SECOND in a series of CJ-5 defroster problem solving tips!!!

If my first post caught your intrest, read on! After removing the coolant soaked MICE NESTS that were built up against the heater core(these were substantial!) I removed the components from the heater box & cleaned out the synthetic heater box in my slop sink with comet brand powder detergent followed by a clorox bleach wash & final water winse. "MICE RICE" can be VERY toxic to the lungs so if you find it in your heater box clean it out well & DISINFECT!
After the cleaning process of the synthetic heater box I took the FRESH air plate & rod plus the BLENDING plate & rod & the sheet metal plates from the back of the heater box & bead blasted them in my bead blasting box. This was followed by three coats of aluminum paint sprayed on them out of a rattle can to prevent rust. You can get the aluminum colored can of spray paint at Wally World where I live at for 99 cents.
My next step was to go to Ace hardware & purcase some 1/8th diameter pop rivits in both 1/8th & 1/4 inch grip range plus washers for them as well as a one by two foot piece of ALUMINUM screen door mesh. I cut the ALUMINUM mesh to fit EACH & EVERY penetration leading into & out of the heater box save the core inlet/outlet penetrations. This includes both the round penetration that allows air to be sucked into the fan chamber from the core chamber as well as the oval fresh air penetration, the heater outlet penetrations as well as the two defroster penetrations. Aluminum mesh is more easily worked with than steel mesh screen & MICE can't knaw thru it. Avoid synthetic mesh as mice chew right thru it!
While the installation of the wire mesh is both time consuming/frustrating it's WELL WORTH IT! I live on a farm & I'm, telling you threre's gotta be a hundred forty eleven field mice per acre!!! This stopped em cold! Wish I had taken digitals of this complete project as I went along so I could share them. It's easy to do tho if your gifted with common sence & have patience. Ask anytime thru the series if ya have questions.
In the next post I will describe how i MODIFIED the ALL IMPORTANT BLENDING PLATE FOR A NEXT TO AIRTIGHT SEAL. This REALLY MADE A DIFFERENCE IN THE DEFROSTER OUTPUT !!!

 

Well, hurry up! We're actually having some cold weather here, and I'm getting tired of scraping the outside of the windshield, then scraping the inside so I can see!R)
(Ok, maybe not the -1* like you're having!)

 

Mike, I actually had the third post done but lost it to cyber space, it was a long one post too! I'll be posting #three in a hour or so. Keep a look out for the series as you'll like it!
Bob aka: slow bear!

 

Third in a series of CJ-5 defroster solving tips!!!

This is my second attempt at sending the third part in the series. Sorry for the "hiatus" but cyber space ate the first attempt to post # three.
This part has to do with the ALL IMPORTANT blending plate. Before I start, I must remind those who have read post # two in the series that the aluminum mesh described was installed on the inside of the synthetic heater box, NOT on the out side of the heater box.
The blending plate problem is really difficult to observe with out the sheet metal backing plate removed. Once the sheet metal backing plate is removed how in the heck do you position the blending plate rod in it's proper position to measure for modifications with out putting the sheet metal backing plate back(can't see then!) on so the blending plate rod can be inserted thru the penetration in the sheet metal for alignment?
Answer...vernier caliper! READ THIS PART VERY CAREFULLY OR THE MODIFICATION WILL BE COMPLETLY INEFECTIVE!!! After the box is cleaned reinstall the blending plate/rod plus the two metal spacers, one on each side of the blending plate. With the sheet metal cover installed & secured with a couple screws you will notice the blending plate ROD protruding out thru the sheet metal a quarter of an inch or so.
NOTE; you don't need a high budget vernier caliper for this operation, I meen were not measuring crankshaft journals here! I used a Hempe brand plastic twelve dollar special & it worked fine!!
Place the NARROW end of the vernier caliper(the end that the metal rod protrudes out of for depth measurments) directly bottom dead center BELOW the protruding blending plate rod. The narrow end of the vervier caliper should be resting on the BOTTOM shoulder of the synthetic heater box. Open up the caliper with the knurled wheel UNTIL THE TIP OF THE VERNIER CALIPER MEASURING ROD TOUCHES THE BOTTOM OF THE PROTRUDING BLENDING PLATE ROD. The vernier caliper may have to be shifted slightly left or right for the tip of the vernier caliper measuring rod to align dead center under the protruding blending plate rod.
Once this is acheived mark carefully the position of the vernier caliper on the synthetic heater box with a HIGH visability marking pen & your reference point for plate modifications are secured! Then simply LOCK the vernier caliper in position by turning the knurled set/lock screw & do NOT change the vernier caliper setting UNTIL after the modification's are COMPLETELY thru.
Now remove the sheet metal cover, reposition the vernier caliper to it's MARKED reference position on the bottom shoulder of the synthetic neater box & align the blending plate rod directly on to the top of the vernier caliper measuring rod. Then move the blending plate to the full defrost position & start laughing!!! This does not take an Oppenheimer, Einstein or Steven Hawkings to see the problem!!!!!!!
I'm sure the engineer had designed the plate to offer a COMPROMISE of both heater/defroster at the same time, & with the best of intentions. This "COMPROMISE" has caused us CJ-5er's nothing but rage, confusion, headaches, humiliation, bewilderment, money, rain forest cabin atmosphere, fogging windsheilds & warp ten senile attacks!!!
Unless I have a "one of a kind" blending plate, & from the complaints I have read from other members I don't, this IS THE MAJOR PROBLEM that I can see at this junction into the pre 1976 CJ-5 defroster problem. Who knows, maybe the post 75' CJ-5 owners get tortured just as bad?
In my next post, #4, I'll quide you thru the ACTUAL PLATE MODIFICATION & the goodies, measurements to direct all that squirrel cage air into the defroster duct(s)!

