The appears to be three spots to place a temp sensor on a SBC. One in the side of the block between #1 and #3 cylinders.... one the opposite side between #6 and #8... and then in thru the top of the intake manifold at the front... Your thoughts on which spot is best?
i like it in the intake manifold right by the thermostat those pipe plugs in the heads can be real hard to get out sometimes
Rigth now I'm using the 1/3 spot but I was wondering if there is a temp difference between the top - water going out and the cylinders... water coming in... and how much difference ther would be.... strange **** I think of standing in the garage with a beer...
I found a major dif in temps in these 2 locations when I stuck in a control for an electric fan. I believe the 1/3 spot in the head is the best. In my experience, the gauge responds more quickly and accurately in the head location. Eventually they would read close on a longer drive but not a shorter one due to water flow characteristics.
Always been told to use the head for the temp gauge. On some of the newer stuff the temp senders may have to have adapters. So i go the the manifold. My two cents.
The head locations will show a temp rise under load, this may not be seen at the thermostat. Another point, if you are extremely low on coolant the gauge at the head will tell you immediately where-as the intake will take longer.
I know, I made a tool from a bolt last week. Took me a couple days to figure out how to remove it, it was in there pretty good. I like mine in the heads.
I plan on dual guages from both cylinder heads. The prime concerns in a temp guage are 1. overheating? and 2. combustion efficiency influenced by operating temp.
I use the driver side head if it has the boss. I know guys that run one in the head AND one in the intake. They claim it gives them a better picture of what's going on but maybe they just have a gauge fetish or something.
Guage mfgs recommend putting the temp sender in the intake manifold close to the thermostate. If you put it in the block, you may get false readings and the guage will indicate high temp after you shut off the engine if it is close to the exhaust manifold.
I know I'm bringing this from the dead- but doing a google search and I'm looking into the same issue. I want to put my sending unit between 1&3 on the head. Problem is, the sending unit I currently use is 1/2" NPT on the intake boss- and the ports on the head are smaller, 5/8" x 18 tpi straight threaded. Can I use any old sending unit that is 5/8 thread? I'm having trouble looking online, because everyone specifies the application, but not the thread size. A 350 will live with the unit on the intake or head, so how do I know which size I'll get if I order a stock part? Also, are these units calibrated to the application/gauge? Or are they interchangeable the world over?
Looks like there is another part no for the 3/8 NPT (5/8" thread), "TSU-64". Still curious how these things work though, and whether they are interchangeable across applications.
You will need to know the ohm value on the gauge and sender and will have to match it up. I bet if you call Cl***ic Inst. and tell them what gauge you have, they can tell you a sender that will work. That's how I would approach it anyway. Dennis D
I think on older engine they used the intake, I have a 94 engine with head temp and seems the runs cold most all the time with new thermostat. I think intake is best, close to thermostat.
I've tried em all. Makes very little difference. Water travels faster than you might think in a cooling system. Whatever's easiest for you. (you'll probly get a better average temp if you go closest to the thermostat housing)
It makes a huge difference which location you use. The heads will heat up much faster, and will also be a hotter temp all the time. I measured both locations on my 327, and before my 170 degree T stat opened the head 1/3 location was already at around 190-200 degrees. Once the stat opens it drops, but still read 10-15 degrees higher than the intake manifold location. Remember the head location is right next to the combustion chamber and exhaust outlet, so it will always read hotter, whther it's 1/3 or 6/8.
If it made a huge difference the engineers wouldn't have added the different locations. Keep in mind the supposed hotter, in head locale came later on on the Chevys, after more data was gathered. If it were a bad and inconsistant idea they wouldn't have added it, much less kept it for years to come. I agree about the head being hotter, but it's the FAST traveling water (not the hot cast iron near the chambers) that contacts the temp sensor and gives more uniform readings between the different areas. I suppose you're right in that there will be a big difference in the few minutes that the thermostat's closed.........................
There is another option on Chevys anyway, I use a thermostat housing for a truck application that has the temp sensor hole cast in the top of the thermostat housing, that way it reads the temp of the coolant leaving the engine.
I think a lot the factory locations might have had to do with packaging. Another reason for moving them probably had to do with emission controls, what needed to see what and when. Back in the first days of computers and electric fans a car may have as many as three temp. sensors, one each for the electric fan idiot light and the computer. I seem to remember cars with a fitting in the thermostat housing that had a temperature controlled vacuum regulator in it. Or it won't show it at all. Air doesn't transfer heat worth a damn. My students didn't put a lower radiator hose all the way on. The idiot light never came on. Drove it to my night job, then on the way home I knew I had a problem when it started pinging and rattling. Mama wasn't happy getting out of bed to bring me tools and water.
A buddy had a take out motor (can't remember the make) with the temp sensor mounted near the thermostat housing. He told me that when he first started it up in his rod, it ran good for awhile but then the temp gauge spiked up rapidly indicating overheating. So he'd shut it off and after it cooled down, would start working the problem. I think the final ****ysis / guess was that the motor's water level was low or that it had air pockets in the jackets, so when some of the water started to turn to steam and / or any bubbles of steam worked their way past the thermostat, it would cause to gauge to peg falsely. I don't know if this is true or not (a little help, please) but ever since then I've kinda been suspect of sender locations near the thermostat. Gary
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