Heater core - keeping it cozy

Panteras competing in the early days had to run cut-off heater flow valves because of the number of failures and injuries to drivers from rupturing that little 3" heater hose under the dash. High rpms on overage hoses were the cause. Passengers have been injured as well depending on how the hose blew.  Some owners didn't even realize there was a breakable hose down there.

We had to use TWO VISIBLE manual valves when competing  because Tech Inspectors had no time to have you pull the firewall door and trace out the plumbing to be sure the valve(s) actually cut off the heater feed. Sure, one valve would theoretically be enough but again, Inspectors were often not Pantera owners. So electric valves were illegal and thus very uncommon.

Good idea. Fresh air is nice if/when the A/C goes out. Early '71 and later '74s had a stock fresh air option with different controls, routed thru the heater boxes. I ran two such cowl holes to big 90 degree copper fittings with home-made throttle valves aimed at the seats (no hoses needed). They were very effective crossing the Mojave desert, as my A/C never made it to and from 'Vegas while operating! Cracking a window makes conversation impossible over 100 mph.

My car has the shut off valves, so normally there is no hot water to the heater core at all. Last January, I had to drive the car on a 28 degree day in light snow. I drove for about 40 minutes and the cabin was comfortably warm. I didn't have to defrost, though, so I might have needed the heater for that, but for simple driving, I see a functioning heater as a pretty low priority.

On my drive yesterday back from Orange CA (all of Southern California!) I drove in hail and rain!! I want all that stuff to work being my daily driver!
I may sound like a wimp but I had enough of that BS when I was living (in Northern California in the foothills,) in my 1974 Pontiac Safari Station Wagon when I came to the States in winter 1995!  I paid my dues!

The major advantage to a valve such as that is, when it’s turned off, no hoses or heater related parts, inside the passenger compartment, are under pressure (positive or negative). It makes shut-off valves redundant and unnecessary.

I am replacing the 3 cables right now for hot and cold… Defrost and so on.. those levers have two holes in them for the cable to hook in! The one closest to the part you push on are used for the on off valve, and it works perfectly to shut it off all the way and open it all the way! The other two go in the other hole, closer to the pivot point! at least for the shut off valve I’m using It works

Received my bypass well today!

My uneducated guess would be it’s better having it still circulating, versus just shutting both pipes off with the Home Depot ball valves…

Installed heater box with new foam seals and new control cables

The upgrade

and another addition: outside air …

that connects to the void under the grill but to the right of the opening so it can’t rain in .. 1” standpipe in work…

New A/C hoses.. clean… the whole system has O-rings… no more flared fittings!

Looking good.

I just finished the same project this weekend.  I don't like the final location of the hoses in the engine bay, so I plan to go at that again when I get time.  Need to add some tension relief on the hoses too.

Also going to hide the wiring when I get time.

First 95F day in PHX so I should be able to test my cooling system and AC while I sit in bumper-to-bumper traffic on the 101, on the way to the monthly Pantera dinner.

John

I left my hoses exposed… detracts from the ugly undercoating.. 😂🤣

also made new ground connections left and right for the tail lights!

Connection flanges for the outside air to the fan..

stand off reaching inside the void under the wiper grill

fan flange slightly offset to clear A/C lines

the 3M windshield glue dried over the weekend nicely-flanges are solid!

The finished fresh air project:

keep leaves and debris out, prefect snug fit but it can still remove it from the inside to clean, O-ring secures it in place!

BUT: how do I clean this area out?

and everything (expansion valve) sealed and insulated!

The theory is that about 25% (4 fan sections in total, one of them fed solely by the hose) of the air moved by the fan is fresh outside air which can be directed with the heater controls to the windshield or down or whatever the flaps are set! Or 100% of whatever air is pushed by the driving speed thru the grill under the windshield with the fan off…

we will see…🤓

A/C got checked for leaks… and passed!

charged now! Success….
mind you… it’s all converted to O-rings - no more flares!! It should last ….

Installed electric shutoff valve..

Nice work!

Now it only has to work nicely..