Hi Guys,
As an ongoing search for bits to do this dash replacement, I thought it a good time to install an oil pressure (light) switch to trigger a warning light at low oil pressure.
I found the Tridon Catalogue this morning, and i'm having a bit of trouble making heads and tails of it!
Does anyone know what they mean by their Normally Open and Normally Closed settings - I.E - Is Normally open when the pressure is exceeded? or when the pressure drops below the set pressure.
And also they have different pressure alternatives - 0.2bar, 0.3bar, and 0.4 bar - I calculate these to be: 2.9Psi, 4.3Psi and 5.8Psi. Would this be correct? I want something around 20-30 Psi!
Cheers!
Oil Pressure Senders
Started by
Tiny
, Dec 27 2008 11:04 AM
73 replies to this topic
#1
Tiny
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Posted 27 December 2008 - 11:04 AM
#2
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Posted 27 December 2008 - 11:57 AM
I havent calculated it Tiny but 1 bar is roughly equivalent to 14.5 PSI from memory so it looks like your calcs are pretty good, What sort of pressure do you have at idle when the car is warm? Im just trying to think when my car is warm at idle its pressure is around 25psi and you wouldnt want the light coming on at that stage. May be a good question for others that run a light but i would have thought light to come on under 20psi??
Normally open and normally close would be its sitting state, so if you take it out its packet and test with a meter a normally closed switch would have continuity or basically if you had power to it, then it would have power out. I would think a normally closed switch would be the go because when you turn on ignition then your light will come on showing you that its functional, then start the car the pressure goes up and switches light off.
Normally open and normally close would be its sitting state, so if you take it out its packet and test with a meter a normally closed switch would have continuity or basically if you had power to it, then it would have power out. I would think a normally closed switch would be the go because when you turn on ignition then your light will come on showing you that its functional, then start the car the pressure goes up and switches light off.
Edited by SS Hatchback, 27 December 2008 - 11:59 AM.
#3
Tiny
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Posted 27 December 2008 - 12:14 PM
Thanks Rob! I have around 30-40Psi at idle when hot hot, so 20 Psi is about where i want it!
Autometer make a sender that is 15 Psi or 30 Psi, so i'd probably grab the 15 Psi! ( I was looking for alternatives to autometer!).
Thanks for the description on NO/NC because that was baffling me!
Cheers mate! Hope your Chrissy was good!
Autometer make a sender that is 15 Psi or 30 Psi, so i'd probably grab the 15 Psi! ( I was looking for alternatives to autometer!).
Thanks for the description on NO/NC because that was baffling me!
Cheers mate! Hope your Chrissy was good!
#4
_Drag lc_
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Posted 27 December 2008 - 01:21 PM
tiny,
did you think about using a hobbs switch as you can adjust the pressure at withch they switch and they come with 3 terminals for no/nc?
as that is what we are using to switch the big red autometer warning light
Thanks Hayden
did you think about using a hobbs switch as you can adjust the pressure at withch they switch and they come with 3 terminals for no/nc?
as that is what we are using to switch the big red autometer warning light
Thanks Hayden
#5
_why-psi_
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Posted 27 December 2008 - 02:17 PM
im using an autometer 15psi switch to trigger an autometer prolite warning light and also have it wired to a relay which cuts the fuel pumps when pressure drops due to engine trouble or a crash
#6
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Posted 27 December 2008 - 02:36 PM
Gday Hayden,
I've heard of a Hobbs switch, but no! I had not thought of using one! Where do you get them? Is there any info on how they work that i could read up on?
Why-psi: How do you get the fuel pump to prime the system when starting? I take it if there is no oil pressure then the pumps would not activate at all? Your setup is what i was planning to use!
I've heard of a Hobbs switch, but no! I had not thought of using one! Where do you get them? Is there any info on how they work that i could read up on?
Why-psi: How do you get the fuel pump to prime the system when starting? I take it if there is no oil pressure then the pumps would not activate at all? Your setup is what i was planning to use!
#7
_why-psi_
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Posted 27 December 2008 - 03:00 PM
to prime the fuel system i put a button switch on the dash which supplies a relay with the earth to switch the pumps on. so turn on ignition, push button to prime then start.
it took a lot of messing around with relays to get it to work properly. ill try dig out the diagram i drew up for it
it took a lot of messing around with relays to get it to work properly. ill try dig out the diagram i drew up for it
#8
_torbirdie_
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Posted 27 December 2008 - 03:11 PM
im using an autometer 15psi switch to trigger an autometer prolite warning light and also have it wired to a relay which cuts the fuel pumps when pressure drops due to engine trouble or a crash
Is this for a road car?