 

Doncha just hate it when the cyberspace eats your work!?!R)
Actually, Spokane is my home town, so I'm feelin' kinda at home with the weather we're having over here.

 

Can't blame ya for the move to the coast Mike, milder climate & a LOT more money to be made! Getting ready to draft the 4th & all critical post. I imagine your 73' has the same heater box as my 75' "Levi" edition J-5!
If you do pull/disassemble the heater box let me know if the blending plate is the same as I described I have in my heater.
Bob.

 

FOURTH in a series of CJ-5 defroster problem solving tips!!!

If you have followed my recommendations/instructions thru my third post you have found out what I found out. The blending plate design is completly bogus. Just a quick visual when the blending plate is in defrost position with the sheet metal cover removed & the blending plate rod resting on top of the vernier caliper rod illustrates this all to clearly!
The end of the blending plate that faces the passenger side of the heater box ACTUALLY has the sheet metal ANGLED UPWARDS! This causes not only a restriction to the forced air entering the upper defrost chamber IT ACTUALLY IS DESIGNED TO DIRECT A FAIR AMOUNT OF FORCED AIR INTO THE LOWER HEATER CHAMBER!!!
You will also notice that the end of the plate towards the drivers side of the heater box is also angled upwards AS IT SHOULD BE. What SHOULD'NT be tho, is the angled piece of sheet metal blending plate does not touch the ceiling of the synthetic heater box. Look closly at this! The end of the blending plate that is at the CORNER of the synthetic ceiling/wall material junction sports a gap between the ceiling/plate of approximately three sixteenth's of an inch.
If this is'nt bad enough the gap inreases to nearly an INCH at the corner of the heater box where the blending plate is SUPPOSED to meet the sheet metal blending chamber cover/synthetic heater box ceiling. I meen what forced air does arrive in the defrost chamber JUST SAILS over the plate & out the other end of the defrost chamber!!! There's NO way the forced air can be directed into either one of the defrost exit penetrations located in the ceiling of the defrost chamber. The forced air just sails over the plate, goes down to meet the other forced air in the lower heater chamber & it all exits down by the floor boards!!!!
The cure is ridiculously SIMPLE & CHEAP in cost, but some what time consuming depending on your modification skills & PATIENCE! The upwards angled sheet metal on the passenger side/end of the plate needs to be put onto a vise & bent DOWNWARDS to meet as closly as possable to the floor of the heater box. This will take some measuring & a "good" eye, or as we used to call it in shooting competition, "Kentucky" windage!
When finished with this step, assemble the blending plate/rod into the box then tighten down the screw that secures the blending plate to the rod & position the vernier caliper on to it's pre marked position on the heater box. Simply place the tip of the blending rod onto the tip of the vernier caliper depth rod & position the blending plate into FULL DEFROST POSITION. This is of course the exact position the blending plate will be in when the blending box sheet metal is installed for the finished project.
NOTE; before you do this step to check for fit, take the TWO METAL WASHERS/SPACERS THAT WERE LOCATED ON THE BLENDING ROD & PUT THEM IN YOUR NUTS & BLOT CABINET AS THEY ARE NO LONGER NEEDED AS WILL BE EXPLAINED LATER!!!
The now modified blending plate does NOT have to fit PERFECTLY to the floor of the heater box when positioned as descibed above but should be CLOSE & some what LEVEL to the heater box floor. In the next step of the series, part five, I will describe the modification of the other end of the blending plate & it's oddities. PATIENCE is the key here gentleman so don't get frustrated or in a hurry here. I envisioned about four five hours of SURGURY inside the heater box once I diagnosed the problem.
In reality it took me six nights after work, dedication, hope & prayer, a keen eye, imagination & "VENTING" irritation by throwing several "senile fits". I meen once over fifty, I found my patience can be "tested" much more easily & this defroster night mare tested me to the limits! I meen JUST getting the forced air directed with abundent velocity INTO the defrost penetration(s) was/is an engineering marvel!!!
I'll post #5 in the series as soon as time allows so keep your eyes open!

