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Hi there, I had a similar problem with my 70. Air slide was completely frozen shut. After missing out on a couple of used units on E-bay (that went for handsome sums) I decided to make my own. Not a difficult process. I started with a solenoid valve I bought on E-bay. You must get the right type, since you are basically porting "vacuum" (yes, I know, no arguments about porting what does not exist). The solenoid valve is mounted under the front of the plenum on the fender wall with a steel bracket. This is a normally closed valve. I bought a 3/8" valve. On one side I installed a nipple and a block style brass T. The short side of the T goes to the valve inlet. On one branch of the T I used a 1/2" SAE tap to create machine threads. Then I took a half inch bolt, about 1 1/2" long and ground a chamfer onto it's snout. When screwed into the threads, it can be adjusted down toward the opposite end of the T, creating a flow control valve. I have a half nut on the bolt as a lock. I bought two 3/8 pipe to 1/2 hose barbs. One is on the outlet side of the valve, the other is on the end of the brass T, opposite the adjuster screw. After threading it into the T, it forms the seat against which the beveled point of the machine screw will seat if it is screwed all the way in. The two hose barbs, ground down smooth, take my new hoses that attach to the plenum on either side of the throttle plate. The reason I chose to fabricate the flow control was to limit size. I could have bought all sorts of elegant valving off the shelf, but the solenoid valve is already a good sized piece. I didn't want to add any more bulk. This all fits neatly under the intake hose and can barely be seen. And it was fun to build too.
Next, I took my old AAV and cut off almost everything above the mounting flange. I know these can be taken apart and sometimes rebuilt, but I assure all purists, mine was beyond repair. To the flat surface I mounted an open-on-rise snap disc type switch from Allied Electronics. I tried several different switches before I got the right one. Not only is the temp range important, but the "slop" in the range is too. I'm fairly certain I ended up with OA-120-QC. Open on rise at 120F with quick connects (spade lugs). I drilled and tapped the face of the cut-off valve and attached this with machine screws. Make sure to remove the little shaft in the AAV that moves when heated. Otherwise, when it heats, now having been uncovered, it will jam itself against the snap switch and destroy it.
The solenoid valve is grounded to it's mounting bracket. The hot lead goes to the snap switch and then to an ignition hot source. With ignition on and engine cold, the snap switch sends power to the solenoid which opens, allowing air to bypass the throttle plate just as the AAV would. It took me a couple of tries with different temp range switches to get this right. Now, even if the ambient temp is 90, the cold engine closes the switch and thus opens the solenoid valve. I have my little flow control valve set so the engine idles perfectly at about 1100 RPM. I usually drive off before the valve closes, but by the time I reach the first stop sign, the valve has closed and the engine idles at base speed. I don't have pictures, and the car is not here at the house currently. But if there's anything I can help with and you'd like to give this a try, you can reach me at dpsam@sbcglobal.net
Best of luck,
DS
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