Perhaps you have considered the pros and cons, but suggest for anyone else to reject this setup for safety reasons. Having the motor designed to cut out if oil pressure drops could you leave you in an exposed situation where you were relying on the car to keep moving, accelerate etc for the next second or so. Your life maybe worth more than a new motor.
One reason car manufacturers dont build cut/out switches for temp and oil pressure in the 1st place, though the cynical may say its so you can buy a new engine after the warning lights are ignored.
Just put an extra loud warning device in and be your own judge on whether you should cut the motor.
Edited by torbirdie, 27 December 2008 - 03:17 PM.
#9
_why-psi_
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Posted 27 December 2008 - 03:23 PM
pretty basic. use a 2 pole relay. pin 87A is live when the solenoid is off ( have oil pressure). then when pressure drops, the solenoid sends the earth to pin 86 which drops power to 87A and activates 87 lighting up the warning light and dropping feed to the fuel pump relay and cutting the pumps. to prime tap a button into the wire leading to the pressure switch to trip the relay and allow ignition feed to go to the pump relay.
the motor wont cut right away as there will be still fuel in the bowls unless its EFI
#10
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Posted 27 December 2008 - 03:43 PM
Thanks WhyPsi, that's really interesting!
A Prime Button, That's a really good idea.. I might use a 3 position switch... for the fuel pump ON - Off - Momentary using the momentary to prime the pump!
I think that birdie is right in that you wont want the engine to cut out right away, but as youve said even if the pumps turn off you've got some time with what's in the fuel bowls.
My plans are to run a light and buzzer ( eventually) to warn of low oil pressure.
Maybe as a safety cutout a tachiometric relay would be batter as if the dizzy isnt spinning then you really dont need the fuel!
I think there are alot of people who will benefit from this discussion!
A Prime Button, That's a really good idea.. I might use a 3 position switch... for the fuel pump ON - Off - Momentary using the momentary to prime the pump!
I think that birdie is right in that you wont want the engine to cut out right away, but as youve said even if the pumps turn off you've got some time with what's in the fuel bowls.
My plans are to run a light and buzzer ( eventually) to warn of low oil pressure.
Maybe as a safety cutout a tachiometric relay would be batter as if the dizzy isnt spinning then you really dont need the fuel!
I think there are alot of people who will benefit from this discussion!
#11
_GMH355_
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Posted 27 December 2008 - 06:19 PM
G'day Tiny I am actually in the process of wiring Ant's carter fuel pump. I will be using an oil pressure safety switch to cut power to the fuel pump. I am planning on using this product from summit, link below.
Summit oil pressure safety switch
This safety switch opens the circuit once oil pressure drops below 7psi. I will not use it to cut engine power, but to cut power to the fuel pump. As mentioned by Why-psi I will also include a primer button to prime the pump with the ignition on without the engine running. This is labelled on the diagram as the optional bypass switch. The wiring diagram also shows how to wire in a light to show low oil pressure. I can't see why you couldn't also wire in a buzzer with the light.
Summit oil pressure safety switch
This safety switch opens the circuit once oil pressure drops below 7psi. I will not use it to cut engine power, but to cut power to the fuel pump. As mentioned by Why-psi I will also include a primer button to prime the pump with the ignition on without the engine running. This is labelled on the diagram as the optional bypass switch. The wiring diagram also shows how to wire in a light to show low oil pressure. I can't see why you couldn't also wire in a buzzer with the light.
#12
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Posted 27 December 2008 - 06:24 PM
Tiny,
here is a few pics of the hobbswitch we use they are quite expensive i think but we use one side for oil warning light
the other switches the hour meter as to get a good idea of how much work the engine has done. sorry for the poor
quality of the pic that is under the rubber plug you can adjust the pressur at witch it switches by adjusting this grub srew.
i just got them from the local auto electrial place.
thanks Hayden
here is a few pics of the hobbswitch we use they are quite expensive i think but we use one side for oil warning light
the other switches the hour meter as to get a good idea of how much work the engine has done. sorry for the poor
quality of the pic that is under the rubber plug you can adjust the pressur at witch it switches by adjusting this grub srew.
i just got them from the local auto electrial place.
thanks Hayden
#13
_HRV74_
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Posted 27 December 2008 - 08:01 PM
Hi all
Thanks for this topic Tiny!
