Temperature sensor in A14

[markate]

We bought a Roadster with an A14 swapped into it. We immediately noticed that the temp sensor was running well over 250F. However, when we put a temp gun to it, we were around 180-190. It seems pretty obvious that something has been lost in translation from the Roadster dial and the 210 motor. We are going to try and chase the wires and see if we can find anything, but I am hoping someone has run into this issue before and has some wise sage advise to offer.

 

Thanks in Advance,

[Draker]

You could try to adapt the temp sensor from a roadster?

[Draker]

You could verify the sensor is reading the correct temp by comparing it's resistance value to spec. Or just replace it..

 

You could compare the resistance spec to the roadster spec and see if that's the problem your having.

[Draker]

You could also measure resistance from the harness to the cluster to see if maybe thats where the issues is :)

[datzenmike]

Does it read 250 at all times the key is on? even a cold engine?

 

If so, the sender wire is pinched and grounded.... it will read full HOT on the gauge.

[markate]

Does it read 250 at all times the key is on? even a cold engine?

 

If so, the sender wire is pinched and grounded.... it will read full HOT on the gauge.

No, it starts at below zero and move up. It seems like the scale is wrong. Guessing it has to do with the resistance, as mentioned above

[markate]

You could also measure resistance from the harness to the cluster to see if maybe thats where the issues is :)

That is a great suggestion. I will look into that. any idea where I could find the spec of what it should be for each car?

[datzenmike]

Higher resistance would lower the reading. Maybe add some resistance to lower over all readings?

[filthy forever]

add a resistor thats value is about 200 ohms in series, and it should bring down the temp about 30 degrees

[datzenmike]

Unless the gauge is pegged and would normally go higher. Seems like a good place to start though. Add resistance as needed until the gauge matched the IR gun.

 

FWIW the nut that fits the block that the sender screws into is the same for the Roadster and the A14 so a roadster sender should fit the A14.

[MikeRL411]

Early roadsters had an SAE thread on this fitting. 1968 and a halt and on roadsters and 510s had a metric thread, don't know what the A14 thread was so use whatever originally threaded collar that is on your current engine, the "cartridge" is the same dimension when installed.  I could not find the Datsun spec temperature sender for my RL411 so bought the 510 set and ditched the metric threaded collar.  Works perfectly.

[markate]

Early roadsters had an SAE thread on this fitting. 1968 and a halt and on roadsters and 510s had a metric thread, don't know what the A14 thread was so use whatever originally threaded collar that is on your current engine, the "cartridge" is the same dimension when installed.  I could not find the Datsun spec temperature sender for my RL411 so bought the 510 set and ditched the metric threaded collar.  Works perfectly.

That is great information! Thank you. I ordered new sensors from Rock Auto and I have a few extra dials for read out. I will see what I get and start looking at this problem variable by variable. 

 

Thanks again!

[markate]

Received the sensor and tried to install it yesterday. The old one did not want to come out (not too uncommon, I am sure). After much struggle, it came out, but we managed to chew up the threads of the head pretty bad. I am hoping to chase them and get this put back together, but my girlfriend accidentally took the nut portion of the assembly with her out of town and I can't use it to get the measurements until tomorrow. Does anyone have an idea what the thread is? If I recall, I measured the pitch as metric 16. Any help would be appreciated as I was hoping on working on it tonight.

 

Thanks!