Another oil pressure gauge thread -- factory sender thread size?

Post by **bleet** » Thu Apr 17, 2003 5:20 pm

I know this is my first post but I'm a newb and need some help....

1989 240SX KA24E (sohc)

I need to install an oil pressure gauge and want keep the factory sender, so I need to make a "T". Thing is I can't find anyone or anything that can tell me what the threads are into the block. Actually the threads appear to go into a plate that is mounted to the block which the oil filter also connects to.....or something....

Thanks to anyone who replies.

Post by **95_240sx** » Thu Apr 17, 2003 5:20 pm

on me s14, they are british threads, which will throw you off, i cant remember what they are off the top of my head.

Rick

Post by **Open4Cycle** » Thu Apr 17, 2003 5:20 pm

1/8 NPT

Post by **silviaNE** » Thu Apr 17, 2003 5:20 pm

1/8 bspt not 1/8 npt. YOu can get adapter from most hardware stores. Open4cycle, if you read this do not post info if you are 100% positive of you answer to be true. Most all japanese cars have 1/8bspt threads. Even dare i say it, hondas to. The block you see can be unbolted. It connects the oil pressure switch and oil filter mount on one cast housing that is then bolted onto the engine. E-mail; if you have any other questions.

Post by **bleet** » Thu Apr 17, 2003 5:20 pm

silviaNE thanks for helping me out!

I will take you up on your offer to email you if I do need more help

Your newb, bleet.

Post by **Open4Cycle** » Thu Apr 17, 2003 5:20 pm

Hmm I'll check this out. I did screw a 1/8 NPT tubing adapter into mine. But I don't doubt they may use British Whitworth threads. Let me find my 55 deg center finder. I did count the threads per inch on the oil sender but its hard to measure thread pitch hear because your only checking 1/4 in of threads and the the difference of 1/8 NPT and 1/8 BPT is 27 and 28 TPI. Thank you for bringing this to my attention.

Post by **Open4Cycle** » Thu Apr 17, 2003 5:20 pm

Ok the results are in. I have in my right hand the oil filter housing that the oil pressure sending unit screws into. I have in my left hand one 1/8 27 NPT TAP. The tap screws in perfect. The threads of the tap and the sending unit fit together perfect with no daylight visible between them. My conclusion is 100% sure that the sending unit hole is 1/8 NPT! FYI this housing that I have in hand comes from a KA24E. I say I don't claim to be 100% correct on everything but if theres anything you need to know about threads and pipe just ask I been putting wrinkles on and in parts for over 20 years. Unified, International, British, ACME, Buttress, square, double E, Tripple E, and even threads that don't work.

Post by **Smebbin'd'240** » Thu Apr 17, 2003 5:20 pm

What I did was drill out the hole on the oil filter housing thing and tap the threads for my brass compression fitting. No "T" fitting. I used a mechanical gauge. I wanted reliablilty since I don't know if I can trust the electrical ones. I'm sure they are just as good. Used the water drian plug for my mech. water temp too on other side of the block. (KA-E btw)

Post by **DAEDALUS** » Thu Apr 17, 2003 5:20 pm

Hmm...I've wondered the same thing myself...about the size of the threads. I have a '90 Q45. I measured the oil pressure sensor and I thought it was 1/8NPT. So I tried screwing in my 1/8NPT oil pressure gauge hose, and it wouldn't quite go in. I pulled it off and compared the 2. The threads lined up perfectly, but the diameter of the tool was about .010" larger across the diameter at the leading face... I have no idea why. I ended up running the pressure gauge threads back and forth through an adapter fitting over and over, and this wore it down enough to where I could thread it into the block.

Post by **silviaNE** » Thu Apr 17, 2003 5:20 pm

trust me, do a search on this forum, you will find countless threads indicating 1/8 bstp. e-mail a moderator, they will tell you likewise. close dont count if you know what i mean.

Post by **1991240xs** » Thu Apr 17, 2003 5:20 pm

ya the reason yur 1/8 npt fits now is probably because you stripped the threads a little bit to your npt...nissan is bspt

Post by **Open4Cycle** » Thu Apr 17, 2003 5:20 pm

OK yall go ahead and think what you want! Have you screwed a 1/8 BPT in a oil filter housing of a KA24E with proper thread engagement yet?

Post by **Rownan** » Thu Apr 17, 2003 5:20 pm

The thread for the oil pressure sender is 1/8 BSPT. I had to use a 1/8 BSPT to 1/8 NPT adapter from autometer to hook up my oil pressure gauge. 1/8 NPT may screw in but the threading is BSPT, with NPT it may not seal properly.

And FYI you will not find any BSPT fittings in any hardware stores....

And forgot about the stock sending unit! You don't need it! If you are worries about the oil light being on constantly, it won't. With the stock sender removed, the oil light will NEVER come on.

