Defrost On 1975 Cj5

Hi Guy's, another thing to improve, i have problem with the defrost last week-end. I know weather condition were a little extreme around here. Last week-end we had a ready bad snow storm along a -22 degree outside. Decided to go in town (maybe a 15 miles trip) and i had a really hard time defrosting the windsheild. I don't have the stock heater, i replaced it with a vintage air gen II couple of year's back.

https://www.summitracing.com/int/parts/vta-506101/overview/

I've been searching over google for any mod that other as done but i only find information on the blazer motor on the 76+ models.

Since i swap out the wintage air i didn't find any big improve over the oem system, Also i cannot find info on cfm or btu for this particular product. I'm able to get a summit heater (260 cfm with 28 000 btu) but since we are losing a lot of cfm in the open windsheild i'm looking forward other sollution to improve defrost.

https://www.summitracing.com/int/parts/sum-991102-1/overview/

 

Why don't you contact Vintage Air ( Home - Vintage Air ) and request the BTU and CFM spec's for the heater. With that information you can compare your heater to the others you are considering.

Also, was the engine fully up to operating temperature? You said it was -22 degrees outside during your trip to town.

 

If I were going to drive in -22 F or C, I would go for the 40K btu heater from summit. https://www.summitracing.com/nv/parts/sum-991106/overview/?rrec=true
This heater has two motors and 3 ports. One port to the defrost, reduce the other two ports to 1" dia and run one hose up your jacket. The other to your passenger........

 

Did send an email this morning so i can have the right information.

Yes engine was going around 180-200, i have electric fan with controler so temp is just right is suppose to be.

I found people who were able to put a sheet metal along with silicone to block off the end of windsheild frame just past the wiper linkage. It should help keeping air flow only on the bottom part and not all around the windsheild and is numberus hole.

 

DO I understand well? this summit racing is connected to the engine water and get the heat from the water in the engine?

 

yes i just found this product too....it has only one motor but two squirell cage. 40 000 btu and 300 cfm should make a huge difference. but as 45es stated, i need to know what cfm i have right know. But it will be definitly a big upgrade since i wasnt very excited when i receive the vintage air unit.

Since jeep cj has two hole on the windsheild for the defrost i could get away with the " Y " pipe and run two hoze from the heater and the third one for cabin heating.

 

yes, summit and the vintage air use the oem water hoze for the heater.

 

I think that is an up-hill battle first and foremost created by the -22C or / -7.6 F ??...........in either case those are tough conditions to get a windshield or the cab of a Tin Can CJ to warm up effectively to defrost the windshield or for that matter the folks inside.

Air Leakage is the big enemy as you have already figured out.........and so starting with larger CFM numbers is at least a move in the right direction......but there would also be a need in extreme temperatures to have all the venting insulated in some form just to get air to the cold glass above a temperature that would help in the defrost need...........

Yes that large cavity within the windshield frame where the vents reside is a big Minus as that metal on one side is constantly seeing ambient or your -22C.

Perhaps a small additional 12v heater / blower used only during the extremes ?............some possible fixes here: Best Portable Car Heaters | How to Heat a Car in Winter | Buyer’s Guide & Investigation of Electric, Propane and Diesel Devices in 2019

take it off put it on , plug it in.............?

 

-22f or -30c running the jeep at 30 mph in a 12" of snow....that was maybe a little too much for the Cj.

But i was never satisfied with the air flow since i took it out of the box. The fact that i was able to direct the air where i want with a knob was very appeling when i did bought the vintage air. But the first problem will be here.

 

My Prototype heater fix for a CJ using the Summit heater as a base.....blows plenty of air to the defrost and also keeps the legs and body happy... Aluminum is probably not the right material as it heat sinks the cold........Plastic would be a better material for the Plenum ....but that's another project!

 

I would say aluminum is fine since it's all inside the cabin. Any heat lost to radiation of the aluminum goes to the cabin air and raises the temp of the surroundings. Warming the surroundings reduces the heat loss to the surroundings from the heated air. It would be better to have that heat in the air sent toward you, but I expect the difference will be very small. You might worry about burns if you touch box while the heat is blasting ... maybe. Likely it will feel hot and not be hot enough to burn without lengthy contact; you'll reflexively pull away first.

 

you forgot the most interesting part



Love the adapter for the winsheid. As i am always overkill i would look over the bigger one that summit offer the one a 40 000 btu and 300 cfm along his 3 outlet

As alweay this forum is great for the idea you guy's bring.

thank

 

Ok just got an answer from Vintage....CfM isnt so bad but btu.....i think i got a good part of the problem....

224 blower CFM

3,000-5,000K BTU


Summit heater the one i'm looking at are rater 260 or 300 cfm and 28 000 or 40 000 btu


Number speak by themselve....

 

Yep , but nothings easy!

 

As for cabin...not so much but i was all dress to beat down the winter so it wasnt so bad....biggest issue is the defrost....but as other stated i was in the worst condition i ever seen.

 

I have the 28,000 btu heater. One port running to the windshield and the other runs to a vent under the dash. The coldest I operate in is about 30 F. Whenever I know I am going in the cold, I pull the floor mats out so the heat from the mufflers, right under my feet, warms the jeep as well. We are about to put a heater in steves's 71 project; he is going with the 40,000 btu heater as he will be taking his kids along quite a bit.
I wouldn't consider anything less than the 40K unit.

 

Yeah i took some mesurement yesterday and the 40 000 btu should fit right there. Plan to use two outler for defrost and one for ambiant air.