Have just bought an Autometer Mini Pro-Lite, and the 30 PSI switch. Currently running an Autometer Pro Comp oil pressure gauge which will remain - was wondering what sort of T-fitting people use to run the Pro-Lite AND a gauge? Couldn't find anything in the Autometer catalog. Are they just a fairly standard part that can be found at most performance shops?
Thanks!
H
Thanks for this topic Tiny!
Have just bought an Autometer Mini Pro-Lite, and the 30 PSI switch. Currently running an Autometer Pro Comp oil pressure gauge which will remain - was wondering what sort of T-fitting people use to run the Pro-Lite AND a gauge? Couldn't find anything in the Autometer catalog. Are they just a fairly standard part that can be found at most performance shops?
Thanks!
H
#14
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Posted 27 December 2008 - 08:37 PM
HRV74, just a brass T peice with 1/8 npt threads will do. i have one on my 202, screwed a male to male adaptor into the oil pressure sender hole, then the t peice so i could have the line for the gauge come out of the T alongside the block towards the rear and the sender screwed into the T perpendicular to the block. came up pretty neat. think i got the T from robbos.
#15
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Posted 27 December 2008 - 08:46 PM
Ah i see, thanks for that why-psi, it looks the goods! 
Cheers
H
Cheers
H
#16
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Posted 28 December 2008 - 08:26 AM
hrv74,
this is what we are going to use aswell as the switch and gauge we are also going to plumb the accumulator into the end of the t aswell
all the fittings we have are proper Ryco Hydraulic fittings i just drilled and tapped it 1/8 to accept the hobbswitch.
Thanks Hayden
this is what we are going to use aswell as the switch and gauge we are also going to plumb the accumulator into the end of the t aswell
all the fittings we have are proper Ryco Hydraulic fittings i just drilled and tapped it 1/8 to accept the hobbswitch.
Thanks Hayden
#17
Tiny
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Posted 28 December 2008 - 03:09 PM
Fantastic info gentlemen!
Thank you very much, as i mentioned this is one of the things that all us revheads like to do to keep our engines safe! We spend so much making them go hard and re reliable that it's awesome to do something to keep them safe too!
Thanks for the heads up on the Hobb Switch Hayden That's something i'll look in to! It's obviously been working fine with oil pressure? I thought they were only good for vaccum (air?)
Frank: Wanna come by here after your finished at ants and help us with the dash re-wire/stereo install/thermo fan wiring/warning light setup hehehe! But no seriously that switch is something i saw in the autometer catalogue and it's similar to the ones i saw in the Tridon catalogue. The tridon ones are made to replace OEM stuff, so knowing the right size and pressure reading is the hard part!
Where did you get that one from frank and how long did it take to arrive?
Harve: Did you have the autometer mini pro-lite or did you buy it? It's something i'd like to use as my warning light too, but i think i've left myself little or no time to find/buy one before i need this job done!
Just because i'm too lazy to go out to the shed and unscrew and measure the oil pressure guage on the monaro, Would anyone happen to know the standard oil pressure port size on a 350/400 Smallblock Chev?
Thanks again gents!
Thank you very much, as i mentioned this is one of the things that all us revheads like to do to keep our engines safe! We spend so much making them go hard and re reliable that it's awesome to do something to keep them safe too!
Thanks for the heads up on the Hobb Switch Hayden That's something i'll look in to! It's obviously been working fine with oil pressure? I thought they were only good for vaccum (air?)
Frank: Wanna come by here after your finished at ants and help us with the dash re-wire/stereo install/thermo fan wiring/warning light setup hehehe! But no seriously that switch is something i saw in the autometer catalogue and it's similar to the ones i saw in the Tridon catalogue. The tridon ones are made to replace OEM stuff, so knowing the right size and pressure reading is the hard part!
Where did you get that one from frank and how long did it take to arrive?
Harve: Did you have the autometer mini pro-lite or did you buy it? It's something i'd like to use as my warning light too, but i think i've left myself little or no time to find/buy one before i need this job done!
Just because i'm too lazy to go out to the shed and unscrew and measure the oil pressure guage on the monaro, Would anyone happen to know the standard oil pressure port size on a 350/400 Smallblock Chev?
Thanks again gents!
#18
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Posted 28 December 2008 - 05:28 PM
Tiny,
i used to work on ewp (boomlifts jlg)and some of them had them on the kubota engines from the factory.
also we adjusted the switch up to 35psi for the strip last time and it would come on idling in the end(800rpm)
so keep that in mind i realise that the idling is to low.
