MG MGB and MGB GT Tech Talk
Has anyone adapted a modern car blower motor/fan to their MGB heater? I'm ready for an upgrade. Maybe something out of the junkyard?.
My current motor/fan combo works consistently, but the air flow is pathetic. Its like a big dude breathing. All my controls work as they should.
Bigger fan?
Bigger motor?
Bigger fan and motor?
I just need a single speed...ON
There is a GM conversion somewhere on the board, but will require some mod work.
While not a GM part upgrade, the Chicago club did do an upgrade. Here is the link
http://www.chicagolandmgclub.com/photos/b_heater/
That Chicago club write-up was very nice. I am not sure I need the uprated heater core... But I know that I need the bigger fan. I am convinced that there is some cheap big-nasty GM fan motor/fan that would fit with some mods.
My stock fan motor started smoking after I rebuilt the heater system. I bought a new switch, and a new motor from Gordon at the beehive. You would not believe the quality of this motor. Makes the original look like junk. It is a little 426 Hemi, and it just about jumped out of my hand when I put 12v directly to it. I cant wait to hook up Limeys relays and get it going. I will post the results when it is running in the box.
David
Fireo fans have been discussed here. The Fiero motor & squirrel cage can be purchased new at Rock Auto and fit with a slight modification to the heater housing.. If you don't need speed control then the resistor pack is not needed.
Heh. Several good threads on this topic, actually.
http://www.mgexperience.net/phorum/read.php?1,1272666
and the original....
http://www.mgexperience.net/phorum/read.php?1,519704
A couple of the original pics have disappeared, shown below.
Blower resistor I used:
Switch being assembled:
Note that a good stock blower works fine. Mine roasts me. I think most of the complaints are either due to a clogged core or an old motor.
My Dad noticed that Midget heater boxes (71 to 74) are the same pofile but wider than MGA/MGB boxes. I used the top half of a Midget box, with a Midget core, and mated it to the bottom half of my MGA box so I wouldn't have to mod the car at all to fit it in. This also allowed me to fit a 1977 Buick Regal blower motor and impellor, with a relay. Holy cow that thing works!
I needed the extra width for the Regal impellor, but otherwise there's no benefit to the wider box - the MGA/MGB and Midget cores are the same area, just different shape!
I wish I'd heard of the Fiero set up, as it's obviously less work. Nice write up on that, Rick, but I did things a bit easier when fitting the actual motor. I removed the impellor from the motor, set the motor through the cover of the heater box, and replaced the impellor. That way I didn't have to modify the box cover at all! One of the holes on the motor actually lines up with the Lucas motor hole, and I drilled the other Lucas holes in the GM motor flange. The result was quicker, and less damage to the box.
However you do this, it's an excellent mod, and now I do need that 3 speed setup too, as it blows way too hard for most situations when it's on!
The midget heater box I used:
http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=29373
How ironic, Rick, we were just discussing this this morning. ;)
This below link is the one that Rick posted when he did his conversion, same as he posted above, and it is what we followed when we did ours. We ended up using the original fan switch (actually a new replacement unit) as a master switch that turns on a relay that supplies power to the fan switch. I cut up a mid 80's GM HVAC control and just used the fan switch portion which we mounted behind a blanking plug with the center cut out which is mounted on the radio console. ( '71 B) I used the heater resistor, and a bunch of the wiring, out of the same car complete with the high blow relay and now have a four speed heater blower. GM blowers run all the time on low, hence the master switch. I could have changed it to a three speed by moving the wires up one terminal on the switch and leaving the low speed terminal disconnected. I just wouldn't have had the super blow then, which we don't use anyway. I do run it on three quite often depending on the chill factor. This was a worthwhile mod and was relatively easy to do as we already had the heater box out while we were restoring the car. Let me know if you want to see some pics and I'll send them to you or put them up on the web.
Another thought is to also get rid of the OE style heater valve. We put in one off a Dodge PU using some 1/2"-5/8" tapered hoses from NAPA which made it easy to get the valve in without using adapter pieces on both sides of the valve for a much cleaner look.
Joe
http://www.mgexperience.net/phorum/read.php?1,519704
You might try reversing the leads the motor might be turning the wrong way.
The leads are on right. I get decent air flow out of the demister vents, but I can't get anything really out of the foot vents.
I am a little concerned about putting relays and all the extra wiring for a 3 speed switch. I am the King of MG bastardization, but I can't stand wires tie wrapped to the OEM harness. I like it clean and simple. Maybe I can figure something out that is completely based in the interior of the car?
So it seems so far:
Fiero Motor fits with some minor modifications.
It blows too much for just running a single speed
I pulled my heater and cleaned all the junk out of it, cleaned out the "bulb of eye-washing" under the car and sluiced out the distribution plenum. Then, after reinstalling, I added a cheap power relay and direct (fused) wiring from the fuse box.
Lots of crud in the system removed and a fan that audibly turns faster led to quite a bit more air coming through. Sometimes even hot! Worth trying as a first step.
I wonder if your vent cable is adjusted correctly. There is normally quite a bit more flow from the floor vents than the defoggers. Maybe you don't have the diverter pointing quite right?
Larry-
That sounds like a good idea...maybe that's what I will do to start. I have to say though, as I am thinking about this, it would be really nice to have a relay and speeds...food for thought. I just have to decide how I am going to make a clean install that doesn't end up 'busy' looking. I bet if I was really clever, I could hide the resistors in the heater box somehow.
I'm attaching a link to a Picassa web album that has some shots of our Fiero heater fan conversion as well as the heater valve conversion.
Rick, I think that your heater switch mod was probably simpler than ours! But as you said, it was fun doing it. (Gotta keep those brain cells moving you know.) I added captions to each picture to help explain what you are looking at.
http://picasaweb.google.com/diskbrake4/FieroHeaterBlowerAndDodgeHeaterValveUpgradesForMGB
I find it interesting that when I first found this forum in 2006 that installing Fiero heater blowers was a big topic and since we had the car all apart I thought "what the heck" and added it and the heater valve mods to our "to do" list.
Joe
Heater box is a good place for the resistors, actually. They get pretty darn hot. The airflow through the box helps cool them.
I completely agree with putting the resistors in the air flow. What I was getting at is, perhaps I could figure a way to place the entire resistor pack in the heater box and just have a tiny hole for the leads to pass through. I could make a bracket internal to the heater box, and the the only alteration would be the bigger Fiero motor.
Paul
An interesting idea, but you would have to figure out how you are going to prevent the wire insulation from chaffing off due to the motor vibration.
You'd need separate ones to prevent air leaks.
BTW Rick, your new avatar sheds a whole new light on "stick it in your ear"
Ummm, maybe. But there isn't a lot of room inside the heater unit. Maybe if you soldered the wires directly to the terminals to eliminate the extra height for the plug and used a couple of stand offs and correct length screws run in from the back of the unit and mounted in the same general vicinity as where they have been mounted on the outside. I would mount it with the resistors facing toward the front of the car to maximize airflow across them. Anchor the wires with some adele clamps to the inside back of the unit. I'm not sure how to route the wires out of the unit although you could make a hole in the back of the heater box and run the wires through the fresh air intake plenum then through the bulkhead to the heater switch. Properly anchored and insulated and maybe some way to disconnect the wires to simplify removal and replacement. I'm thinking individual disconnects staggered so you're not trying to pull a wad of wires through a small hole at the same time.
Joe