Timhttp://www.projectaspec.com

Website · Post by **elbles** » Thu Apr 17, 2003 5:20 pm

Got another question about aftermarket oil pressure senders for everyone . . . regardless of thread size, what about the size of the senders themselves? I got a meter with an immemorable name from Levine Automotive, and the sending unit is so large, that once you add the adapter (BSPT->NPT), when installing the sender, it won't go in straight because it starts rubbing against the block (SOHC). I tried screwing the factory sender into the NPT side of the adapter, and it seemed to go just fine. Then, I went back to the car, and tried screwing the supposedly NPT sender into the supposedly BSPT block, and it seems to go fairly well, with little visible damage.

But, if this isn't the "best" way to do it, as I guess it isn't, what have you done to get an oversized sender to go in? Right angle adapter? Tubing based extension? I don't want to permenantly destroy the threads on my car, but from the comments above, it seems simple adapters are hard to find, I can't imagine what more complex ones would be like. Any and all suggestions would be helpful (I hope ;-)). Sorry for the long post . . .

Post by **Rownan** » Thu Apr 17, 2003 5:20 pm

As I said you will not find BSPT adapters in any hardware store but you WILL find NPT adapters! Go to home depot, they have a whole section of brass pipe fittings. Get yourself a right angle adapter and you're set to go. Be sure to use teflon tape.

Website · Post by **elbles** » Thu Apr 17, 2003 5:20 pm

Well, the sender that was supposedly NPT fit just fine in the hole/threads on the block. No leaks, gives an accurate reading. Used teflon tape. Unfortunately, the gauge is also confirming my fear of low oil pressure only at idle, and only at certain times, with no rhyme or reason to it. :-( My guess is the pump itself, or perhaps the pickup, but who knows . . . oh, and I'm sure the connection I have (NPT in BSPT) isn't the best, but until I see reason to switch, I'll continue being stupid. :-)

Post by **sil80drifter** » Thu Apr 17, 2003 5:20 pm

When you use a mechanical gauge in your SOHC 240, where in the firewall do you pull the oil line through, into the interior? On the passenger's side? Driver's side? Drill an extra hole and pull it through there? I am thinking of putting oil temp/pressure gauges into my 1990 240, and I don't now where to pull the lines through, because so far I've only pulled electrical cable, which it was ok to bend every which way. I'm assuming that you can't do that with oil lines.

sil80

Post by **Jookmasta** » Thu Apr 17, 2003 5:20 pm

Ok i am in the same dilemma with this oil pressure gauge installation. i have a 93 nissan 240sx with the KA24DE motor. i understand that the fitting wont go in the block b/c one is NPT and block is BSPT. i also notice that the sending unit that you pull out is sort of wedged at the end while the fitting that your putting in isnt. is it possible to duplicate the wedge like shape or should i go on the hunt for a BSPT adapter. Is there anywhere where i could get a BSPT adapter?????? Im tired of looking at a gauge that isnt hooked up. also is there any thoughts on the type of hose being used for this installation. I plan on using my plastic nylon one from autometer b/c they were the only one with a 12ft hose that could reach that end of the block. ive heard that the plastic isnt too durable but then again, i dont wanna spend eighty bucks on stainless steel braided hoses. ive heard about copper tubing, but i cant find any long enough. Help me please with the search for the secret BSPT adapter. thanks.

Post by **silviaNE** » Thu Apr 17, 2003 5:20 pm

You can find bstp to npt adapters in hardware stores, when i lived in chicago, i got them all the time. I am not talking about some home depot, but the old school mom and pop hardware stores. That the places to find the odd ball stuff. Sil80 you can use a lot of exsisting passages in the firewall. You can usually feed it through with the wiring. But it only takes a second to drill a hole and run a better/closer setup. If you are using that plastic capliary tubing make sure that your car dosent vibrate a lot or is near any sharp areas. I have seen that stuff crack a lot. If you have the money, upgrade to stainless an lines. It will handle all the pressure you will need for gauges, handle severe weather, not crack, and looks pimp to. I am happy to see that people are getting the fact that these threads are british and not national standard. When i first flamed this post, i never thoght it would cause this much debate.

Post by **silviaNE** » Thu Apr 17, 2003 5:20 pm

hey jookmasta you arent talking about pungie stakes are you?

Post by **Calvin** » Thu Apr 17, 2003 5:20 pm

If you are using an electric gauge, the weight of most aftermarket sending units combined with engine vibration can cause brass fittings to crack.

Here's a possible alternative:

http://www.nissport.com/catalo...-2100

Post by **silviaNE** » Thu Apr 17, 2003 5:20 pm

thats are very nice alt. But the price for an adapter is a little steep to me. You can make your own tee and adapters with earls fittings and save a few bucks. But if i had all the money in the world, i would buy it. It looks like a nice product.

Another oil pressure gauge thread -- factory sender thread size?

Another oil pressure gauge thread -- factory sender thread size?

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