 

Re: FOURTH in a series of CJ-5 defroster problem solving tips!!!

Did you take any pics of the process?

 

Re: FOURTH in a series of CJ-5 defroster problem solving tips!!!

I really like the info! I too would like to see pics of the process you descibe!

Kent

 

Will do. If I remember, I'll take pics as I go through it.
Thanks for the great series.

 

Hey slow bear, sounds like you need some barn cats! I usually keep my jeep out in a barn in Deer Park but load it with decon, have not had a problem yet. I just worked my heater over this fall, cables, plastic defrost duct, and it made a huge difference! We will have to go jeeping sometime, I know a great place close to you. PM me. Sounds like you are having a good time.

 

Gpin, Overtime got me bad so had to delay the continuing series, am writing another part this morning. Gpin, the plastic defroster duct/plenum, do you remember what diameter the INLET penetration is? My fiberboard duct/plenum is still a MAJOR restriction to the airflow from the TWO INCH aluminum flex duct I am using between the defroster penetration & duct/plenum. When time allows lets meet so I can get a look at the plastic duct/plenum in your 74'. I'm hell bent on having a "windstorm" for defrosters! Write soon, & thanks Gpin!
Bob.

 

Re: FOURTH in a series of CJ-5 defroster problem solving tips!!!

Kent, I did the heater box modification BEFORE I came across this forum. I feel like a dummy, taking pictures would SO simplify the how to do the process. I'd pull it out & shoot digitals for the troops but I'm using the J-5 at present. Keep reading as there's more posts coming as time allows.
Kent, once your inside the heater box AFTER reading the series I'm posting, you'll be able to do the modifications just on common sence. The marking & positioning of the vernier caliper is the ONLY real critical step to be exact on. You will need to reposition the calipers several times as you make adjustments to get the defroster chamber "leak proof as possable. Read on!
Bob.

 

Re: FOURTH in a series of CJ-5 defroster problem solving tips!!!

Sure wish I had! I never thought of sharing the info & did the modification before I stumbled across this forum. I'll NEVER do something like this again with out digitals to share with others in need. I'm posting #5 in the series shortly, ask if you have any questions, I'll do my best to respond/help.
Bob.

 

FIFTH in a series of CJ-5 defroster problem solving tips!!!

Sure wish I'd taken digitals of this modification for ya guys. After reading this series & your inside your heater box I think you all will find the modifications as I have described them fairly self explanatory. Most who read this will, I would guess, be "reasonably" mechanically inclined. I meen just looking inside the heater box with the metal cover of the back of it & the blending rod resting on the calipers as previously descibed, WILL TELL YOU THE WHOLE STORY!!!
Now, I got the cart ahead of the horse in the last post, few things I forgot to put in for you. The end of the blending plate closest to the passenger side, like the other end of the blending plate shares the same PROGRESSIVE gap problem. I beleive the gap between the blending plate & FLOOR of the heater box is APPROXIMATLY five eights of an inch at the corner of the plate closest to the fire wall. You need to position your PRESET vernier caliper on the mark mentioned earlier, position the blending plate rod on top of the vernier's depth rod & position the blending plate in full defrost position, THEN take the measurement between the heater box floor & the bottom of the plate AT THE BEND/ANGLE IN THE BLENDING PLATE.
The other side of the blending plate should be almost touching the floor of the heater box as mine was. Once the distance of the gap is measured & RECORDED, remove the blending plate from the blending plate rod. Place the blending plate in a bench vise of suitable size & CAREFULLY straigten out the end of the plate that is closest to the passenger side of the heater box. DO NOT touch the other end of the blending plate that is closest to the defroster penetrations, yet!
Once the passenger side of the blending plate is staightened out to the best of your ability, you need to take the recorded gap measurement & mark it on TOP of the plate. Make SURE that the blending plate has it's top surface FACING you. Measuring from the bottom edge of the blending plate place a mark the recorded distance of the gap on the edge of the plate closest to the fire wall. Then simply use a straight edge to draw a line from that mark to the other corner of the blending plate. This is the line you will need to align with the top part of the vise's jaws.
Cinch the vise down TIGHT on the line & carefully bend the blending plate until the angle of the "TAIL" of the blending plate aligns "closly" with the bottom of the heater box. This may take several "attempts" to get it to your satisfaction. Once completed, you have taken the first step in "debugging" the pre 76'J-5 defroster curse!
Note; insalling, removal of the blending plate from the blending plate rod will most likly need to be done several times for proper "visual" fit of the blending plate to heater box surface. Insalling/removal of this plate caused me to throw my first "senile" attack on the project, I meen I was fit to be tied & steaming! Play it smart & get a mini pry bar. They look like a screw driver except the "business" end is of a pry bar configuration complete with a little vee nothched in it for finish nail removal etc.
This really HELPS sence for "fitting" purposes regarding the blending plate the plate/rod screw needs to be tightened EACH time. Trying to get the plate of the rod with out the little pry bar may produce a bad attitude, foul language & excessive alcohol consumption!
I'm not a journalist hence forth my posts may get a "little" redundency in them. With out digitals the "written word" is the best I can do so just trying to explain what I've done to the best of my abilities, to make it easier on those who wish to follow my heater box modifications.
Post # six will explain my modification to the other end of the blending plate. With these two modifications the hard part is pretty much over, regarding the heater box! If you follow my series, you can have a "balanced & blueprinted" J-5 heater/defroster box second to none!









