TomoHawk Posted November 16, 2003 Share Posted November 16, 2003 What are the vacuum solenoids for? I can't see what. Can you remove them and the vacuum bottle and just run the vacuum to the heater control? if you need another vacuum source, there seems to be 2 or 3 lines coming off the intake. thx. Quote Link to comment Share on other sites More sharing options...
zcarnut Posted November 16, 2003 Share Posted November 16, 2003 Can you remove them and the vacuum bottle and just run the vacuum to the heater control? The problem with removing the vacuum bottle is that the level of intake manifold varies with engine rpm and throttle position. At wide open throttle there is not enough vacuum to operate the heater air flow valves. That's why Nissan used the vacuum bottle. It's like having a "storage container" of vacuum. However, I removed the vacuum bottle on my 260Z show car, but I tapped into the brake booster with a "T" fitting on it's hose for a vacuum source for the heater valves. Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted November 16, 2003 Author Share Posted November 16, 2003 I bet if you cut apart a vacuum solenoid, you would find out wht they were used. I would bet that it's just a piston with a spring, and the piston acts like a valve. Like Zcarnut suggested, the bottle is a resevoir for vacuum, and the solenoids are used to scavenge whatever useable vacuum there is. It might be possible to get away with only one vacuum solenoid, mounting it directly to the bottle. Quote Link to comment Share on other sites More sharing options...
zcarnut Posted November 17, 2003 Share Posted November 17, 2003 Using electric control the vacuum solenoids direct the vacuum (stored in the bottle) to the appropriate locations. On the early Z cars one of the solenoids is used to direct vacuum to the vacuum operated heater/AC vent control bellows. The other one is used to operate the fast idle valve that is needed when the AC is turned on. This compensates for the engine loading by the AC compressor. In practice only one of these solenoids is necessary–the fast idle solenoid. And those of us who have the triple carbs even eliminate this one as well. BTW, the later ZX cars (and most of the other Nissan vehicles) changed the vacuum bottle to a smaller one that is black plastic (less noticeable) and has the solenoids mounted on it. Maybe you should consider using one of these. Lastly, another problem with the early vacuum bottle is that the stock check valve that is needed to prevent the vacuum from leaking off back into the manifold is not longer available. You have to use an aftermarket one. Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted November 17, 2003 Author Share Posted November 17, 2003 So since my car has no a/c, I won't be needing any of those solenoids. Just a check valve (maybe). I haven't noticed any wires going to them either. thx. A few less pieces of (rusty) junk out from under the hood. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.