Thanks hayden
i used to work on ewp (boomlifts jlg)and some of them had them on the kubota engines from the factory.
also we adjusted the switch up to 35psi for the strip last time and it would come on idling in the end(800rpm)
so keep that in mind i realise that the idling is to low.
Thanks hayden
#19
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Posted 28 December 2008 - 05:35 PM
Thanks mate!
I worked on alot of EWPs! theyre fun things! (Safer than cherry pickers i reckon!)
Thanks mate, I'm going to go to American autos tomorrow to see if i can get teh warning light and some switches!
Cheers
I worked on alot of EWPs! theyre fun things! (Safer than cherry pickers i reckon!)
Thanks mate, I'm going to go to American autos tomorrow to see if i can get teh warning light and some switches!
Cheers
#20
_GMH355_
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Posted 28 December 2008 - 07:46 PM
.....Where did you get that one from frank and how long did it take to arrive?....
Tiny, I have a link to the summit racing website in my previous post just under the picture of the switch. Around 5 days to arrive. I see you mentioned thermo fan wiring as well. I have been looking into a tridon fan switch for Ant's AU thermo fans. This is what I intend buying. I was told it will screw into a 308 intake manifold, don't recall if chev is the same thread.
Part number details below. Costs are around $20-25
Tridon TFS110 Fan switch Thread - 3/8 GAS
Circuit - Normally Open Ground
Temp Range: 87�C to 82�C
While we are on the subject of thermo fans, does anyone see a benefit in using an oil pressure switch to actuate the thermo fans so the fans don't automatically start when you try to crank a hot engine? In this way the starter motor will get all the current and the fans will only turn on after you have oil pressure.
#21
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Posted 28 December 2008 - 07:51 PM
Thanks for the info Drag lc, much appreciated.
Tiny: I bought the Mini Pro-Lite about a month ago, just haven't got around to getting it fitted yet. I ordered one and it arrived 2-3 days later, so i'd say you'd have no probs getting your hands on one from American Autos. Just in case it helps, the Mini Pro-Lite Warning Lite (in black) is part no. 3239. The 30psi Pressure Switch is part no. 3242 (i assume this would be the go for your 400 chev).
Cheers
H
Tiny: I bought the Mini Pro-Lite about a month ago, just haven't got around to getting it fitted yet. I ordered one and it arrived 2-3 days later, so i'd say you'd have no probs getting your hands on one from American Autos. Just in case it helps, the Mini Pro-Lite Warning Lite (in black) is part no. 3239. The 30psi Pressure Switch is part no. 3242 (i assume this would be the go for your 400 chev).
Cheers
H
Edited by HRV74, 28 December 2008 - 07:57 PM.
#22
Rockoz
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Posted 28 December 2008 - 08:00 PM
GMH355. If you are thinking of this idea for a particular reason I would like to know why.
If you start your car cold i reckon you will pul;l more amps than when hot. If your car has problems starting when hot then I think you may have other areas that need to be looked at. But given that I could design a circuit for you.
If you start your car cold i reckon you will pul;l more amps than when hot. If your car has problems starting when hot then I think you may have other areas that need to be looked at. But given that I could design a circuit for you.
#23
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Posted 28 December 2008 - 08:06 PM
Tiny,
or if you are really concerned about not seeing the oil light you could just use the big auto meter warning light like we did.
Thanks Hayden
or if you are really concerned about not seeing the oil light you could just use the big auto meter warning light like we did.
Thanks Hayden
#24
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Posted 28 December 2008 - 08:20 PM
Thanks for the response Rockoz, no problems at the moment. Engine is a hi comp 308 stroker and I know the AU fans draw a lot of current. The fans are a new install, maybe I am being overly cautious but thought it wouldn't hurt to wire in the oil pressure switch so the fans don't draw current from the starter on a hot start. Thanks for the offer of designing a circuit, if you have something at hand you can post up I am sure others would also be interested in having a look. Always happy to learn something new.
Tiny, not intending to hijack your thread. I am guessing you are interested in this as well.
Tiny, not intending to hijack your thread. I am guessing you are interested in this as well.
#25
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Posted 28 December 2008 - 08:38 PM
Actually a simple timer circuit would probably be best for that. Reverse of a turbo timer so to speak. Fans not to turn on for (x) seconds. Will look at whats available and get back to you
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