1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

"Placebo" heater upgrade

Discussion in 'Early CJ-5 and CJ-6 Tech' started by colojeepguy, Dec 27, 2011.

  1. Dec 29, 2011
    unclebill

    unclebill Banned

    a sun blasted...
    Joined:
    Feb 17, 2009
    Messages:
    2,358

    option 3
    dress like you are going icefishing.
     
    Rick Whitson likes this.
  2. Dec 29, 2011
    mb82

    mb82 I feel great! Sponsor

    Charlottesville Va
    Joined:
    Mar 17, 2003
    Messages:
    2,715
    Heated clothing? awesome idea.
     
  3. Dec 29, 2011
    Mcruff

    Mcruff Earlycj5 Machinist Sponsor

    Albertville, AL
    Joined:
    Sep 22, 2002
    Messages:
    4,889
    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.
     
  4. Jan 5, 2012
    Mcruff

    Mcruff Earlycj5 Machinist Sponsor

    Albertville, AL
    Joined:
    Sep 22, 2002
    Messages:
    4,889
    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.
     
  5. Jan 5, 2012
    lynn

    lynn Time machine / Early CJ5 HR Rep Staff Member Sponsor

    Huntingdon PA
    Joined:
    Sep 20, 2002
    Messages:
    3,449
    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.
     
  6. Jan 5, 2012
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    4,308
    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!
     
  7. Jan 5, 2012
    PeteL

    PeteL Member Sponsor 2019 Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
    Messages:
    6,345
    "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.
     
  8. Jan 5, 2012
    Smokeater

    Smokeater Sponsor Sponsor

    Browns Summit, NC
    Joined:
    Jun 1, 2009
    Messages:
    125
    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.
     
  9. Jan 5, 2012
    unclebill

    unclebill Banned

    a sun blasted...
    Joined:
    Feb 17, 2009
    Messages:
    2,358
    i insulated the bejabbers out of my 1/2 cab and firewall ect.
    then i put in a heatercraft.
    toasty at -30f
     
  10. Jan 6, 2012
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    4,308
    Doesn't get that cold here :D
    and if it did...I wouldn't be driving the Jeep!
     
    Rick Whitson likes this.
  11. Jan 6, 2012
    jasonjp62

    jasonjp62 Member

    Pennsboro WV.
    Joined:
    Aug 15, 2009
    Messages:
    796
    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.
     
  12. Jan 6, 2012
    duffer

    duffer Rodent Power Sponsor 2019 Sponsor

    Bozeman, MT
    Joined:
    Sep 17, 2009
    Messages:
    2,482
    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.
     
  13. Jan 6, 2012
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    4,308
    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.
     
  14. Jan 6, 2012
    jwjeep60

    jwjeep60 in process

    Sedalia Mo.
    Joined:
    Apr 8, 2008
    Messages:
    561
    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?
     
  15. Jan 7, 2012
    Smokeater

    Smokeater Sponsor Sponsor

    Browns Summit, NC
    Joined:
    Jun 1, 2009
    Messages:
    125
    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.
     
  16. Jan 8, 2012
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    4,308
    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.
     
  17. Jan 8, 2012
    aallison

    aallison 74 cj6, 76 cj5. Has anyone seen my screwdriver?

    Green Cove...
    Joined:
    Nov 24, 2006
    Messages:
    1,764
    You got picts? Looking forward to a report on how the heater works.
     
  18. Jan 8, 2012
    Mcruff

    Mcruff Earlycj5 Machinist Sponsor

    Albertville, AL
    Joined:
    Sep 22, 2002
    Messages:
    4,889
    Mine looks closer to the pm102. I bought mine at napa.
     
  19. Jan 15, 2012
    chuck123wapati

    chuck123wapati Member

    wyoming
    Joined:
    Jun 18, 2008
    Messages:
    761
  20. Jan 15, 2012
    Smokeater

    Smokeater Sponsor Sponsor

    Browns Summit, NC
    Joined:
    Jun 1, 2009
    Messages:
    125
    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.
     

Share This Page

New Posts