Mistakes were made, my R34 Story

[Kinkstaah]

Yea I mean I know it exists, but finding (specifically) female BSPT to male NPT (i.e, to plug a Nissan OEM sensor into a 'standard' NPT port) was truly difficult. I don't think I'll recreate the setup I had in the past unless it's (possibly?) advisable with a stronger T piece made of steel, but who knows if the aluminium threads in the block become the next weak point etc.

Given it may need to be redrilled out and something tapped into it, it'll need to be Female BSPT to the something that ends uo coming out of the side of the block.

[Duncan]

yeah, so "something" should be -4 AN....to a hose....to a -4AN to NPT fitting

*edit* sorry, I surely have that backwards. The LS is from land of the free so it must be NPT at the block, and the Nissan sender is BSPT. But still, conceptually the same

[GTSBoy]

10 minutes on a lathe would be one way to achieve literally anything you want, too. (except for AN type stuff - just talking about M-F with BSP and NPT in any mix/combo).

[Kinkstaah]

I'm not quite understanding or I'm missing steps here, (I appreciate people are trying to inform my brain but I am of the dumb, especially today) - All I want to do is mount the male BSPT of the OEM sender into the system somewhere without it snapping the adapter via vibration.

The Nissan sender has a male 1/8 BSPT output. The block has a (very destroyed) 1/8 NPT input. I'm not really sure how a lathe assists with that, and also don't know anybody with a lathe, nor specifically what I would want to buy. I'm not really sure how adding additional adapters creates a better, more leak proof resilient seal here.

[Duncan]

Ahh. Well the block damage is a problem, you really need to run a tap or thread chaser through it to see if the threads can be saved, but any chips are likely to be bottom end bound which is bad.

Earls seem to have what you need if you want to stick with mounting direct on the block: https://rceperformance.com.au/parts/earls-straight-adapter-1-8-npt-male-to-1-8-bspt-female.html, but as I said above I'd recommend remote mounting the sender

[GTSBoy]

9 minutes ago, Kinkstaah said:

The block has a (very destroyed) 1/8 NPT input.

No it doesn't. It just needs an ezy-out to pull that broken bit of alloy out of the hole and presto chango - it will be back to being a 1/8" hole tapped NPT. as per @MBS206 recco.

10 minutes ago, Kinkstaah said:

I'm not really sure how a lathe assists with that

That would be for making what you had in alloy, in steel. If you wanted to do just that instead of remote mounting like @Duncan and I have been pushing.

A steel fitting would be unbreakable (compared to that tragically skinny little alloy adapter). But remote mounting would almost certainly be 10x better.

Small engineering shops abound all over the place. A lathe and 10 minutes of time = 2x six packs.

[GTSBoy]

And if you have to drill the oil block, then just drill it for 1/4" and tap it BSP and get a 1/8 to 1/4 BSP bush. The Nissan sender will go straight in and the bush will suit the newly tapped hole. And it will be real strong, to boot.

[Kinkstaah]

..this is the current state of that port.

I appreciate the info help (and the link to the Earls thing @Duncan). Though going by that it seems like 1/4 then BSP'ing it and using a bush may work.

I don't know where I'd be remote mounting the pressure sender... to... exactly. I assume the idea here is that any vibration is taken up by the semiflexible/flexible hose itself instead of it leveraging against the block directly.

I want to believe a stronger, steel bush/adapter would work, but I don't know if that is engineeringly sound or just wishful thinking given the stupendous implications of a leak/failure in this spot. What are the real world risks of dissimilar metals here? It's a 6061 Aluminum block, and I'm talking brass or steel or SS adapters/things.

[Duncan]

You are all good then, I didn't realise the port was in a part you can (have!) remove. Just pull the broken part out, clean it and the threads should be fine.

Yes, the whole point about remote mounting is it takes almost all of the vibration out via the flexible hose. You just need a convenient chassis point and a cable tie or 3.

[GTSBoy]

I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there.

Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.

