CJ-5 Heater Fan Upgrade Questions

On Sun, 18 Mar 2007 12:48:30 -0400, Mike Romain >
wrote:

>The are both stock GM items. AMC used a GM heater setup with the same
>resistor pack which is why the larger motor fits right in and to the
>blower cage also.


Thats cool, I just thought I would mention it.
-----------------
TheSnoMan.com

Thanks Mike. Yes, I do have a back-fire problem. I forgot to add that my
CJ-7 has a Chevy 350 w/ Edelbrock 600 cfm carb (Manual Choke), and an MSD
ignition.

I either have a timing/timing chain issue or I may have inadvertently caused
the problem. I have a leak on my Brake Booster, so I disconnected it and
sealed off the vacuum. The other day I took the Jeep on the highway and (So
I would have more responsive Brakes) I reconnected the leaky booster. After
about 10 miles down the hi-way...BOOM...it backfired and the entire Jeep
shook. So I pulled it over and it died. I did re-start the engine and
after about 30 seconds...BOOM. So I shut it off and had it towed to a
garage. Again, I'm not sure if the leaky booster caused a problem w/ Vacuum
e.g vacuum advance/lean condition..or, my worst fear is the timing chain
broke/slipped.

Where did you post the Meter walkthrough?

Thanks Mike and SnoMan


"Mike Romain" > wrote in message
ng.com...
>I just clicked on something.... You have the backfire issue in the other
>group right?
>
> The orange wire from the choke sometimes hits the exhaust manifold near
> the back which will cause that. The Ford coil connectors are pretty
> crappy and either could have been moved or dinged when you were in there
> trying to bolt the heater back on. Even a plug wire.
>
> I also have posted a meter walk through for you to test your connections
> so you don't have to tear everything open on your alternator harness.
>
> Mike
>
> Anthony T wrote:
>> Mike,
>> not having the dash off wasn't the problem (I agree it would be easier if
>> it was off). My problem was the hard plastic duct that runs from the air
>> intake on the hood down to the heater assumbly. It was this duct that
>> caused my problems. You are correct though, it's easier to see what's
>> going on with the dash off.
>>
>> "Mike Romain" > wrote in message
>> g.com...
>>> Just an FYI.
>>>
>>> If you have the dash off, the cussing time will be cut in half at least
>>> 'And' the heater motor will fit straight through the nice new round
>>> hole... let alone how easy it is to hook up all ducts...
>>>
>>> I think it is worth the 'extra' time to pull the dash.
>>>
>>> Mike
>>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>>> 88 Cherokee 235 BFG AT's
>>> Canadian Off Road Trips Photos: Non members can still view!
>>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>>> (More Off Road album links at bottom of the view page)
>>>
>>> Anthony T wrote:
>>>> James,
>>>> I'm not sure if your still looking for advice on this mod. I just
>>>> recently moded my blower motor. It's a fairly cheap upgrade but a pain
>>>> in the ass to complete.
>>>>
>>>> I bought the upgraded motor from Schucks, part # 35587 (that's the
>>>> correct GM upgrade) I paid $30 for the motor, new.
>>>>
>>>> You do not need to remove the dash or seats to get the heater housing
>>>> out. I did it at 45 years old. However, you need be able to contort
>>>> your body a little.
>>>>
>>>> Getting it out is the easy part. 4 nuts and it's out.
>>>>
>>>> Once out, unscrew the numerous screws on the back of the heater housing
>>>> and you get to all of the innards of the heater hosing.
>>>>
>>>> Absolutely replace the heater core (Schucks part # 399210 for $40.).
>>>>
>>>> Replace your old blower motor and heater core.
>>>>
>>>> Now the hard part. Lining up the flapper ducts and the heater housing
>>>> and buttoning it up. That took a little finesse and time.
>>>>
>>>> Now the really hard part...expand the hole to fit the new blower motor.
>>>>
>>>> Read this and you will have complete success making the hole larger and
>>>> it will look like a professional install;
>>>> http://www.jeeptech.com/body/heatsup.html
>>>>
