Oil Pressure/Temperature Sensor Banjo Bolt

[SmuttyHutty]

I'm certainly not planning on being selfish with any bolts that arrive and am more than happy to post some on FOC. Harsc (Harry) has already been in touch and has first dibs as he is planning the same for his R3 and I'll send spares out.

Same rule as with 13Black - no guarantees are implied or given and any owners who choose to use these do so at their own risk.

[New Duke]

I watched the video that Ian linked to regarding using the Series 2 oil service port (the S1 oil filter location). I'll put a screenshot below for anyone that hasn't seen the video.

If an R3 owner only wanted one gauge, and that gauge was an oil temp sensor, and the sole purpose of the gauge was only to give a sense of whether the oil had warmed up enough to give it some revs... are there any reasons not to use that port for the sensor? With those as the very narrow criteria.

Honestly, me personally I would think that would be fine and rather suitable, but then again i've never tried it or know much. I had been reading the threads on RX8club and in this one a user was saying it would be ok for pressure and less so for temperature due to reduced flow?? Click here for link to thread.

[SmuttyHutty]

Question: the oil temperature gauge has arrived complete with sensor. I've popped it into a Banjo bolt. Am I going to restrict the flow of oil too much with it inserted this far?

[350matt]

best thing to do is make some measurements
if the opening area of the slots is much greater than the hole in the middle less your sensor tip diameter then yes its too restrictive

by eye I'd say to pull the sensor back a bit so its only the tip thats in the flow as thats all you need to read correctly

[SmuttyHutty]

best thing to do is make some measurements
if the opening area of the slots is much greater than the hole in the middle less your sensor tip diameter then yes its too restrictive

by eye I'd say to pull the sensor back a bit so its only the tip thats in the flow as thats all you need to read correctly

I had a play earlier and think I can use more PTFE tape to ensure a snug fit further up the thread so less of the sensor is protruding. I was concerned about having enough thread to bite but I think 4 or 5 full rotations of the sensor inside the banjo bolt will be enough, especially if it is snugged.

[30405]

Could you not space it out with some washers? Give it a bit more mechanical grip?

[SmuttyHutty]

Could you not space it out with some washers? Give it a bit more mechanical grip?

I've got a box of crush washers of various sizes. I might take a look in the garage in a minute...

[SmuttyHutty]

The sensor now looks like it belongs to the Kayan tribe with all of its neck rings but it seems to work well. To snug it finger tight it takes four full revolutions which is enough to get it solid. I'll use more PTFE tape on the day.

[13Black]

Whoa now.

The threads in the banjo bolts are 1/8 NPT, what is that sensor, straight threads? Or just a really narrow end of a tapered thread perhaps?

It required both threads to be tapered so that the taper on each make the seal once tight.

I wouldn't trust a straight threaded sensor in an NPT threaded hole.

Plus, multiple copper washer stacked don't do a great job of sealing either.

You're either relying on a copper washer for sealing, or PTFE tape, not both.
And the bolts aren't designed for compression washers out of the box, unless you've re-tapped them accordingly? 1/8 NPT is roughly similar to 10mm OD x 0.95mm pitch, which is quite a bit different to what's commonly available in straight threads.

[warpc0il]

Looks like you might need one of these
https://www.carbuilder.com/uk/brass-uni ... 1mm-female
or the other way around

[SmuttyHutty]

Whoa now.

The threads in the banjo bolts are 1/8 NPT, what is that sensor, straight threads? Or just a really narrow end of a tapered thread perhaps?

It required both threads to be tapered so that the taper on each make the seal once tight.

I wouldn't trust a straight threaded sensor in an NPT threaded hole.

Plus, multiple copper washer stacked don't do a great job of sealing either.

You're either relying on a copper washer for sealing, or PTFE tape, not both.
And the bolts aren't designed for compression washers out of the box, unless you've re-tapped them accordingly? 1/8 NPT is roughly similar to 10mm OD x 0.95mm pitch, which is quite a bit different to what's commonly available in straight threads.

The sensor is threaded 1/8NPT.

[13Black]

The sensor is threaded 1/8NPT.

Blimey, she seems to be a bit of a narrow one

Without the washers / tape, does it screw right in, using up all the sensor thread, and neck out at the hex?

If you haven't already, I'd perhaps try one of the others as some were tapped further than the others.

[SmuttyHutty]

Just ordered this as it seems the safer option:

[SmuttyHutty]

The sensor is threaded 1/8NPT.

Blimey, she seems to be a bit of a narrow one

Without the washers / tape, does it screw right in, using up all the sensor thread, and neck out at the hex?

If you haven't already, I'd perhaps try one of the others as some were tapped further than the others.

Yeah it thread all the way to the neck of the sensor. I'll have a play with some of the others but also see how this extener I've bought works with it as well.

[13Black]

Hmm. If some thread tape spaces it out without going mad then that might be my preferred solution, but that reducer could be the one if's not too long.

Such is the joy of the randomness of NPT fittings I guess.

I doubt it would, due to the shape, but I wonder if having the sensor tip "in the way" like that would do something to reduce any cross-talk between the incoming flows of the banjo bolt.
There's a similar plate between the two exhaust ports of the centre iron for the same reasons, also in some exhaust manifolds when collecting to a turbo.

[SmuttyHutty]

My concern was the sensor causing a drop in oil pressure due to restricted flow. It may make no difference at all, but I don't want to cause a problem where none currently exists.