Coolant low pressure switch

A fuel pressure gauge would be a better psi fit. As I was driving the Mustang today it hit me that the Holly was looking for the same number range you were.

james
 
I would recommend a Hobbs type Press/Vac switch

http://www.alliedelec.com/Images/Produc ... 110009.pdf


They say they are factory set but you can set it yourself

The end has a rubber plug and under it there is has an Allen head then you just set up a multimeter and hook it to a pressure source and turn the Allen head to the desired setting

I could take some pics if you like
HTH
Davegt27
 
Finally got back to NAPA and the NAPA equivalent (3 psi, 1/8"NPTF, shorted with no pressure on sensor so low coolant pressure closes a switch and turns on a dash light) is NAPA PN OP6613, and it's $6.49 (not $18.99 like at Pegasus). That's good news for everyone except Kendal Jones who was such a Dick a few posts up that I convinced my buddy at NAPA HQ to put out an APB on Kendall so that if he tries to buy one.......his price is $18.99. :^) Seems fair to me.


That's the good news, bad news is that I really need the 2 terminal version of this as I will not be screwing it into a ground like the head or block. Can anyone assist? We scoured the Echlin parts book today but it wasn't much help. I could run separate ground from my inline adapter to ground.....that would be a bit bogus though. I'll do it if I can't find a proper switch with 2 terminals.
 
For a couple more cents an ingenious guy could come up with a simple design that had a green light under normal pressure that fliped to a red light at 3 psi. Kind of a fail safe deal because under normal circumstances the green light would be lit suggesting there is power to the system.
 
Would think you would need duel light to know, initially at least, as the system should not be under pressure when cold.
 
Protech Racing":35646lir said:
The LP light will come on when cold, depending on air volume as it warms up, will go out.
Click to expand...

^ I understand.

Guys, when I used the word fail safe that means to me that I know on going that there is or is not power. We are talking about not smoking a motor, correct. Water temp warning is to late. A few cents extra makes my wallet feel good.

As racers we all know, different strokes for different folks. :)
 
The problem with using a Normally Closed switch in your circuit that causes the light to go out when you have pressure is that you can burn out a bulb and not have an indication.

The SPDT switch like David suggested is a good idea. The contact arrangement is also called a 'Form-C' style contact. Wire a red light to the Normally Closed contact and a green light to the Normally Open contact. One of the two lamps will always be on. If both go out, there is a problem with the circuit or one of the lamps is bad.

Otherwise, if you can only get a switch with a single contact, get a normally open contact that closes on rising pressure, and wire up a Green light to the switch. The light will be off when cold, but will come one when warmed up with pressure i.e. On = Green = Okay, Off = low pressure or bad bulb.

If you have to use a Normally Closed contact, use a bright LED instead of a conventional lamp for reliability.
 
I really like the SPDT low AC/refrigerant switch idea from David........I'll check my pals at NAPA
 
David, do you have an example 3 wire SPDT AC pressure switch PN??? I looked in the Echlin catalog and they all appear to be 2 wire units. Spade connections would be sweet too.
 
Im confused, you guys are trying to build a fail safe system but are relying on a $5 sensor from NAPA??? No point in wasting a heat cycle on your $800 set of tires, cause your $5 sensor gave a false alarm.

If you want a fail safe system, get a 0-20 psi gauge and a warning light. When the gauge shows 0 psi, and the light is on, you know you have a problem. When the light is on, but the gauge shows 15psi, you know its a false alarm.
 
The thread originator set the cost limits. :mrgreen:

Your choice Jay. I found it under "Low Cost" SPDT pressure switches. :wink: Do they mean $20.00 or less??? Only a call will tell.

http://www.hycontrol.com/pneumatic_hydr ... es-oem.php

Address details:

Hycontrol USA, LLC
12 Euharlee Road
Suite H
Cartersville, Georgia
GA 30120
USA

Tel: +1 770 606 1212
Fax: +1 770 386 5877
Email: sales@hycontrolusa.com
Web: www.hycontrol.com

Contact details:

Wayne Holder, Sales Manager
Jay Pruehs, Marketing Manager
DeAnna Edwards, Internal Sales
 
Up date; Installed the latest switch on the Turbo Jett( Chumper) What are the odds of having some coolant loss with this car? 100%. it is just a matter of time.
Anyway. the switch/light comes on until around 180* and may come on at low rpm. meaning that the switch must be around 6-8#. The light goes back out as you rev the engine over 3000rpm . It will stay out as the engine gets up to full running temp/pressure.
Works fine. MM
 
Hi Mike,

I've been running one for years. You will also find that the light comes on if the cars temp drops during the race. For example, if you're running close behind someone and then get clear of them or if the races gos double yellow.

Kyle
 
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