this is the stock temp gauge on the 70 rallye dash. so i have my new engine in, and took it for a test drive. it was already about 170 when i took it out, but it seemed to climb quickly to 220+, so brought it back home. drove about a mile total. was able to remove the radiator cap, which seemed strange as it was supposedly so hot, and topped it off, (first time firing it in the car).

took it out again and same thing. again was able to take the radiator cap off. got hold of an infrared temp sensor, and the highest reading was 150 at the water pump neck. 140 at the top of the radiator, 110 at the bottom, all normal considering it was only driven a mile or so.

with my previous engine in there it would run around 180 or so, but seemed to heat up on the highway, and didn't like slow moving in hot weather. that all seemed reasonably normal.

how do i test the gauge and figure out what is wrong? unless the infrared sensor is wrong, (which i doubt, mainly because i was able to open the radiotor cap both times), then i've got another issue here.

another little tidbit, when i got the car, i discovered a 10 ohm resistor in line for the temp sensor. i took it out, and things seemed normal. so it may be possible that all this time my other engine was running cool?

thoughts?

When you redid the motor did you put a new temp sensor in it?

I've heard most of the new ones have the incorrect resistance and you have to add resistors.

Check you infered against a known source. But sounds like it is fine.

Did you run the enginge with the radiator cap off until the thermo opened and water was flowing? If of not you may have a air lock in the block..

put the old sensor in, and it did change some, but still runs above the 200 mark, whereas it didn't with the previous engine.

checked it with an infrared down at the machine shop, no more than 170 after a good little romp.

so how do i diagnose this?

so, any suggestions on how to diagnose this?

Is the location of the sensor in the same part of the waterpump housing on both engines ?

I have used a couple of MP alum housing and the temp sensor is located in a different location , I plug it and drill and tap it in the factory location.

Personally I wouldn't be relying on the factory gauge for accurate temp assessment .

Did you reuse the same carb as the old motor and how about the timing? Could need more fuel to keep her cool!

New temp senders are junk. See if you can find a nos one or go with a mechanical gauge

Just add resistors and calibrate it to your infered gun.

Sintro once suggested the ohm resistance amounts to start out with. They come in a pack from Radio Shack.

does your gas gauge read high as well?

can you check the voltage out of the VR?

the stock vr trys to regulate 5 volts.
a test light should show it pulsing, as it is a set of contacts that open and close to make the average 5 volts.