>>>> I had to buy a 3 1/4" hole saw at Home depot for $20
>>>>
>>>> Do not make the same mistake I made: I measured perfectly, and I made
>>>> a perfect hole. However, I couldn't get the friggin heater assembly to
>>>> fit back in. So, I absolutely hacked my beautiful hole into a jagged
>>>> octagon using a dremmel tool (it looks like ****) but the assembly more
>>>> easily fit back in.
>>>>
>>>> As I look back on this I realized, I just needed to finesse the heater
>>>> assembly to line up with the holes. Have patience (unlike me) and give
>>>> it a good push and it will fit in nicely
>>>>
>>>> Total Cost for the project, including the hole saw: $90
>>>> Total time...about 6 hours as I couldn't get it to fit back in. Have
>>>> two or three friends help you line up the holes.
>>>>
>>>>
>>>>
>>>> "James" > wrote in message
>>>> . ..
>>>>>
>>>>>
>>>>> There were a number of posts and website reviews on upgrading the
>>>>> heater fan
>>>>> blower motor for the older vintage cj-5 Jeeps. My Jeep is a 1980
>>>>> CJ-5.
>>>>>
>>>>> I have read all the posts that I can find on this, and I would like to
>>>>> summarize some questions that still remain for me as I prepare to
>>>>> assist my
>>>>> mechanic for getting ready to do this for me.
>>>>>
>>>>>
>>>>> 1. Motor model. I note that the web article on Off-Road.com
>>>>> says to
>>>>> ask for a motor for a 1973 Chevy Blazer / 350, with a/c. Other
>>>>> notes say to ask for the "normal" fan motor, not the "premimum" one.
>>>>> It
>>>>> is said that the shaft on the "premium" motor is too long. I wonder
>>>>> how
>>>>> you can be confident that you have the right motor if they only list
>>>>> one
>>>>> (not a "normal" and a "premium" one) ?? Also, I see that Mike
>>>>> Romain
>>>>> indicates that the "right" motor to ask for is for a 1972 Chevy
>>>>> Blazer
>>>>> (not a 1973 as indicated on the website article. ). I wonder if
>>>>> anyone
>>>>> bought a "correct" size motor from NAPA, and could just give me the
>>>>> NAPA
>>>>> part number ?
>>>>>
>>>>> Any other comments on making sure I get the right size motor for my
>>>>> 1980
>>>>> CJ-5 Jeep?
>>>>>
>>>>>
>>>>> 2. Gasket? Will I need to fashion some kind of gasket when the new
>>>>> motor
>>>>> is put on ? One poster said he had a terrible time getting a new
>>>>> gasket
>>>>> made. Can I buy a gasket of some sort, or will the old gasket work
>>>>> if
>>>>> care is taken ?? Any comments?
>>>>>
>>>>>
>>>>> 3. Heater core. I plan to have this job done from the firewall side,
>>>>> and
>>>>> not take the dash out. Can the heater core be easily removed from
>>>>> the
>>>>> firewall side ? Will it be obvious to my mechanic if the heater
>>>>> core
>>>>> needs replacement, or boiling out ? If this is such a hard job,
>>>>> wouldn't
>>>>> it just be quicker/easier to buy a new heater core ? What is the
>>>>> ballpark
>>>>> cost of the heater core? Remember, this is a 1980 Jeep, but the
>>>>> core is
>>>>> not now leaking, but I don't know how good the flow is.
>>>>>
>>>>>
>>>>> 4. On my 1980 CJ-5, would it be easier in the long run to remove
>>>>> the
>>>>> battery tray ? I have the standard battery and tray.
>>>>>
>>>>>
>>>>> 5. Proper saw for enlarging hole. Which is best, a jigsaw,
>>>>> scroll saw,
>>>>> or a reciprocal saw with a thin blade ?? I know that a hole-saw
>>>>> will cut
>>>>> a cleaner, more precise hole, but isn't it true that this can only be
>>>>> done
>>>>> from the dash side ? (if so, I don't really visualize why???)
>>>>>
>>>>> -------------------------------------------------
>>>>>
>>>>> Again, I am not a mechanic, but I work closely with my mechanic and he
>>>>> doesn't mind if I help him plan, and get the right tools and parts in
>>>>> advance.
>>>>>
>>>>> I know this is an old subject, but I really do want to do this
>>>>> upgrade, as I
>>>>> have always felt that this Jeep was very weak in the heater fan
>>>>> output.
>>>>> Doubling the output would help a LOT in the dead of winter.
>>>>>
>>>>> Thanks for helping me on these questions !!!!
>>>>>
>>>>>
>>>>> --james--
>>>>>
>>>>>
>>>>
>>

