removed to replace filter by pulling out away from heater towards seat.

 

[.94 OR]

I think you’re right about mounting it to heater box. It would be pretty much universal at that location. I think it could be about the same size square as the metal backing plate on the stock box. A cover on the front could be removed to replace filter by pulling out away from heater towards seat.

That is what I used for the dimensions of my filter adapter box. I ran mine for years without the connecting tube to draw in "fresh" air. As bad as mine leaked air in, between the holes in the floor, bikini top, soft top or misaligned hard top, I just wanted heat and thought if I could cut some of the dust down in the process it would be a win. I did rebuild my heater box this spring and put the connecting tube in but didn't build the filter box, yet.