1970 datsun 510 temperature probe threading

[realdiehl]

i am trying to put an aftermarket mechanical temperature gauge in the 510 and the kit came with npt threading.i was previously told that the proper threading was bspt and i was told that i needed a 3/8 bspt to a 3/8 npt adapter.i purchased one and went to thread it into the housing and it was to tight and ended up cracking the thermostat housing.does anyone know the proper size that i need.

[ggzilla]

BSPT. Just don't use so much torque that you break it. Tiny fasteners need tiny torque. And also start it with your fingers. If it won't screw in by hand, something is wrong. Finally use the wrench to snug it up.

[realdiehl]

what size do i need.

[ggzilla]

The Datsun oil sender fitting is BSPT Taper 1/8" x 28

[D52E]

I believe I ended up using a 3/8 NPT fan switch from summit on mine (http://www.summitrac...parts/hfm-zfswf).

 

Edit: I just checked my order and this is the part I used on my thermostat housing.

 

[ggzilla]

for water temperature, this is stock Datsun threads. Do not overtighten or you'll crack the housing.

 

[realdiehl]

I used a 3/8 bspt thread and it only screwed into the housing about a 1/4 of a inch and ended up cracking it so i was thinking that it was the wrong size

[datzenmike]

I believe I ended up using a 3/8 NPT fan switch from summit on mine (http://www.summitrac...parts/hfm-zfswf).

 

Edit: I just checked my order and this is the part I used on my thermostat housing.

 

 

 

Fan switch in the thermostat housing???? why? It should be low on the rad or the return line into the motor to give the rad a chance to cool the water. This way every time there is a temp spike the fan comes on for nothing.

 

Only when the rad return water is starting to get too hot is a fan needed to increase the cooling. Just because the water coming out is hot doesn't mean the rad isn't working.

[D52E]

Sorry, I didnt mean to derail the original posting for the for sensor thread type...

 

I agree this is not the most optimal placement. I took this switch route on my setup because it was the most convenient method I found of easily implementing a fan switch on my current configuation. The 3/8" thermostat port was not being used for anything previously and if anything, it turns the fan on earlier (possibly reducing long term fan motor life a bit from more frequent on time).

 

The thermostat on my car is specd. for 180F and the switch comes on at 190F. The fan switch turns on after the thermostat is already open and flowing anyway so the radiator should be seeing near operating temperature coolant. While it's not the most optimal setup, it seems to be working for me at this time. Future modifications will take into consideration adopting a more optimal radiator placement (welding a threaded bung to the lower radiator area).

[ggzilla]

That's right. Datsun put the electric fan switch in the lower radiator hose. Or in the radiator on some models.

 

• 21595-M0206 SWITCH-THERMO
  
• ON: 83-87 C (181-189 F)
  
• OFF: 78-81 C (172-178 F)
  
• 05412-1600P GASKET
  
• 21596-M3000 ADAPT-THERMO SWITCH