CJ 7 Heater upgrade - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 08-25-2000, 09:20 PM
**DONOTDELETE**
Guest
 
Posts: n/a
CJ 7 Heater upgrade

Despite the fact it's 95 degrees out, I have my heater unit out of the rig working on the Terry Howe upgrade, which you can find here:

http://www.jeepwire.com/tech/interior/cjheater/

Anyway, I have a small problem and could use advice.

1. I tried a 73 Blazer blower motor for a truck with the 350 and AC: the flange fit great and the fan fit over the shaft, but the shaft was way too long, which meant the fan bottomed out inside the heater housing, leaving the flange over 3/8" from seating.

2. I had NAPA check: the same blower motor was used in both AC and non AC trucks that year. NAPA had no more alternatives for me.

3. Schuck's Auto found me a blower motor (they catalogue it for a 74 GMC pickup with 350 and AC) that does much better: the flange mates up fine and the shaft is much shorter, although still too long. The interference with the fan only prevents the flange from seating by about 1/16" with this unit.

I figure I've gotta go with this one, so the question is:

Do I cut on the internal partition that is interfering with the squirrel cage fan? It could be cut or rasped by enough to give clearance.

Or do I find somebody with a drill press and use it and a 1 1/4" paddle drill bit to shave enough off the center of the fan so it'll seat deeper on the shaft, thereby eliminating the interference?

Sorry this is not clearer. I could show you by drawing on napkins if we were having coffee, but I have no way to use graphics here. I think anybody who's worked on a CJ heater unit, 77 to 86, will understand.

Any help appreciated.

<font color=blue>45-auto
Bone stock '81 CJ7.
"You can always see it coming. But you can never stop it."
-- Cowboy Junkies.
</font color=blue>
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 08-25-2000, 10:40 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: CJ 7 Heater upgrade

Thats strange about the blower from the 73 not working.... I just put mine on a couple of weeks and no problems thus far. I got mine at Trak Auto and works just great.. Sorry I have no suggestions though about your problem just thought I'd put in my .02cents

post #3 of (permalink) Old 08-25-2000, 10:52 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: CJ 7 Heater upgrade

Jake-

You wouldn't happen to have parts numbers handy, would you?

Yeah, it seems strange that the blower motor NAPA sold me for a '73 Blazer, 350 and AC wouldn't fit, but apparently yours did.

I'm really puzzled, too, because the webpage I referenced above says that no modifications to the heater housing should be necessary.

I can hardly believe that 73 Blazers had such loose tolerances that the first one I got had a shaft that was damn near half an inch too long. But there you have it.

I feel fortunate I decided to get this done during the hot weather. Lots nastier trying to do this out in the cold!

<font color=blue>45-auto
Bone stock '81 CJ7.
"You can always see it coming. But you can never stop it."
-- Cowboy Junkies.
</font color=blue>
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 08-26-2000, 12:09 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: CJ 7 Heater upgrade

I bought my motor from Advanced Auto parts and it worked great. I just had to enlarge the hole in the firewall and run a ground wire because I put a glass tub on. Maybe you could compensate for the 1/16" by shimming the motor at the firewall with gasket material. I wouldn't modify the heater box unless its a last resort. Hope you get it worked out.

post #5 of (permalink) Old 08-26-2000, 12:24 AM
 
Join Date: Sep 1999
Posts: 2,137
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: CJ 7 Heater upgrade

I bought the '83 Blazer motor from NAPA ..
BUT my '83 CJ-7's fan was broken due to a pencil fallen down the cowl vent.
The dealer replacment fan was of a much more effecient fin design but was larger (axis wise) than the original.
Hint: It's a heck of a lot easier to cut the inside half-round hole on a plastic fan than to grind on a motor shaft.
Some (stepped) fin cropping may be needed to clear the circular ducting.
Hint 2: Bolt your heater assembly together and spin (with 12v juice) the new, faster/stronger motor/fan before you do final assembly ....
then mount your fan housing assembly into your Jeep's tub...
Then, if the final bolt-in does not deform the heater housing, it's hurricane city!
See my Jeep site for pics and more details....

JAF
http://www.monsterslayer.com/jeep
Jaffer is offline  
post #6 of (permalink) Old 08-26-2000, 08:33 AM
Keyboard Implanted
 
Join Date: Sep 1999
Location: Southeast Iowa
Posts: 6,394
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: CJ 7 Heater upgrade

[img]/wwwthreads_images/icons/frown.gif[/img] We ran into exactly the same problem with our '79 CJ heater. The fan motor positioned the squirrel cage too far into the housing. We had to grind the motor shaft A LOT before it would clear. What's up with that? Why the difference. Why do we have to struggle while the rest of you guys skate?[img]/wwwthreads_images/icons/crazy.gif[/img]

CJDave
Quadra-Tracs modified While-U-Wait by the crack moonguy[img]/wwwthreads_images/icons/wink.gif[/img] Quadra-Trac Team.[img]/wwwthreads_images/icons/tongue.gif[/img][img]/wwwthreads_images/icons/smile.gif[/img]
CJDave is offline  
post #7 of (permalink) Old 08-26-2000, 10:55 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: CJ 7 Heater upgrade

Guys-

Thanks for the thoughtful responses from one and all. I have drawn some conclusions here and would appreciate having my logic checked, as well as maybe getting some additional info from those whose new blower motors slid into place as easily as Al Gore getting next to a wealthy foreign campaign contributor.

