A/C Vacuum chamber
#1
A/C Vacuum chamber
Slowly restoring my 1970 442 and I cannot find information on the source of vacuum for my Vacuum chamber that operates the A/C vent controls. I have extensively searched the Service Manual for a diagram or picture. Where does the large vacuum line on the bottom left run? Where does this vacuum line plug in for vacuum? Can someone share a picture? Right now I have a small line stuffed in it and am sharing with the transmission modulator off the intake manifold. Your picture or correct location would be great help to me. I may need to T in somewhere else but it would be good to know where it SHOULD go. My TCS solenoid is gone and I don't feel like I need a new one. Car runs fine without it. Yes that distributor is disturbing and I will be replacing it eventually with something that is or looks much more factory. Previous owner chopped up my air cleaner to fit that ugly beast in. It is on the list of things to repair.
Last edited by KEN442OKC; July 18th, 2022 at 07:24 AM.
#2
There should be a 3/8" vacuum elbow on the back of the intake manifold that it can go to. No need for hose clamps on vacuum lines. The factory never did that. The vacuum brake booster, that vacuum reservoir and the transmission modulator all go to manifold vacuum.
#3
Your 70 Chassis Service Manual will have all systems for vacuum. In 72, there was a fitting on the back of the intake, and it had two ports if you had AC, one for the AC and the other for the heat riser vacuum door. If you had W-25, that little hose to the heat riser got a T for the flapper OAI door, too. There was also a bigger port for the brake booster back there.
In front of the carb, there was another intake port with a hose that got teed for TCS manifold source, and modulator. Off the carb was ported vacuum source for the TCS. The TCS then went to the vacuum advance.
If the TCS is gone, go straight from that fitting to the modulator and put the vacuum advance in the carb port. Or, plug the carb port, and keep the tee and run the dizzy off the front port with the modulator.
My heat door is not even hooked up.
In front of the carb, there was another intake port with a hose that got teed for TCS manifold source, and modulator. Off the carb was ported vacuum source for the TCS. The TCS then went to the vacuum advance.
If the TCS is gone, go straight from that fitting to the modulator and put the vacuum advance in the carb port. Or, plug the carb port, and keep the tee and run the dizzy off the front port with the modulator.
My heat door is not even hooked up.
#4
Here's a picture of a 1970 455 intake manifold that still has the vacuum fittings installed - I put an arrow showing the one for the AC vacuum canister.
Last edited by Fun71; July 18th, 2022 at 01:12 PM.
#7
#8
Yeah, you are right there is an Accel stock size coil that the cover will fit onto. The Accel HEI SuperCoil coil is larger than the factory coil, so the cover won't fit.
Last edited by Fun71; July 20th, 2022 at 09:11 AM.
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