What's up with the resistor strip? Why do we need it? I thought the three
position blower switch gave the three different voltgaes to the motor. I
just dont understand what the resistor strip does (other than resist)

"Mike Romain" > wrote in message
g.com...
> SnoMan wrote:
>> On Sun, 18 Mar 2007 08:57:25 -0700, "Anthony T" >
>> wrote:
>>
>>> not having the dash off wasn't the problem (I agree it would be easier
>>> if it was off). My problem was the hard plastic duct that runs from the
>>> air intake on the hood down to the heater assumbly. It was this duct
>>> that caused my problems. You are correct though, it's easier to see
>>> what's going on with the dash off.
>>
>>
>> If this is a bigger motor too you need to consider changing the
>> resitor strip that gives you speeds because the stock one may fail in
>> time under the heavier current draw from a bigger motor.
>> -----------------
>> TheSnoMan.com
>
> The are both stock GM items. AMC used a GM heater setup with the same
> resistor pack which is why the larger motor fits right in and to the
> blower cage also.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)

The resisters blow off power as heat and just act like a basic voltage
regulator to slow down the motor.

The motor only has one set of wiring in it so it needs different volts
for different speeds.

Mike

Anthony T wrote:
> What's up with the resistor strip? Why do we need it? I thought the
> three position blower switch gave the three different voltgaes to the
> motor. I just dont understand what the resistor strip does (other than
> resist)
>
> "Mike Romain" > wrote in message
> g.com...
>> SnoMan wrote:
>>> On Sun, 18 Mar 2007 08:57:25 -0700, "Anthony T" >
>>> wrote:
>>>
>>>> not having the dash off wasn't the problem (I agree it would be
>>>> easier if it was off). My problem was the hard plastic duct that
>>>> runs from the air intake on the hood down to the heater assumbly. It
>>>> was this duct that caused my problems. You are correct though, it's
>>>> easier to see what's going on with the dash off.
>>>
>>>
>>> If this is a bigger motor too you need to consider changing the
>>> resitor strip that gives you speeds because the stock one may fail in
>>> time under the heavier current draw from a bigger motor.
>>> -----------------
>>> TheSnoMan.com
>>
>> The are both stock GM items. AMC used a GM heater setup with the same
>> resistor pack which is why the larger motor fits right in and to the
>> blower cage also.
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>> (More Off Road album links at bottom of the view page)
>

The blower switch just routes current through different portions of
the resister for different fan speeds. It's the resister that actually
does the work of varying voltage to the motor.


On Sun, 18 Mar 2007 11:04:09 -0700, "Anthony T" >
wrote:

>What's up with the resistor strip? Why do we need it? I thought the three
>position blower switch gave the three different voltgaes to the motor. I
>just dont understand what the resistor strip does (other than resist)
>
>"Mike Romain" > wrote in message
ng.com...
>> SnoMan wrote:
>>> On Sun, 18 Mar 2007 08:57:25 -0700, "Anthony T" >
>>> wrote:
>>>
>>>> not having the dash off wasn't the problem (I agree it would be easier
>>>> if it was off). My problem was the hard plastic duct that runs from the
>>>> air intake on the hood down to the heater assumbly. It was this duct
>>>> that caused my problems. You are correct though, it's easier to see
>>>> what's going on with the dash off.
>>>
>>>
>>> If this is a bigger motor too you need to consider changing the
>>> resitor strip that gives you speeds because the stock one may fail in
>>> time under the heavier current draw from a bigger motor.
>>> -----------------
>>> TheSnoMan.com
>>
>> The are both stock GM items. AMC used a GM heater setup with the same
>> resistor pack which is why the larger motor fits right in and to the
>> blower cage also.
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>> (More Off Road album links at bottom of the view page)

On Sun, 18 Mar 2007 12:49:16 -0700, bllsht > wrote:

>The blower switch just routes current through different portions of
>the resister for different fan speeds. It's the resister that actually
>does the work of varying voltage to the motor.


