Temp saftey switch
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Joined: Nov 2006
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From: Houston(clear lake)
Temp saftey switch
Hey guys I am looking for a sending unit style kit that I can set an alarm off if my temp gets too high in the engine. Anybody know of any kit that works with the threads on our heads or block for temp sensing?
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Posts: 572
Dave1980:
The only kits I ever found had 1/2" npt sending switches that work on the old SBC "wet" intake manifolds. So I made my own using a Stewart-Warner switch (can't read the part#) that was 3/8" npt which fits the LT1 head. (the port plug needs an 8mm square drain plug socket to remove) A 12 vdc piezo buzzer from radio shack gives the alarm and I put a light on the circuit too. Probably any 3/8 npt cooling idiot light switch will work. ISTR my switch closes at ~ 205°f. Since the coolant on the passenger side head has gone past 3 combustion chambers it's about 20°f hotter than the gauge (and water pump housing) senders in stop and go traffic my alarm will sound but goes silent when I start moving again. You might want to put some cooking oil in a small sauce pan and warm it on the stove to find out exactly what temp the switch closes. (Your wife/girl-friend will appreciate this!)
Ahhhh! ... I just remembered we've been down this road before, Dave. Must be winter time and tying up loose ends! If you're quick, the engine is cold and you leave the radiator cap on tight only a small amount of coolant will escape when the plug/switch exchange is done.
The only kits I ever found had 1/2" npt sending switches that work on the old SBC "wet" intake manifolds. So I made my own using a Stewart-Warner switch (can't read the part#) that was 3/8" npt which fits the LT1 head. (the port plug needs an 8mm square drain plug socket to remove) A 12 vdc piezo buzzer from radio shack gives the alarm and I put a light on the circuit too. Probably any 3/8 npt cooling idiot light switch will work. ISTR my switch closes at ~ 205°f. Since the coolant on the passenger side head has gone past 3 combustion chambers it's about 20°f hotter than the gauge (and water pump housing) senders in stop and go traffic my alarm will sound but goes silent when I start moving again. You might want to put some cooking oil in a small sauce pan and warm it on the stove to find out exactly what temp the switch closes. (Your wife/girl-friend will appreciate this!)
Ahhhh! ... I just remembered we've been down this road before, Dave. Must be winter time and tying up loose ends! If you're quick, the engine is cold and you leave the radiator cap on tight only a small amount of coolant will escape when the plug/switch exchange is done.
Last edited by NJ-LE; Dec 15, 2009 at 04:09 AM.
Thread Starter
Registered User
Joined: Nov 2006
Posts: 869
From: Houston(clear lake)
Dave1980:
The only kits I ever found had 1/2" npt sending switches that work on the old SBC "wet" intake manifolds. So I made my own using a Stewart-Warner switch (can't read the part#) that was 3/8" npt which fits the LT1 head. (the port plug needs an 8mm square drain plug socket to remove) A 12 vdc piezo buzzer from radio shack gives the alarm and I put a light on the circuit too. Probably any 3/8 npt cooling idiot light switch will work. ISTR my switch closes at ~ 205°f. Since the coolant on the passenger side head has gone past 3 combustion chambers it's about 20°f hotter than the gauge (and water pump housing) senders in stop and go traffic my alarm will sound but goes silent when I start moving again. You might want to put some cooking oil in a small sauce pan and warm it on the stove to find out exactly what temp the switch closes. (Your wife/girl-friend will appreciate this!)
Ahhhh! ... I just remembered we've been down this road before, Dave. Must be winter time and tying up loose ends! If you're quick, the engine is cold and you leave the radiator cap on tight only a small amount of coolant will escape when the plug/switch exchange is done.
The only kits I ever found had 1/2" npt sending switches that work on the old SBC "wet" intake manifolds. So I made my own using a Stewart-Warner switch (can't read the part#) that was 3/8" npt which fits the LT1 head. (the port plug needs an 8mm square drain plug socket to remove) A 12 vdc piezo buzzer from radio shack gives the alarm and I put a light on the circuit too. Probably any 3/8 npt cooling idiot light switch will work. ISTR my switch closes at ~ 205°f. Since the coolant on the passenger side head has gone past 3 combustion chambers it's about 20°f hotter than the gauge (and water pump housing) senders in stop and go traffic my alarm will sound but goes silent when I start moving again. You might want to put some cooking oil in a small sauce pan and warm it on the stove to find out exactly what temp the switch closes. (Your wife/girl-friend will appreciate this!)
Ahhhh! ... I just remembered we've been down this road before, Dave. Must be winter time and tying up loose ends! If you're quick, the engine is cold and you leave the radiator cap on tight only a small amount of coolant will escape when the plug/switch exchange is done.
I wonder if this would do the job? It looks like it is the right size, but I wanted something with a little higher temp rating.
http://www.jegs.com/i/Be+Cool+Radiat...75099/10002/-1
Here is another that has a higher rating, but not sure if it would work.
http://www.jegs.com/i/VDO/918/323421/10002/-1
Well not really sure, but want it to give me heads up that im heating up, and above norm. I am guessing in the 215 area.
Last edited by Dave1980; Dec 15, 2009 at 08:52 PM.
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Joined: Aug 2006
Posts: 572
Dave 1980:
The Be-Cool switch looks good. Like all the Be-Cool parts, the price is ridiculous... $10-15 would be reasonable. The VDO sender seems to be sender for a temp gauge that can read up to 250. You might look for a good local auto-parts store. It's was years ago when I worked the counter but the books used to have reference pages in back that gave physical and electrical specs plus application and cross-references for the parts. An idiot light switch for a 1985 Caprice might do exactly what you want! This spring, I'm going to get another electric water pump. At least the 42gpm Meziere or the 55gpm if it will fit (it's taller) and with the higher flow it may keep the temp at the rear of the cylinder heads closer to that in the front. Better for the engine too. If I do it, I'll PM the results to you. Good luck with the engine startup.
The Be-Cool switch looks good. Like all the Be-Cool parts, the price is ridiculous... $10-15 would be reasonable. The VDO sender seems to be sender for a temp gauge that can read up to 250. You might look for a good local auto-parts store. It's was years ago when I worked the counter but the books used to have reference pages in back that gave physical and electrical specs plus application and cross-references for the parts. An idiot light switch for a 1985 Caprice might do exactly what you want! This spring, I'm going to get another electric water pump. At least the 42gpm Meziere or the 55gpm if it will fit (it's taller) and with the higher flow it may keep the temp at the rear of the cylinder heads closer to that in the front. Better for the engine too. If I do it, I'll PM the results to you. Good luck with the engine startup.
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Joined: Aug 2006
Posts: 1,497
From: Orem, UT
The reason I asked is because I just out together a simple circuit for temperature switching on my Jeep, that is basically identical to what you're looking for.
The N.C. thermal switch is a small stainless steel capsule that is sealed shut with epoxy and trips at 100 degrees celcius (212 degrees F).
Check your PM's I'll send you more info.
Shown here is the thermal switch, and the one I'm going to use in my Jeep (epoxied in a 1/4" NPT fitting).
The N.C. thermal switch is a small stainless steel capsule that is sealed shut with epoxy and trips at 100 degrees celcius (212 degrees F).
Check your PM's I'll send you more info.
Shown here is the thermal switch, and the one I'm going to use in my Jeep (epoxied in a 1/4" NPT fitting).
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