"Idiot light" vs. Oil Pressure Gauge

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hotrod swinger

hotrod swinger

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Good day everyone and happy Friday!

I've been running my small block with the so called "idiot light" for a couple of years now with no oil pressure gauge. My engine is a hi-po 360 LA that I had professionally built in 2020. I ran a mechanical oil pressure gauge for awhile just to ensure everything was ok, then removed it along with my other aftermarket gauges when I fixed up all my factory gauges a few months later.

I know I could run both but I kind of like the look of my dash without gauges hanging underneath and I'm wondering, do you really need an oil pressure gauge for a street car when you have a functioning oil warning light? Every single time I start the car I turn the key to run to ensure my oil light is working before cranking.

What do you say, leave well enough alone?
 
i'd maybe fit a higher pressure warning light sender. i know they're available here in the uk so there's no reason you should have issues sourcing one in the states. with a stock sender by the time the light comes on it's usually too late, unless you're just idling in traffic. and that assumes you notice it as soon as it comes on, lol.
neil.
 
I had just the oil light on Vixen for the longest time. I got curious just what kind of oil pressure she had, so I plumbed in a manual gauge and mounted it under the hood. She idles on the relief valve cold at about 75PSI. Hot she idles about 50 and as soon as the throttle is blipped, you can see the needle stop like a STONE on the relief valve at about 75. I'm like you. I don't like the clutter inside so I mounted mine under the hood. If the light works, use it and don't worry about it.
 
RustyRatRod said:
I had just the oil light on Vixen for the longest time. I got curious just what kind of oil pressure she had, so I plumbed in a manual gauge and mounted it under the hood. She idles on the relief valve cold at about 75PSI. Hot she idles about 50 and as soon as the throttle is blipped, you can see the needle stop like a STONE on the relief valve at about 75. I'm like you. I don't like the clutter inside so I mounted mine under the hood. If the light works, use it and don't worry about it.
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I like the idea of mounting it under the hood, I was actually thinking about mounting gauges under the hood. It would be nice to have a voltmeter, water temp gauge and oil pressure gauge in there.
 
I know that these cars came with pretty basic instrumentation but unless you're running a fairly stock engine, I wouldn't feel comfortable not knowing about the oil pressure. All of the A and B body cars I've owned had temperature and alternator gauges anyway.
 
My solution on my Duster was install Voltage and Oil Pressure gauges in a custom mounting bezel that I made to fit in the uncut radio hole in my dash. I am not running the dash oil light and have bypassed the ammeter.

IMG_0379.jpeg
 
Here is an oil pressure gauge Plumbed in along with the working electric dash gauge and idiot light. So that is actually showing 3 ways to see oil pressure.

Always like a gauge to be able to see the real pressure.

20240927_143017.jpg


'89 D100, 318


☆☆☆☆☆
 
There are Bluetooth senders that keep the gauges on your smart phone. No clutter under the dash.
 
I am pretty sure I noticed my oil filter going into bypass mode on cold starts last winter.. the Pressure gauge read 5-7 PSI lower than normal until the oil warmed up a little.. That was on a slant six with 80K. Recent oil pan removal for dipstick soldering, and paint. Valvetrain looked clean when I had adjusted the valves.. The oil might have been synthetic, and I had not owned/driven the truck very long. I should have just changed the filter as a test, but I did not think of it, and changed the oil as well. Problem solved..

My point being I want an oil pressure gauge... AND and idiot light that is bright enough for me to notice...
 
get a super bright led bulb. maybe also wire a buzzer/beeper (a door open one would do) alongside the warning light. you won't have to worry about missing the light then.
neil.
 
chryslercruiser said:
I am pretty sure I noticed my oil filter going into bypass mode on cold starts last winter.. the Pressure gauge read 5-7 PSI lower than normal until the oil warmed up a little.. That was on a slant six with 80K. Recent oil pan removal for dipstick soldering, and paint. Valvetrain looked clean when I had adjusted the valves.. The oil might have been synthetic, and I had not owned/driven the truck very long. I should have just changed the filter as a test, but I did not think of it, and changed the oil as well. Problem solved..

