Simple Heater Valve Solution for Early Cars (And Late)

I believe I found a simple solution for the early cars heater valve. The LS engines require an H valve, and the only H valves I have found are for a vacuum operated system. Rather than rigging up something to convert the H valve, I found the following heater valve from a 2000 Pontiac Grand Am. It's a bypass that opens when the pressure increases. The inlets and outlets are both 3/4. The LS return is 5/8, so I had to stretch that hose a bit to get it on the 3/4 fitting... Hoping it doesn't stress it too much. Then I plumbed in the stock early heater blockoff valve. This would work for late cars too, but I don't think it's any easier than just installing an H valve.

[You must be registered and logged in to see this link.]


[You must be registered and logged in to see this image.]

Is there any way to actually control the valve? It seems like it would just open when the system got up to pressure.

this valve is just a bypass, you would still need the 944 heater control valve in the system.

Exactly. This valve is just a bypass that operates alongside your stock 944 heater valve. That's the advantage for us early car folks, since we have a cable operated heater valve.

So does it automatically route back to the engine if you have the stock heater valve closed?

My problem is I don't have enough room to use the stock one. I modified a vacuum-actuated valve to use the cable, but I'm having trouble finding a cable long enough to reach. I used one that was meant to be a throttle cable for a small engine, but it corroded after a single season, so right now I have to open my hood to change my heat setting.

Yeah, if you block flow to the heater with your stock 944 valve, this will open. My 944 heater valve is plumbed in with a longer cable, I didn't make it fit with the stock cable. Maybe there is some kind of a hose you can put over the metal shielding for the cable? I also just bought a cable, hoping it doesn't rust out. Maybe a vacuum line over the steel would help, could oil it up then?

Another option:
[You must be registered and logged in to see this image.]


I used this and located it just above the LS heater outlets.  I extended the cable control, and Done!

Also, I cut the large mount of it, and it made it quite a bit smaller.

Gord.

What did you use to extend the cable?