[Kinkstaah]

1 hour ago, Duncan said:

Yes, the whole point about remote mounting is it takes almost all of the vibration out via the flexible hose. You just need a convenient chassis point and a cable tie or 3.

How do you propose I cable tie this:



To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less?

Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male)

Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush?



I am making the assumption the OEM sender is BSPT not BSPP/BSP

[GTSBoy]

1 hour ago, Kinkstaah said:

Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less?

Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme.

1 hour ago, Kinkstaah said:

Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male)

Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into.

1 hour ago, Kinkstaah said:

Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush?

The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from!

1 hour ago, Kinkstaah said:

I am making the assumption the OEM sender is BSPT not BSPP/BSP

It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.

[Duncan]

10 hours ago, Duncan said:

So I actually had the cover off my car today, here is a (bad) pic of the setup.

I have an oil cooler thermostat block, the temp sender is straight in there. The pressure sender has a short AN line to a T piece which is mounted (hopefully cable tied counts as mounted....) on the chassis.

Have a look at that (shitty) pic I posted. You can see AN -4 braided line coming to a -4 to 1/8 BSPT adapter, into a 1/8 BSPT T piece. The Haltech pressure sender is screwed into the long arm of the sender and factory sender (pre your pic) into the T side. You can also see the cable tie holding the whole contraption in place.

Is it better than mounting the sender direct to your engine fitting......yes because it removes that vibration as the engine revs out 50 times every lap and that factory sender is pretty big. Is it necessary for you......well I've got no idea, I just don't like something important failing twice so over-engineer it to the moon!

[Kinkstaah]

Thanks folks - I've saved a few links and I'll have to think of potential cable/adapters/buying fittings. First step will be seeing if I can turn the curren abortion of a port into something usable, then get all BSPT'y on it.

I did attempt to look at the OEM sender male end to see if it IS tapered because as mentioned you should be able to tell by looking at it... well, I don't know if I can. If I had to guess it looks like *maybe* 0.25 of a mm skinnier at the bottom of the thread compared to where the thread starts. So if it is tapered it's pretty slight - Or all the examples of BSPT vs BSPP are exaggerated for effect in their taper size.

[Duncan]

100% the factory sender is tapered, that is how it seals (well, that and teflon paste or tape)

[Kinkstaah]

Welp, good to know. Will have to wait awhile until steady hands with drills and taps are available.

In other news, these just arrived! I will weigh them for posterity.

Edit: 11kg each (or 10.9/11.1 depending on what my scale decides over multiple tests, the 18x11 don't seem to weigh noticeably any more than 10.5)

 

[Duncan]

Just one thing; tapping tapered threads is tricky. Taps are always tapered and you would generally run it as far as you can, but with a tapered thread you have to stop much sooner otherwise the wide part of the taper will run in too far and you will have to thread the sensor in too far too as well (possible that it will never make a good seal)

BTW nice wide wheels, I guess the top one is for the back!

[Kinkstaah]

Neg, the top one is actually for the front. The sizes are 18x10.5 +18 and 18x11 +32.
 

I measured many times but I'm sure I'll have problems as this is the thread for problems.

[Duncan]

Nice....looking forward to that update

[GTSBoy]

22 minutes ago, Duncan said:

Just one thing; tapping tapered threads is tricky. Taps are always tapered .... but with a tapered thread you have to stop much sooner otherwise the wide part of the taper will run in too far

Nah. You need 2x taps for anything that you cannot pass the tap all the way through. And even then, there's a point in response to the above which I will come back to.

The 2x taps are 1x tapered for starting, and 1x plug tap for working to the bottom of blind holes. That block's port is effectively a blind hole from the perspective of the tap.

The tapered tap/tapered thread response. You don't ever leave a female hole tapered. They are supposed to be parallel, hence the wide section of a tapered tap being parallel, the existince of plug taps, etc. The male is tapered so that it will eventually get too fat for the female thread, and yes, there is some risk if the tapped length of the female hole doesn't offer enough threads, that it will not lock up very nicely. But you can always buzz off the extra length on the male thread, and the tape is very good at adding bulk to the joint.