First off, it looks like the source of the new blower motor is critical: CJDave and I both found the shaft was 'way too long. CJDave doesn't mention where he got his, but the first one I had was what NAPA catalogued for a '73 Blazer with the 350 engine: NAPA part # 455-1076, which is the same for AC or non-AC. CJDave took the grinder to the shaft and crafted a good fit with cunning and know-how. I took the blower back to NAPA.

I then got a Schuck's blower motor (their part # 33892) for a '74 GMC pickup with 350 and AC. It fits in all respects except the shaft is still about 1/16" to 1/8" too long, meaning when you slip the blower/fan unit into the housing it bottoms out, leaving 1/16" to 1/8" of gap between the blower flange and the mating surface on the heater housing.

Contrast this with Garyl, who got his blower motor at Advanced Auto Parts, or JakeCJ, who got his at Trak Auto Parts. They had less trouble than an intern trying to get molested at a Clinton rally.

Finally, there's Jaffer, who went to an '83 Blazer blower motor which had a difference on the shaft flats, coupled to a dealer replacement squirrel cage, which was longer in the axis than stock. He crafted a custom unit by honing and die grinding various parts of the parts.

It looks to me like the heater housings on early 70's Chevy trucks were such that aftermarket manufacturers have a lot of latitude in terms of the shaft lengths they offer, so some of those manufacturers are establishing shaft lengths that allow them to catalogue the same replacement unit for other rigs entirely.

Therefore the source of the blower motor is critical to whether it will fit into a stock CJ7 housing.

Finally, we get to the end of this book! Can anyone who had a blower motor slide in with no trouble at all please post where you got it, if possible who the manufacturer was and what the part number was? In other words, do any of you have a shop trash barrel so big that the parts box is still available down at the bottom?

Thanks again.

<font color=blue>45-auto
Bone stock '81 CJ7.
"You can always see it coming. But you can never stop it."
-- Cowboy Junkies.
</font color=blue>
post #8 of (permalink) Old 08-26-2000, 05:33 PM
 
Join Date: Sep 1999
Posts: 1,066
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: CJ 7 Heater upgrade

I am pretty sure I got mine from discount auto parts and it went right in but I can't find the reciept to get a # off it,biggest pain I had was the hole in the firewall,I did mine with a mapp/oxygen torch which kind of set the body putty on fire [img]/wwwthreads_images/icons/smile.gif[/img]I also made new valves for the inside of the box and a new core ,after removing all the dead leaves and stuff (like the team rush landfill cleanup [img]/wwwthreads_images/icons/wink.gif[/img] )and sealed the box together with some kind of sealer/putty....man I am gettin..... SEA-NILE.....
I also seem to remember a big difference in price from pep-boys and discount auto on both the heater core and blower motor.

Ray
Learn to let go of what does not serve you ,but forces you to serve it
why does everyone ask if I am gonna paint it ?
unhumen is offline  
post #9 of (permalink) Old 08-26-2000, 10:04 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: CJ 7 Heater upgrade

End of story: the new blower motor is in and it does increase the airflow a lot. It blows like Sarah Brady in a meeting with Bill Clinton.

It seems like the NAPA blower motors were too long in the shaft, as CJDave noted his was. The one that finally fit was some kind of Canadian aftermarket unit and I owe you all an apology, but: I installed it and now I don't have the maker's name or the number! They are buried under the battery tray and I'm damned if I'll pull stuff to get 'em.

The best check on whether you have the right one is: pull the old one and take it to the parts store. Get the new one out of the box. Hold the two of them together face-to-face and offset, each shaft tip resting on the other motor's flange. If the flanges are parallel, the new one has the proper shaft length to avoid interference. Other than that, the shaft diameter and flats need to be right and the flange needs to have five holes in the right places. Every motor I looked at was OK that way.

The one that finally did it required absolutely NO modification to itself or to the heater box or fan. It just fit and it runs like a top.

As far as cutting a bigger hole in the firewall, it wasn't hard at all. I used one of those new kinda hacksaws that just hold the blade like a knife handle, instead of having the traditional bow grip. Used a 32 tpi blade.

Since the old hole was 2 7/8" diameter and the new motor was 3 1/2" diameter, it's obvious the hole needed to be enlarged by 5/8" diameter. I chose to make sixteen radial cuts with the hacksaw, each 5/16" of long. It took all of five minutes. Then I bent the resulting tabs out into the engine compartment with vice grips. It looks really tidy and it allows a good seal.

This is a very easy Saturday project, once you have the right motor. That seems to be the trickiest part of the whole thing.

<font color=blue>45-auto
Bone stock '81 CJ7.
"You can always see it coming. But you can never stop it."
-- Cowboy Junkies.
</font color=blue>
post #10 of (permalink) Old 08-27-2000, 01:28 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: CJ 7 Heater upgrade

If you get the motor shown for a late model YJ, it has the large motor and the correct fan spacing, It also has a dual wire connector, allowing a separate ground to be connected directly to the - on the battery, decreasing the voltage drop.

Hope this helps, good luck!

Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome