[HELP] OEM VTEC Solenoid oil pressure switch thread size

[Z06Chris]

Anyone know what size thread this is?

I thought it would be 1/8 BSPT like all the old school Hondas but it isn't.

The top one in the photo is the Defi Oil Pressure Sensor. It is 1/8 BSPT.

Bottom is the OEM oil pressure switch.

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[Patrick Bateman]

Looks like M10x1.5

Do you not have a set of calipers?

 

[metal_driver]

Anyone know what size thread this is?

I thought it would be 1/8 BSPT like all the old school Hondas but it isn't.

The top one in the photo is the Defi Oil Pressure Sensor. It is 1/8 BSPT.

Bottom is the OEM oil pressure switch.

I ran into the same issue when I tried to install an oil pressure guage transducer at that location as there was no room left on my sandwich plate...
After doing some research I was pretty sure it was 1/8 BSPT and I bought that adapter but when my mechanic tried to install the 1/8 BSPT adapter to the oil sensor port it leaked pretty badly so it came back off...

Hopefully someone will have an answer as I wold like to really get my oil pressure gauge up and running before next rack season.

 

[17RGuy]

@Patrick Bateman is right, grab a set of calipers to figure it out the easiest.

If you don’t have calipers, bring the oem one to a hardware store carrying extensive hardware from Hillman fasteners. Most Ace hardwares around me have a ton of Hillman fasteners, which in turn means they have all the thread gauges to figure out what thread and pitch you have.

 

[BlueFalcon]

I'm in need of a BSP oil temperature sensor for my HKS sandwich block- where is everyone sourcing a good quality BSP threaded sensor with pigtail?

 

[17RGuy]

I'm in need of a BSP oil temperature sensor for my HKS sandwich block- where is everyone sourcing a good quality BSP threaded sensor with pigtail?

I purchased an Innovate oil pressure/oil temp gauge. I had to re-tap my hks sandwich plate because it was not 1/8” bsp. It was a metric thread.

 

[BlueFalcon]

I purchased an Innovate oil pressure/oil temp gauge. I had to re-tap my hks sandwich plate because it was not 1/8” bsp. It was a metric thread.

Ohh whaaaa?

I was totally under the impression it is a BSP threaded connection... I thought the manual/item description even lists it as such... ?

 

[17RGuy]

Ohh whaaaa?

I was totally under the impression it is a BSP threaded connection... I thought the manual/item description even lists it as such... ?

You are correct with your impression. Mine even said that as well. I tried multiple 1/8” threaded nipples, sensors, etc I had laying around. None of them threaded past one thread in the hks sandwich plate.

Maybe I had a freak one that someone at hks quality control missed, but I re-threaded it and it was perfect. Had I not already had the tap, I most likely would have sent it back to the vendor I bought the oil cooler from for replacement.

I should mention as well, the little set screw plug HKS put in the sandwich plate was excessively glued in and super wobbly when chasing the threads. The more I’ve thought about it, I would bet a lot of money they tapped mine with a metric tap on accident.

 

[shadow]

You are correct with your impression. Mine even said that as well. I tried multiple 1/8” threaded nipples, sensors, etc I had laying around. None of them threaded past one thread in the hks sandwich plate.

Maybe I had a freak one that someone at hks quality control missed, but I re-threaded it and it was perfect. Had I not already had the tap, I most likely would have sent it back to the vendor I bought the oil cooler from for replacement.

I should mention as well, the little set screw plug HKS put in the sandwich plate was excessively glued in and super wobbly when chasing the threads. The more I’ve thought about it, I would bet a lot of money they tapped mine with a metric tap on accident.

HKS is 1/8" BSP which is 28TPI.
Innovate's sensors are 1/8" NPT which is 27TPI.

They are both 1/8" and tapered but have different threads per inch.

https://www.valvesonline.com.au/ref...NPS threads have a,per inch) are listed below.

 

[17RGuy]

HKS is 1/8" BSP which is 28TPI.
Innovate's sensors are 1/8" NPT which is 27TPI.

They are both 1/8" and tapered but have different threads per inch.

https://www.valvesonline.com.au/references/threads/#:~:text=BSP vs NPT&text=BSPT equivalent is NPT and BSPP's equivalent is NPS.&text=NPT/NPS threads have a,per inch) are listed below.

You sir are correct. I installed this months ago and your comment made me go double check my taps. My innovate pn 3913 is npt not bsp. I kept the plug in my tool box and it is not bsp. The plug has a ton of gray thread sealant and the thread pitch of what has to be a m4 x 0.70 thread pitch.
Thank you for checking my sloppy misinformation shadow!

 

[shadow]

I kept the plug in my tool box and it is not bsp. The plug has a ton of gray thread sealant and the thread pitch of what has to be a m4 x 0.70 thread pitch.
Thank you for checking my sloppy misinformation shadow!

It is PT 1/8" which is the same as 1/8" BSP.

 

[BlueFalcon]

It is PT 1/8" which is the same as 1/8" BSP.

Thanks for confirming.

So, the original question still remains- where are you guys sourcing a high quality BSP oil temp sensor with tail?

Really not trying to use an adapter...

 

[shadow]

Thanks for confirming.

So, the original question still remains- where are you guys sourcing a high quality BSP oil temp sensor with tail?

Really not trying to use an adapter...

Most JDM brands come with 1/8" BSP sensors. However, the gauges' calibrations are most probably specific to their sensors. You can verify by looking at the sensor's calibration/technical sheet, if available.

So, if your gauge came with a 1/8" NPT sensor, good luck. Unless, that company makes a 1/8" BSP version.

 

[Patrick Bateman]

M4?

1/8” pipe thread has an OD of a bit over .4”. Which equates to ~10mm.

That pic the OP posted with the unknown thread is a straight thread, too.

Good lord. Y’all are making this unnecessarily difficult.

 

[BlueFalcon]

Most JDM brands come with 1/8" BSP sensors. However, the gauges' calibrations are most probably specific to their sensors. You can verify by looking at the sensor's calibration/technical sheet, if available.

So, if your gauge came with a 1/8" NPT sensor, good luck. Unless, that company makes a 1/8" BSP version.

Interesting point about the sensor calibration-

I have an 1/8" NPT sensor for use with a non-jdm brand gauge. I could use an adapter, but it's not ideal, and was interested in exploring other options. I probably won't have access to any further detailed data about the sensor or calibration parameters.

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