True and the voltage and current dropped across them is converted to
heat and airflow in duct keeps them for toasting most of the time.
-----------------
TheSnoMan.com

On Sun, 18 Mar 2007 10:59:06 -0700, "Anthony T" >
wrote:

> After
>about 10 miles down the hi-way...BOOM...it backfired and the entire Jeep
>shook. So I pulled it over and it died. I did re-start the engine and
>after about 30 seconds...BOOM.


Are we talking thru carb or exhuast on this backfire problem because
this narrows down possible causes.
-----------------
TheSnoMan.com

SnoMan,
I'll be honest, I wasn't paying too much attention as my Son was in the back
seat and I just wanted to get off the hi-way after I heard the Bang (I
didn't want to be stuck in the middle of a four lane with a child in the
back seat) I thing it was thru the carb, but not absolutely sure.


"SnoMan" > wrote in message
...
> On Sun, 18 Mar 2007 10:59:06 -0700, "Anthony T" >
> wrote:
>
>> After
>>about 10 miles down the hi-way...BOOM...it backfired and the entire Jeep
>>shook. So I pulled it over and it died. I did re-start the engine and
>>after about 30 seconds...BOOM.
>
>
> Are we talking thru carb or exhuast on this backfire problem because
> this narrows down possible causes.
> -----------------
> TheSnoMan.com

On Sun, 18 Mar 2007 19:51:16 -0700, "Anthony T" >
wrote:

>I'll be honest, I wasn't paying too much attention as my Son was in the back
>seat and I just wanted to get off the hi-way after I heard the Bang (I
>didn't want to be stuck in the middle of a four lane with a child in the
>back seat) I thing it was thru the carb, but not absolutely sure.


When it is through the carb it is usually (not always) from a leaning
out conditon. When mixture gets too lean it does not fire properly and
the mixuture is dumped into exhaust manifold where it starts to ignite
and then the flame travel back into cylinder and into intake during
valve overlap. You may have a weak pump or plugged filter that is
causing it to lean out under high demand periods. I sticking or burnt
valve can cause this to but if it is a burnt valve it would be
consistant. I have also seen a worn cam lobe cause this but it too was
also consistant and predictable.
-----------------
TheSnoMan.com

Bad news !!!!! The shop did a block check ($75) and there is exhaust
getting into the cooling system. Not much, he's getting a hydrocarbon
reading in my radiator/coolant. Mechanic says it's probably not the head
gasket, but rather, a cracked head. That's gonna hurt.

"SnoMan" > wrote in message
...
> On Sun, 18 Mar 2007 19:51:16 -0700, "Anthony T" >
> wrote:
>
>>I'll be honest, I wasn't paying too much attention as my Son was in the
>>back
>>seat and I just wanted to get off the hi-way after I heard the Bang (I
>>didn't want to be stuck in the middle of a four lane with a child in the
>>back seat) I thing it was thru the carb, but not absolutely sure.
>
>
> When it is through the carb it is usually (not always) from a leaning
> out conditon. When mixture gets too lean it does not fire properly and
> the mixuture is dumped into exhaust manifold where it starts to ignite
> and then the flame travel back into cylinder and into intake during
> valve overlap. You may have a weak pump or plugged filter that is
> causing it to lean out under high demand periods. I sticking or burnt
> valve can cause this to but if it is a burnt valve it would be
> consistant. I have also seen a worn cam lobe cause this but it too was
> also consistant and predictable.
> -----------------
> TheSnoMan.com