'63Riv: Heat turns on under acceleration?

[Adambravo]

Here's an odd one: when I'm running the a/c on my '63 and accelerate (usually from a standing start), I get a bit off hot air blowing out of the vents. Any insight...?

[RivNut]

That's pretty typical of lots of cars. A sudden change in vacuum will cause this.

[CTX-SLPR]

I think it has to do with the STV setup since it runs off of manifold vacuum which will drop when you throttle it.

RivNut,

Have you experienced this on any cars with the STV eliminator kits?

[RivNut]

I've never installed one of those kits. The '63 is still under restoration and the '64 will probably get a Vintage Air or Hot Rod Air system.

Ed

[CTX-SLPR]

I'm putting a Sanden on my '64 but it'll keep the STV though I do have the eliminator kit.

[Jim Cannon]

Here's an odd one: when I'm running the a/c on my '63 and accelerate (usually from a standing start), I get a bit off hot air blowing out of the vents. Any insight...?

This is a known problem with the '63 Riv with A/C. There is no vacuum storage bottle on the '63. They added one in later years. When you step on the gas, and you lose engine vacuum (a normal result of opening the throttle) you lose the vacuum that holds all the little flapper doors in the A/C position. (No vacuum applied to the diaphragms gives you heat.)

To minimize it, you need to go through the entire vacuum system and eliminate all, even the smallest, leaks. The more tight you make the system, the longer it will go without losing enough vacuum on acceleration to let the diaphragms move. It's not just the STV that is causing it. It is everything in the system. All those little vacuum valves, hoses, connector nipples, diaphragms, etc.

On my '63, I tightened up everything as best I could. I also added a small black plastic vacuum reservoir from a '64 to my Riv. That totally eliminated the problem.

Take your time with the vacuum system and you can reduce this.

[bb1970]

My '65 has vacuum issues. Heat always coming in. I chased lines. Replaced cracked hoses. Plugged in unplugged lines. It was better. Never resolved. For $12 you can put a manual shut off in a heater hose and block off flow to the heater core. Turn it off in the summer on in the winter.

[1965rivgs]

Your `63 should have a vacuum check valve at the intake manifold. If it is inop add another inline valve and your problem should go away.

Tom Mooney.

[Guest u571]

Jim,Im curious,is the vacuum storage tank you added that small round tank? and which lines did you connect to it?

Mark

[Jim Cannon]

Yes, it's the round one.

One port has a check valve on it that allows you to suck some air out of the port but not blow any in. Connect that to the engine where the original vacuum hose is connected. Move the original hose over to the storage bottle.

The check valve in the storage bottle helps overcome any loss at the check valve in the manifold, in case it is leaking (as Tom mentions).

Jim