Heater Water Cock - Valve Relocation Project

[Captain Obvious]

The heater in my 77 always blew hot regardless of where I put the temperature slider and I tracked the problem down to a faulty water **** valve under the dash. I had the capillary style valve (http://www.classiczcars.com/forums/thread46448.html) and spent a little time looking into a direct replacement, but after spending that kind of "quality time" working under the dash, I decided that I never wanted to go through that again. So I changed over to a ubiquitous newer style water control valve which I relocated up in the engine compartment instead of under the dash.

I grabbed a bunch of different valves from the junkyard from various Honda and Toyota products, trying to find one that had the correct flow direction, had the lever on the proper side, and opened when the cable "pushed" instead of "pulled". I kinda lost track of which was which, but I believe the one I finally used was from a 2000 Acura TL.

Here's the valve I used. Flow direction is left to right when lever is on the side pictured, and it's CW to open again with lever as pictured. That means I can mount it on the return line from the heater core and it's push to open. Note that I also had to make a new control arm for the valve to get the ratios correct between between the travel distance of the control slider and the travel distance of the new valve:

Here's a couple pics of the mounting bracket I made for the valve:

Here's the whole thing painted, mounted, and plumbed in the engine compartment. I attached it to the mounting bracket for the brake lines and fed the control cable through an existing hole in the firewall. I believe this hole is where the vacuum line goes for the HVAC system on cars with A/C. The hole location was a little higher than optimum, but since I don't have A/C, this hole was unused which saved me the trouble of drilling a new hole only to find out that the whole project was a mistake:

It wasn't a mistake! It works great and will be a breeze to work on in the future if necessary. One other bonus is how simple it is under the dash without the valve and all the associated hoses:

[jonathanrussell]

This is really quite ingenious. Thanks for sharing.

[Zed Head]

It does look pretty cool.

I assume that the other end of the cable is attached to the heater control lever in the AC control panel. How does the throw at the panel match the throw at the valve? And have you tried it yet? Do you have a cooler cabin now?

[Captain Obvious]

Yup, I tried it and it works perfect! Heater core is completely cool with the lever all the way to cold, and as hot as it used to be when in the hot position. Much cooler cabin!

Cooler cabin

Simpler and cheap generic under dash hoses

Easy future heater core replacement

Easy future valve replacement

Cheap ubiquitous valve

About the cable throw at the panel vs. the throw at the valve... Originally, the cable movement length at the panel was a little bit longer than the max throw at the valve. So in order to take care of that, I made a new longer arm for the valve. The longer arm takes more linear motion to go between endpoints, and as a bonus, the force required to move it is less. I don't have a pic handy of the original arm vs. my longer one, but I'm thinking that the one I made is maybe half inch longer than the original.

All in all, I'm happy with the way this turned out. I'm not 100% thrilled with the hose or cable routing in the engine compartment, but one of the big reasons I put stuff where I did is because I didn't want to cut any additional holes in the firewall and I wanted to make the whole thing reversible if necessary. If I knew it would work, I guess I would have been willing to make it more permanent right off the bat, but since I was making this up as I went along, I wasn't sure how it would turn out.

If I were starting with a clean slate, I would try to move the valve down and towards the battery a little, but in order to do that you would have to cut a new hole for the cable as the stock hole is too far up the wall.

[Mikes Z car]

Thanks for the write up and the great pictures.

[Captain Obvious]

Reloaded pics:

The heater in my 77 always blew hot regardless of where I put the temperature slider and I tracked the problem down to a faulty water cokk valve under the dash. I had the capillary style valve (http://www.classiczcars.com/forums/thread46448.html) and spent a little time looking into a direct replacement, but after spending that kind of "quality time" working under the dash, I decided that I never wanted to go through that again. So I changed over to a ubiquitous newer style water control valve which I relocated up in the engine compartment instead of under the dash.

I grabbed a bunch of different valves from the junkyard from various Honda and Toyota products, trying to find one that had the correct flow direction, had the lever on the proper side, and opened when the cable "pushed" instead of "pulled". I kinda lost track of which was which, but I believe the one I finally used was from a 2000 Acura TL.

Here's the valve I used. Flow direction is left to right when lever is on the side pictured, and it's CW to open again with lever as pictured. That means I can mount it on the return line from the heater core and it's push to open. Note that I also had to make a new control arm for the valve to get the ratios correct between between the travel distance of the control slider and the travel distance of the new valve:

I'm sure there are much simpler ways to mount a valve and connect to it but here's what I did. I made a mounting bracket for the valve which also included the provision for attaching the cable control:

Here's the whole thing painted, mounted, and plumbed in the engine compartment. I attached it to the mounting bracket for the brake lines and fed the control cable through an existing hole in the firewall. I believe this hole is where the vacuum line goes for the HVAC system on cars with A/C. The hole location was a little higher than optimum, but since I don't have A/C, this hole was unused which saved me the trouble of drilling a new hole only to find out that the whole project was a mistake:

It wasn't a mistake! It works great and will be a breeze to work on in the future if necessary.

[HusseinHolland]

I'm going to have to work on the HVAC in my newly acquired 75 280Z - the PO said the core leaks. I'm reviewing your Escort core mod for that (so far the pics are all dead, but only on page 2). As far as this mod goes, you don't mention the heater control cable, does that mean you used the stock cable & re-routed it out the firewall?

I do like the idea of the valve being out of the dash area.

[siteunseen]

I thought my 240's core was bad when I bought the car but after pressure testing it with positive air or my shop-vac sucking negative pressure I realized it was okay. The flow valve was where all the leaking was coming from. Check the core somehow before you buy another one. It may be the same situation I had, still a tough job but nowhere near as much as replacing the heater core. I suggest taking the passenger's seat out and put a couch cushion over the door sill and use 1/4" drive sockets.

Edited March 20, 2023 by siteunseen

[SteveJ]

Not specific to @HusseinHolland's question, but the valve used by @Captain Obviousdoes appear to be from a 2000 Acura TL. https://www.rockauto.com/en/moreinfo.php?pk=6636476&cc=1361090&pt=6860

As for the dead photos, blame Photobucket. Now @Mike generously hosts more photos on the server so we can include images that aren't dependent upon outside services.

[HusseinHolland]

I'm going to keep the heater valve in the cabin - I want to convert to AN bulkhead fittings for the bayside hoses. In part so that when I do the drivetrain conversion (at some future date) it will be easier to modify, same as the AC line fittings

I'm going to get rid of the long flapping hose & put a section of 5/8 SS pipe (approx 18") which will be bolted to the block in the existing harness attachment points. I'll be bead -rolling the pipe for a tight hose fit

Edited May 4, 2023 by HusseinHolland