Quote:
Originally Posted by 70RAlll
You still have me lost on your setup.. one of your flappers ,using this plumbing, will always be exposed to vacuum. The thermo switch only has a chance to regulate one of the flappers with this plumbing. everyone can shoot me down on this, but I still think you have it wrong. I think the clips on the underside of the snorkel only hold the hoses to the flappers, the vacuum hose went directly from the intake manifold vacuum source to one of the ports on the thermo switch. I think you have gotten tied up with trying to make everything sit nice and neat under the snorkel, when it didn't. How does the thermo switch regulate the flapper that is right next to your "t"?? when the engine warms up, what is going to interrupt the flow of vacuum to the 1st flapper??nothing as I see it..
This is how I think the vacuum hoses ran:
1st Thermo Switch Port:vacuum directly from intake to one port of thermo switch
2nd Thermo Switch Port: other port of the thermo switch to the "t"
Both Flappers: "T" to each flapper.
That is the only way the thermo regulates both flappers.
|
That's what I thought too until I broke out the vacuum pump and heat gun, and actually tried it. As it turns out, both nipples on the sensor are plumbed in series. Pull a vacuum on one nipple and it transfers to the other nipple. In other words, both nipples are on the same side of the switch - not on different sides. The switch is normally closed until it heats up. You have a closed system when the car is cold and the engine vacuum activates both vacuum actuators upon start up, thereby closing the flappers. Once the sensor reaches operating temperature (or the preset intake air temperature of the sensor/switch) it opens and creates a controlled vacuum leak on the internal air cleaner side of the switch. This controlled leak allows enough vacuum bleed off that the vacuum actuators return to their normal position and the flapper doors open, and enough of a leak to keep vacuum from forming as long as it is open. This was a surprise to me, but it functioned perfectly in this fashion both in bench testing and once installed on the car. My thermac sensor may be faulty, but I don't think so. Actually both the old AC logo sensor and the new Delco unit functioned exactly the same.
I am open to being wrong - it happens a lot and I may very well be wrong here. However, spend a little time first with a vacuum pump and a heat gun and see if you don't come to a different viewpoint than you currently have. I've got two NOS sensors coming in the mail that I will also check. I'll be interested in hearing the results of your effort.
BTW - the part about doing it a certain way just so it was nice and neat was an unnecessary cheap shot. I may have thick skin, but that suggestion added nothing to your post that was pertinent in determining the correct technical way to do something. I may not have 10,000 posts, but there should be enough for the reasonable person to ascertain that I am not lazy and looking for the easy way out.