Stewart Warner vacuum gauge was not steady at idle

[dibbons]

Back when my parents purchased a special order '71 383 equipped Plymouth (road runner), I had our local mechanic install a couple of accessory SW brand gauges, manifold vacuum and oil temperature. However, the vacuum gauge always bothered me because at idle (around 12", if I remember correctly), the needle would kind of vibrate, shake, well, you know, it was not steady. At cruise speed it would not do that.

Now I am considering the addition of a vacuum gauge to one, two, or three of my project vehicles ('72 Satellite, '65 Formula S, '65 Signet convertible). I wonder if I will run into the same problem as before?

 

[RedFish]

Gauge sensitivity might be a factor. There are drawings/charts/whatever that show a variety of vacuum gauge needle responses along with suggestions of the fault condition each response indicates.
Vac Visual: Quick Guide to Vacuum Gauge Readings for example
Beyond that...my OEM vacuum gauge needle doesn't vibrate.

 

[12many]

You can try and insert a restrictor in the line/tube between the vacuum source and the guage, also called a damper. Something with a smaller inside diameter than the line. Short piece of smaller tubing, inserted in the existing line. That should smooth out your reading. A quick search should give you an idea.

 

[AJ/FormS]

Or just pinch the line. But I would leave it, because it's telling you the truth.
On an engine,closer to stock spec, it won't be doing that anyway.
But honestly, I don't see any value of having a permanently installed Vacuum gauge.
Nor for that matter, an engine oil-temp gauge.
But then the only decent gauge I run is the tach, and I hardly ever look at that either..lol.
I'm a streeter tho, I'm real busy keeping it between the curbs.

lol