I have only checked by blowing through it, but screwing the restrictor in and out does adjust the air flow. When screwed in hard, down onto the tapered seat, it cuts off all flow.Does the flow through the restrictor change if it’s wound in and out or should it just be wound onto a seat?
Cannot answer that one. The red band feels like the sort of material that fibre washers are made from, but I have no idea what it is covering. The photo shows a pair of machine screws in the barrel, and there is similar pair on the opposite side. I have not found any sort of vent or release button, and really do not want to dismantle it without knowing what to expect inside.What's inside the chrome barrel with the red band around it? If it's a check valve, the gauge down-stream of it would read peak pressure (I'd expect there to be a little vent/release button somewhere if that was the case though)...
I think you're right, especially with the short needle sweep and the needles on the same scale. Would make a great way to read engine compression.It's not a differential pressure gauge as there's only one connection.
There is a restrictor in the system somewhere - *if* this were in the 'curly' leg, the combination of the volume in the pipe and the restrictor would really dampen the movement of that gauge. *If* the other gauge was connected directly to the inlet, it would be very responsive.
It looks, to me, very much like a compression tester (as post #2 ) that gives both instantaneous and average cylinder pressure.
I think you're right...
Unfortunately, there seem to be no features around the inlet that are not shown in the earlier photos. Looking directly up the stem, all that can be seen is the conical seating (to mate with the adaptors), which has with a bore of only about 2mm diameter.Can you take more close up photos of that part of the gauge and also one looking directly up the stem?
Is a 200 psi limit reasonable for this style of engine?
To add plausibility to your suggestion, you might need to consider the adapters that are part of the device. One of them is 1/2" BSP; one is 3/4" BSW; the other (the tapered one) is unknown, but might be for a gas cylinder.
You have to find a device that has one of those threads with a direct connection to the source of pressure. Will any of those adapters fit any documented spark plug thread? If not, that eliminates spark ignition engines. You are left with compression ignition engines. Do injectors have these threads? Is a 200 psi limit reasonable for this style of engine?
Spanner openings across flats:What about the spanner any clues on it
doubt it’s a compression tester. If it was used with the needle valve/restrictor in it could rattle loose and drop into the bore.
It’s not a non return valve and seats fully closed when wound in meaning its loose in the threads when open. It’s more like a radiator vent valve than a Schraeder valve.you more or less need a schrader type valve to get good compression readings. It's got be somewhere in the line.