Discussion in 'Early CJ5 and CJ6 Tech' started by colojeepguy, Dec 27, 2011.
dress like you are going icefishing.
Heated clothing? awesome idea.
I can tell you this, the heater motor upgrade probably moves at least twice, probaqbly 3x's as much air, the biggest problem with the factory heater system is the anemic motor thats in the box and how slow it runs. I have done the motor upgrade and hooked it up but never put the resistors in to control the lower speeds, the high speed puts out so much air its pathetic. I would say it at least doubles to triples the heat output. Much, much better than stock. It has been unhooked for the last 2 years as I don't really drive my jeep much in the winter months. I really need to go ahead and finish this setup and use it.
I'm gonna throw this in as a side note so people have an idea of rhe output capability of the stock heater core. I am in the process of replacing the heater core in my 1997 Dodge Dakota club cab. The heater core in this truck heats the truck very, very good. Here are the measurements for the core " 6 1/2" x 9" x 3/4" .
The reason I put this here is the fact that guys are saying the so called Placebo heater is not big enough, the factory heater in the Jeep has over twice the heating capacity of the Dakota heater.
Here are my observations from playing with my heater with the upgraded motor for the jeep.
1 - The jeep factory blower motor is pathetic, it runs far to slow and moves to little air, the GM blower mod better than doubles the speed of the factory blower and output.
2 - If you have the cardboard defrost duct, change it out for the plastic after market and make sure your flexible duct has no holes in it and is straight as can be made.
3 - I have not done this yet but think it would help alot, the metal heater box under the hood is open to the cold air circulating in the engine compartment and probably has a major cooling affect on the core itself. I am going to get some of the automotive insulation they use on firewalls and such and wrap the metal housing and see if it helps, can't imagine it not helping quite a bit.
I used one of these from the rear of an AstroVan, but installed it under the dash. Three-speed motor, two ducts, worked great for heat and defrost.
All good ideas-I did the "farmer thermostat" thing on mine the other day (cardboard in front of radiator) and it's now running close to 200. Temp of the air coming out of the heater is significantly warmer.
I have the plastic def duct already.
I'm definitely gonna try the Chevy blower motor upgrade-it sounds easy & cheap to do-maybe I'll try some insulation on the heater box at the same time.
Thanks for all the input on this one!
"the metal heater box under the hood is open to the cold air circulating in the engine compartment..."
When you get down to it, a Jeep is itself a metal box with cold air circulating all around, and under, and through, it. Little or no insulation anywhere, so comparing to a Dakota or other vehicle is difficult.
Well, it depends on if he's talking about the air coming out of the ducts or the cab itself. The air coming out of my stock heater is warm enough, but there's just not enough CFM to over come the cold air coming in from the cracks and what not. I'm going to try the GM blower mod myself sometime soon. We'll see what we get.
i insulated the bejabbers out of my 1/2 cab and firewall ect.
then i put in a heatercraft.
toasty at -30f
Doesn't get that cold here
and if it did...I wouldn't be driving the Jeep!
My thought on this, The stock heater pulls air from the outside. If you can recirculate the air inside the cab it would work better. the system works to hard to warm 30 or colder degree temps. I put a heater from a postal jeep in mine. And didn't run it to the outside, It heats my JEEP very well.
Doug, are you still running the stock under-seat tank? If not, it is rather easy to fab up a very efficient heater to fit under there that will have you in a Tee shirt at -30 with a leaky soft top. I used a J truck core and a Honda blower (just happened to have). Blows directly at driver's feet and with just about no ducting, it moves a lot of air.
Yep, dual tanks in mine-stock 10 gal. under the seat + a 15 gal. from an int. CJ in the back.
My heater is all stock & original and as far as I know, everything is in good working order. I think I'm gonna do the Chevy blower motor upgrade and call it good-I really don't use the Jeep a lot in the winter, and then only on nicer days.
Is it possible to mod the heater box by placing a hole on both sides in the upper rear most corner near the blower motor so that with the fresh air baffle off it will recirculate Air? or is there a better Location?
Ok, so I bought the Blazer blower motor today. But, it doesn't look like the one in the pic from the site SIDSCJ posted. Mcruff, did yours look like the PM105 http://www.autozone.com/autozone/parts/Continental-A-C-Heater-Blower-Motor/1973-Chevrolet-Blazer-4WD/_/N-ip4n4Z91sgz?counter=1&itemIdentifier=141598_0_0_5281 or PM102 http://www.autozone.com/autozone/parts/Continental-A-C-Heater-Blower-Motor/1973-Chevrolet-Blazer-4WD/_/N-ip4n4Z91sgz?counter=2&itemIdentifier=141515_0_0_4550%2C6774 motor (these are Autozone part #'s). The Binky link said to get with A/C and I did, but it don't look the same as his.
I installed the Blazer motor yesterday-MUCH more airflow than the old one, but I haven't had a chance to drive it yet to see how it actually works out. I bought an el cheapo one from Advance for a 73 Blazer.
I had a heck of a time changing the brushes out to reverse the direction-the wires to the brushes were too short to simply swap them in the brush holder, so a little custom wiring work was required.
I also had a forehead slap moment-the instructions in the link posted above said to use a wood spacer between the motor & heater box. I decided I didn't want to do that, and I cut the Chevy mounting plate off the motor & bolted the Jeep plate on it. The problem is, I used a jigsaw with a hacksaw blade to cut the plate off. Guess where all the shavings wound up? That's right-stuck to the magnets inside the motor! DOH!!
I spent probably 1/2 hour cleaning shavings out of the motor. If I had it to do again, I'd just make the wood spacer.
You got picts? Looking forward to a report on how the heater works.
Mine looks closer to the pm102. I bought mine at napa.
Hey I was just at O reilly's and saw a "turbo fan" on the shelf, its for pumping air into engine compartments on boats but is a 4" round housing with a fan inside. I thought of this post, wonder if you could install it in front of your heater core in the plenum coming from the grill so it would push air through.
I finished my install Friday using the Blazer blower motor. It is for sure a big increase in air flow. I can feel warm air through my defroster vents now. We'll see how well it works when it actually gets cold here, but I think it will be just fine for our temps around here. I don't know if i'm going to do the low speed or not. I might just control it with the temp control.
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