from the needs to be bent back straight before bending it downwards in the direction of the heater box floor. I did this process in my bench vise. BENT AT AN ANGLE. If memory serves me correctly

 

Re: FIFTH in a series of CJ-5 defroster problem solving tips!!!

Umm, Slow Bear, is there something missing from the area that is blank? The first part of the last sentence is cut off, too.:?

 

The plastic defrost duct is just a reproduction of the paper duct, just in plastic. I bought it from 4wheeldrive hardware. I believe it has the same size inlet as the orginal. My old paper one had so many holes all it did was warm my dash board and fog my windshield, I now can actually here/feel the air coming out. Yes it would be nice if you could hook up both outlets from the heater box to the defrost duct. I took a paint can cap and plugged the one outlet next to the defrost duct outlet to give the defrost a little more pressure. Maybe you should build a dual inlet defrost duct in your series. Take pics!

 

I actually am tryiing to use both outlets for increased air VOLUME. This will be covered in the series later. Any future modifications I do will CERTAINLY have a bevy of digitals to help fellow forumist simlify the project.

 

Re: FIFTH in a series of CJ-5 defroster problem solving tips!!!

Lost Dawg, that last part was suppossed to be deleted. I'll bring that up in the next post. Thanks!
Slow Bear.

 

Sixth in a series of CJ-5 defroster problem solving tips!!!

The last sentence of post # five at the bottom of the page was supposed to be deleted, so discard it.
When the modification is completed to the "entrance ramp" of the blending plate as described in post # five, you will notice the blending plate now has a stream lined approach for forced air from the fan compartment to navigate up the top side of the blending plate right up to the next problem.
If your heater box is like mine you will find a progressive gap across the angled "exit ramp" from about 1/8th of an inch to about one inch at the edge of the blending plate closest to the fire wall. This gap between the edge of the blending plate exit ramp & the interior of the defrost chamber ceiling is as critical regarding the finished fit as the before described entrance ramp.
After carefully measuring this gap between your blending plate edge/defroster ceiling, cut a piece of sheet metal that will fill the gap with enough "tail" left to securly pop rivit it onto the existing defrost exit ramp. I found an "interference" fit here, between the edge of the now extended exit ramp & the wall of the synthetic heater box when moving the blending plate from defrost to heater position.
This was cured by bending the MODIFIED part of the exit ramp BACK towards the drivers side edge of the first defroster penetration located in the ceiling. When all finished, assemble the blending plate assembly WITH the sheet metal blending plate cover installed & tightened down. Operation of the blending plate from defrost to heater & visa versa should not encounter any "snags". If it does you will need to bend the modified part of the exit ramp ever closer to the first defrost penetration until cleared. There will be some "rattling side to side as the spacers were discarde as mentioned in a previous post.
Finally, trim of "about" three sixteenths of sheet metal off the modified exit ramp so once again there is a gap spanning between the modified exit ramp edge & the interior of the defrost chamber ceiling. This is for installation of a tubular vinyl gasket that will make your defrost chamber"leak proof".
In the next post I will describe the LAST step in modifications that will direct ALL forced air into the defrost penetration(s). When I get humiliated as bad as my J-5's defrosters have humiliated me I go all out! I meen my defrost chamber is not only leak proof it's pretty near hermetically sealed!!!
My perseverence/patience have paid off tho, big time! My defrost chamber is so leak proof that the squirrel cage can not force the air out of ONE defrost penetration as fast as it is forcing air into the defrost chamber ! This meens I can plumb two defrost ducts/plenums into the windsheild frame & still create a wind storm in the cabin, & thats EXACTLY where this ole cowboy's a headin!
Stay tuned!!!