Vacuum solenoid question

[Silk]

I have a vacuum solenoid that activates my heater valve. The solenoid usually won't activate unless I'm at idle, and then once it does and the heater's on, it'll shut off if I hit the gas really hard (a rare occurance, of course). Is this just normal due to vacuum loss under acceleration, or does it sound like I have a vacuum leak?

[Cobra20646]

Hey Gary,
Sounds like a normal thing if your running any kind of cam with more than stock overlap. You can add a vacuum canister to "store" vacuum while under acceleration. Check with Cobra Ed, he had a similar problem with his power brakes and I think he went to a canister..... but I'm not sure.
I had a similar condition with another car and just learned to live with it ... either that or I was just too lazy to do anything with with it
- Jim -

[Aussie Mike]

I got rid of the vacum operated valve and just put in an inline tap. I turn it on in Winter and off in Summer. The valve just seemed to be one more possible thing to fail and another possible airleak.

Cheers

[Silk]

Aussie - A tap sounds like a good ultimate solution if this on-and-off business proves too much of a hassle. Thanks.

Jim - My cam isn't too radical, but it does have more than stock overlap. I'll check in with Ed on the canister idea. In any event, I think I'd rather have my heater cut out when accelerating rather than my brakes. By the way, have you started your wiring project yet? Hope not, since it's supposed to be in the mid-70s today. BTW, Wade was talking about a Polar Bear run in Dec. or Jan. on a suitably cold weekend - no tops allowed. So don't take too long with the wiring!

[CobraEd]

I was going to go with the cannister but never got around to it. I just turned up the idle a little instead. AussieMike has a good idea though. Just put a manual valve in it, or break oen the vacume part of the valve and clamp it open in winter and closed in summer. Or attach it to an old fassioned choke cable and make it dash controlled. This gives you good temp control while providing one more gizmo on the dash to impress the casual observer.

Ed

[427sharpe]

NAPA sells a valve operated by a choke cable--$20 os so w/ chrome tip. The vacuum canisters are available from Jegs.

[jeff_taylor]

You might try placing a vacuum check valve between the intake manifold and the control valve. When the intake vacuum drops do to heavy right foot , the check valve will prevent air from relieving the vacuum in the line. When the vacuum returns (off the throttle ), then the line will continue to be evacuated by manifold vacuum. The check valve is less than 2 bucks at any parts store. If you add a canister for "vacuum storage" then you need to have a check valve between the canister and the manifold. You may also have a leak, but this should keep the heater from going on and off.

[Cobra20646]

Gary,
Some good advise for your problem. I like the simple idea of a manual valve too.
I was off last Monday and tore out the entire harness that goes between the engine and car. Over the years there has been more things done to this little car, and I got tired of finding cut wires that didn't do anything anymore but were still "hot". So now the car is sitting in the garage with it's dash out, new manual oil pressure, temp, and water temp gauges installed (but sensor bulbs not in place yet), new fuse block located, but no wires connected yet, new fan relay located, 2 mega fuses located in two 12 volt leads, one switched with the ignition key (40 Amp relay) and one always hot, each will feed a fuse block..... and a few other things here and there...... should only take about 5 or 6 hours to have a new harness created and installed and checked out.
I knew that if I started this project the weather would be just GREAT you all can thank me for making the sun shine and the temps return to near 70's.......... Your welcome!!!
Have fun
- Jim -

[Jack21]

Unless you're running something really radical for a cam, there should be plenty of vacuum for the heater valve. Simple test is if you have enough vacuum for the brakes to work, the heater valve should also. You have a vacuum leak or defective valve.

That being said, you may not want a vacuum operated water valve for the heater at all. It's either all on (too hot), or all off (no heat). A manual valve operated by a cable will regulate your heat better, and any auto supply store has them for a couple of bucks.

I'm about a 10 - 15 minute drive from you (small world, eh?). Come see how mine's setup.

[Silk]

Jack: I've been out of town for the past week - wasn't ignoring you. I'd like to see how you've done your heater - I'll e-mail you for directions.