Oil Pressure Switch

[Dung Beetle]

So I had a motor seize due to a faulty oil pressure switch. I just had the motor rebuilt and I don't want to have the same problem again. I was thinking of installing a pressure gauge and the stock pressure switch. This would give me a better reference of what was going on. This leads to a couple of questions. So i will start with the things I do know.

The motor was a 1600 DP now rebuilt to 1776 with a performance grind cam and high rev springs (single springs). The carbs are empi HPMX 40 dual carb setup. Added an oil cooler under the rear package tray (Baja Bug).

The questions.

Has anyone considered wiring up the oil switch in parallel to a micro-controller that could kill the ignition?

Is there a recommended oil pressure gauge people are using preferably electronic?

Besides the problem I mentioned below, can anyone think of why else this may be a bad idea?

I figure with a small micro in the mix, I could put a dwell time on the activation of the switch before the ignition is killed. This would likely solve the light flickering at idle that some see killing the ignition.

I know this could be rife with hazards, I.E. engine getting shut down on the freeway due to a faulty switch. Also I would have to work out how to start the car with the light on. I have some ideas on this as well.

[glutamodo]

The stock switch is not a gauge, it is a simple on-off switch. On (connecting to ground) when low pressure, off when there is a certain level of oil pressure.

Really, if you have a reliable such stock switch it should be fine. Reliable usually means made in Germany or Europe...

Now hooking that up to a kill switch is an OK idea, but it might make starting the engine more difficult.
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[old_man]

I'm going to say hooking it up to kill your engine is a bad idea.

1) Starting will be very hard
2) It can sometimes flicker at idle on a hot day in traffic, now it will just die.
3) Most importantly, it has the potential to kill your engine at speed without warning. This would be a safety issue.

Might be easier to just hook it up to a buzzer.

[andk5591]

There are time delay relays that you could use to work with the "kill" circuit to allow a certain amount of time before becoming active. Not hard to find and not expensive. Really thinking it would not be hard to do.

VDO has a dual function sender that will provide oil pressure for a gauge and still use the idiot light.
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[Dale M.]

Generally no oil pressure- no run switches need to have bypass circuit so engine can start and build oil pressure... Also as mentioned if you have weak oil pressure engine many die in traffic as oil pressure drops out at idle speeds (stop signs) ...

JEGS and Summit racing and probably many others "speed" dealers have a three terminal switch that will not allow engine starts or to run if oil pressure is not present.... But needs some sort of bypass for any start up (generally a push button on dash) ...

https://www.summitracing.com/parts/hly-12-810
https://www.summitracing.com/parts/atx-os75
https://www.summitracing.com/parts/vdo-230-504

Besure if getting switch its m10 straight thread and not 1/8 NPT...

A microcontroller just add's more expense and design headaches to system where a simple switch may be all that is needed or have enough complexity to make you want to cry when trying to just drive your car....

No matter what system you try it all comes back to the sensor (oil pressure switch) and if it fails what headache it going to cause you...

Dale
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[andk5591]

Not going to work all through this - have a Ghia on the lift that needs ball joints, BUT I believe this would work.
https://www.amazon.com/Delay-Relay-Board-Switch-Mo...amp;sr=8-7
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Woodie 69 VW woodie (Hot VWs 7/12).
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Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[mikedjames]

I use a stock pressure switch and a separate electronic gauge sender together on an extender screwed into the switch hole.

So the light goes out at the correct pressure, and also the electronic gauge indicates the pressure.

With two oil pressure loss indicators, I think I have enough information to decide whether to press on or not.

For a while I used a relay slaved off the electronic sender to operate the warning light, set to go on at about 4 PSI,
I gave up on this when one day the old engine got very hot (thermostat rod stuck ?) , the electronic sender decided to malfunction around 240 degrees F and the oil pressure went 'negative' at idle RPM.

I also often see a slight increase in sump oil temperature as oil levels decline before it reaches the bottom of the dipstick.
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I suggest adding a buzzer into the circuit, the stock idiot light is too ez to miss in a lot of lighting situations.
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[Dung Beetle]

[hobbybob517]

you could have it like a shift light, no way you would miss that.
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[bsairhead]

Your motor did not seize due to a faulty oil pressure switch. All that switch does is give you a visual indicator that you have lost pressure. It might give you enough time to shut down but it was not the root cause of the failure.

[EverettB]

I was wondering how the switch made your engine fail too?

Did it not work at all?
Did the light come on with the key before you started the car?

Just curious...
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[nextgen]

I like the Buzzer Idea, I sit back and my light gets covered by my steering wheel.

Getting old, maybe use an old bug horn. BEEEEEEEEEEEEEEEEEEEEP!!

Serious buzzer is simple and a good idea.
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[chrisflstf]

Buzzers can be very annoying also. May want to add a switch to cut off the buzzer

[Bruce Amacker]

[Dung Beetle]

[old_man]