Worlds most accurate oil pressure gauge?

[cj847]

Check this video of my oil pressure gauge.



https://www.youtube.com/shorts/jSxa4LJeldo


My theory is that it has become sensitive to the oil pressure pulsations of the oil pump.

[Steeveedee]

Somewhere there is oil leaking, internally. There shouldn't be any pulsations due to the oil pump.

[Sheepdip]

Originally Posted by Steeveedee

Somewhere there is oil leaking, internally. There shouldn't be any pulsations due to the oil pump.

^^^^^^^^^^^What he said^^^^^^^^^^^

[cj847]

I hooked up an aftermarket gauge I had laying around and it read nice and smooth. I am not sure how a mechanical gauge wears out, I suppose it could be on its way out.
The truck is LS swapped. The LS uses an 8-9 gerotor oil pump which would produce pulsations, but I would think you would have to be reading pressure closer to the pump itself vs the back of the block.

[special-K]

I can't imagine an internal problem in oil flow that could cause such an instant response. I agree, the gauge must me failing. Until you replace it you can enjoy the privilege of having the world's most accurate oil pressure gauge

[steves1967]

For fun, ditch the 1/8" line and hook up a 1/4" line... then watch the gauge really move! To be fair- I do have autometer mechanical gauges, but with the bigger line you get a more accurate reading.

[Steeveedee]

Originally Posted by special-K

I can't imagine an internal problem in oil flow that could cause such an instant response. I agree, the gauge must me failing. Until you replace it you can enjoy the privilege of having the world's most accurate oil pressure gauge

It's just a Bourdon tube, and unless it's leaking in some weird way, the only explanation I have is that there is internal leakage in the engine. I'll make an example- let's say a rod cap is loose (not yet big time, or spun). The leak and pressure drop will correspond with the location of the cross-drilled holes in the crankshaft, as shown by the rapid fluctuation of the gauge. That's just one example, maybe it's a leaky lifter. I don't have any definitive answer, tbh. But having worked with machinery for decades, changing the gauge should not change what the video shows. I'm honestly stumped by this phenomenon.

As for Steve1967's comment, the only thing I'd expect is more rapid response to a change in oil pressure, but I'm not convinced that it would be that rapid. Again, I don't have an explanation, but that gauge doesn't agree with any oil pressure sensing I've ever seen.

[HO455]

Did this phenomenon start happening out of the blue?

It could be caused by the oil pump pumping air. Is the oil level correct? Does the oil look like it's full of small air bubbles. As Steeveedee said you could have an internal leak that is aerating the oil.

You might pull the distributor to inspect the drive gear and the oil pump drive for wear.

It may not be the problem but, changing the oil filter is easy and it's not impossible that it could be the issue.

I don't believe that the small brass gears in the guage will last very long with that much movement.

Good luck and keep us posted.