My point being I want an oil pressure gauge... AND and idiot light that is bright enough for me to notice...
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The bypass valve is in the oil pump.
 
RustyRatRod said:
The bypass valve is in the oil pump.
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Isn't that called the "oil pressure relief valve" and controls the oil pressure from going sky high on a cold start with thick oil, for when people start the engine at -30, drop it in gear and try to merge onto the fast lane because they are late for work..

What do you call the spring loaded valve that is IN the oil filter for when the filter gets plugged?
 
chryslercruiser said:
Isn't that called the "oil pressure relief valve" and controls the oil pressure from going sky high on a cold start with thick oil, for when people start the engine at -30, drop it in gear and try to merge onto the fast lane because they are late for work..

What do you call the spring loaded valve that is IN the oil filter for when the filter gets plugged?
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They do the same thing. One dumps oil back into the pan (valve in the oil pump) the other dumps oil straight into the engine bypassing the filter. They are both bypass valves. That said, I've not seen a bypass valve in an oil filter in years, but of course I might not be paying attention, either. LOL All I am aware of now are the anti drain back valves. .......and they really aren't worth two cents.
 
I'll come back and comment further from recent experience. Modern filters do indeed have a bypass valve, but I've first hand experience that they don't work well or at all. I recently had a big block Chevy I built wipe several cam lobes (Thanks Comp) and it stopped the filter up and lost oil pressure. It was a WIX filter, too. So the bypass valve failed. I'm actually kinda glad it did. It probably saved the rest of the engine, because I was watching the gauge when it fell and killed the ignition.
 
Wvbuzzmaster said:
I started with adding 14” Tuff wheel but found the 15” Challenger wheel worked better with manual steering and ability to see my gauge cluster. Plus it looks better too I think.
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I used it because it was the biggest diameter on I had in my stash, but it does look good.
 
the valve in the filter is a non return valve. fitted so the oil doesn't drain back when standing, therefore giving you a pre primed system on start up. the filter doesn't need a pressure relief valve as it's upstream of the one fitted in the pump so would be redundant.
neil.
 
mygasser said:
the valve in the filter is a non return valve. fitted so the oil doesn't drain back when standing, therefore giving you a pre primed system on start up. the filter doesn't need a pressure relief valve as it's upstream of the one fitted in the pump so would be redundant.
neil.
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Well, if you look it up, you get articles that say there IS a bypass valve in modern filters. I believe they are confusing the two. The WIX I used had no bypass valve at all and barely had an anti drain back valve.
 
RustyRatRod said:
The WIX I used had no bypass valve at all and barely had an anti drain back valve.
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Ive got 4 more Wix filters in my stash, but the last one I bought back in 2022 was made when they were owned by Mann and Hummel... Not happy to have paid that much for a crappy filter...

I am presently searching for a Wix replacement filter manufacturing company that makes GOOD filters, like the Wix of yesteryear... Not sure if they are all crap, but the one I bought for a subaru was not worth the money spent..
 
chryslercruiser said:
Ive got 4 more Wix filters in my stash, but the last one I bought back in 2022 was made when they were owned by Mann and Hummel... Not happy to have paid that much for a crappy filter...

I am presently searching for a Wix replacement filter manufacturing company that makes GOOD filters, like the Wix of yesteryear... Not sure if they are all crap, but the one I bought for a subaru was not worth the money spent..
Click to expand...
Well this was chosen not by me but by my wife's cousin who owns the engine. I run nothing but Made in USA Motorcraft filters.
 
YES both the light and a mechanical gauge UNDER THE DASH NOT UNDER THE HOOD. By the time the light goes on much of the damage is done. Changes in pressure as things START to go wrong can be seen as changes in typical gauge readings. Fluctuation in the needle can indicate low oil levels after pan damage or other oil loss on the road that would never show up on the light. I can't even conceive of installing a new engine without installing a mechanical gauge inside the car before turning it over.
 
A warning light is like being told you have a disease as you reach the point to need surgery.
A gauge spots abnormalities before they become a bigger issue.
 
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