1) Does anyone know what approximately the coolant temp. difference is between the radiator neck (coolant circulating-full open themostat) and the cyl. head coolant temp.(sender location)?????????

2)What I was thinking (I know, thats how I get in trouble) If the gauge is reading inaccurately, couldn't I experiment with different size resistors, spliced in series, to alter the resistance to the temp. gauge, thereby changing the reading???


I'm fighting a cold so this might all be a Nyquill induced hallutionation :jester

 

The cylinder head temperture is going to be highest, and the only one that your really interested in, As you go lower on the block you encounter slightly more metal and less surfaces of friction per se, however the cylinder head temp is really the most critical. It should be somewhere at or around 200 degrees. I can't understand why you would want to alter the final reading. If you had say a temperture sensor in the lower radiator hose it should read a much lower temp as the coolant has just passed thru the radiator and is going back into the block. But then that's how the system works?

 

I'm not looking to change the final reading, just make it as accurate as possible if necessary.
I figured that if I knew the water temp at the top of the neck, the only place I can physically measure the temp, and the correct for the difference between that temp and the supposed head temp, I could get the cockpit gauge accurate.


[Modified by shoptek, 10:09 PM 5/20/2002]

 

You could use a heat sensing gun to get your information. Summit sells one in the catalog, or if you call around, you may be able to borrow one.

 

Isn't the temperature in the intake manifold the highest? To get to the intake - the water has passed already through the cylinder heads and should have the highest temp just before exiting the block through the upper radiator hose

:cheers:

Olivier

 

The water at the thermostat is about 10-15 degrees hotter than the water in the heads.

Why?

The water in the heads is just entering the heads, the water at the thermostat is after the heads so it has picked up the heat from the heads.

Don't be putting resisters inline, in parallel or inanything with the temp sensor. You will be changing the slope of the temperature coefficient of resistance and the gauge will become very inaccurate. The slope change can be calculated with a little simple vector math :lol: but it WILL change!

Measuring the temp of the heads and thinking it is the same as the water flowing through them is silly, it's MUCH more complicated than that.

The best thing to do is to calibrate your sensor by hooking it up to the car and sticking it in a pot of boiling water ( assuming sea level, otherwise you will have to adjust ) and noting what temp the gauge indicates. There is no way to actually 'calibrate' these things:rolleyes: so you just have to remember what 212' is

If you are wondering who to believe, I worked at www.Minco.com for 14 years developing precision lab quality temperature sensors and the like.:D:D


[Modified by 427V8, 7:09 AM 5/21/2002]

 

This is true, but I believe that you can adjust the sensor output with resistors and make it accurate for the operating range of the engine. Sure, it barely registers on the gauge when the temp is at 160, but my modified sensor is within 5% of the original sensor from 180 - 210 degrees. I measured the resistors in a pot of water on my stove with an ohm meter and a candy thermometer. If it ever goes much over the 210 mark, I'm pulling over and seeing what is wrong.

 

Yep, as long as you understand how you are changing the response of the gauge go fer it...