Worlds most accurate oil pressure gauge? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cj847 · 08-24-2022, 01:56 PM

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** · 08-24-2022, 02:45 PM

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

**Sheepdip** · 08-24-2022, 07:36 PM

Quote:

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 · 08-25-2022, 02:39 PM

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** · 08-26-2022, 08:13 AM

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 · 08-27-2022, 11:09 PM

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** · 08-27-2022, 11:38 PM

Quote:

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** · 08-28-2022, 09:26 AM

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.

08-24-2022, 01:56 PM	#1
cj847 Registered User Join Date: Sep 2016 Location: Ozark, MO Posts: 579	Worlds most accurate oil pressure gauge? 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.

08-24-2022, 02:45 PM	#2
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,950	Re: Worlds most accurate oil pressure gauge? Somewhere there is oil leaking, internally. There shouldn't be any pulsations due to the oil pump. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

08-25-2022, 02:39 PM	#4
cj847 Registered User Join Date: Sep 2016 Location: Ozark, MO Posts: 579	Re: Worlds most accurate oil pressure gauge? 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.

08-26-2022, 08:13 AM	#5
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Worlds most accurate oil pressure gauge? 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 __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

08-27-2022, 11:09 PM	#6
steves1967 Registered User Join Date: Dec 2001 Location: Manteca, Ca USA Posts: 307	Re: Worlds most accurate oil pressure gauge? 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. __________________ '71 Chevy 3/4 Ton Longbed '22 Chevy Tahoe RST '67 Firebird- 8 sec street car '24 GMC CC 4x4 Duramax Dually

08-28-2022, 09:26 AM	#8
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,618	Re: Worlds most accurate oil pressure gauge? 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. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377



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