question about oil filter adapter - 3000GT/Stealth International Message Center

bbak11010 · 06-03-2008, 03:32 PM

Hey guys,
I have two defi guages, oil pressure and temp.
I once bought an oil filter adapter but the thread does not fit my sensor.
Is there a thread adapter so that my smaller defi sensor can fit?
If not, where can I buy an oil filter that fits defi sensors?
I have a first gen VR4.
Thanks,

Dewman · 06-03-2008, 09:30 PM

hardware store?

Turbo Powered · 06-04-2008, 01:27 PM

It depends on what threads you have on the two parts you're trying to put together. The stock oil pressure sending unit has metric threads. You can buy an adapter from 3SX to convert it to 1/8" FNPT:

1/8-in NPT to Metric Adapter 2269*-*Mitsubishi 3000GT*/*Dodge Stealth

Most aftermarket sensors use NPT (National Pipe Thread) and most sandwich plate adapters also use NPT. If the need to fit your 1/8" MNPT (male NPT) sensor into a 1/4" FNPT (female NPT) port on the adapter, you can get what's called a reducing bushing (1/8" FNPT to 1/4" MNPT) from a hardware store.

tachyon_ftl · 06-04-2008, 08:06 PM

Actually, Turbo, that adapter is just backwards... it's to install a 1/8" NPT into our block. Our block is "BSPT," and therein hangs a tale...

bbak, to try and cut a long story short our block and the Defi are not actually "metric." Our block is BSPT- British Standard Pipe Thread. Some Japanese companies, Greddy for example (I know because I have Greddy) use BSPT. BSPT is the Brit version of NPT. It's the same idea as NPT- a tapered end with threads cut into it. The taper helps seal the connection, whereas normal straight threads of any kind, SAE or Metric, do not.

The issue you're probably having is that your Defi sensors won't fit the holes in your sandwich plate. They're close, because most car sensors use a 1/8" fitting, but the thread count is off by 1 and the taper is 5 deg different. Some peeps jam them in anyway, but that is not recommended.

1/8" NPT is 27 threads per inch, 1/8 BSPT is 28 threads per inch. The tapers are 50 deg and 55 deg, but I forget which is which.

It turns out that while there are a few adapters to put a 1/8" NPT into the 1/8" BSPT, there are none to speak of to go the other way. Why, I don't know. I looked pretty hard; I'm an automation engineer, and I checked industrial supply companies as well as car companies. No luck. The way that I ultimately did it was to plug the three holes in the sandwich plate with 1/8" NPT pipe plugs, then drill and tap a new hole for my Greddy oil pressure gauge. This is actually not too hard. My Sears Craftsman tap set actually has a 1/8" BSPT tap, and an aluminum sandwich plate is easy to work. The tap you might find at a hardware store, or you could order it from McMaster-Carr at McMaster-Carr

What was harder was drilling and tapping the banjo bolt on top of the fuel filter for my fuel pressure gauge, but it just fits and that worked really well too.

If you can find or order a blank sandwich plate, that would be great. If not, just drill a couple more holes in the one you've got and use them.

Turbo Powered · 06-04-2008, 08:44 PM

I also use instrumentation fittings all the time and have spec'd BSPT fittings for transducers that came with them. I had heard that BSPT threads would seal into NPT threads, I just didn't realize I had already done it! I installed Greddy EGT and FP sensors into 1/8" FNPT fittings and they both sealed fine! I'm pretty anal, if I knew the sensors were BSPT I would have found or made adapters with those threads.

bbak said he was looking for an adapter so his "small defi sensor" can fit. I don't think he would have noticed the difference between 27 and 28 threads per inch, and they're both almost exactly the same diameter. I think he is looking at some different combo of threads on his sensor and sandwich plate.

tachyon_ftl · 06-05-2008, 04:53 AM

Quote:

bbak said he was looking for an adapter so his "small defi sensor" can fit. I don't think he would have noticed the difference between 27 and 28 threads per inch, and they're both almost exactly the same diameter. I think he is looking at some different combo of threads on his sensor and sandwich plate.

Yeah, I don't know what the fittings are on Defi but I thought they were 1/8" BSPT. bbak, when you say they won't fit, is it that it won't thread in or is the hole in the adapter is way to big- say 1/4" not 1/8"?

Like Turbo said, you can get adapters to go from 1/4" to 1/8"- that's easy- but see what you can find out on the Defi fittings, I thought that they were 1/8" BSPT. If it's just going from 1/4" to 1/8" NPT, that's called a reducing bushing and any big hardware store (note: Lowes and Home Depot are not hardware stores) will have them.

06-03-2008, 03:32 PM	#1 (permalink)
bbak11010 Forum Member Join Date: Dec 2006 Location: henrico, va Drives: 92 VR4 Trader Rating: (7)	question about oil filter adapter Hey guys, I have two defi guages, oil pressure and temp. I once bought an oil filter adapter but the thread does not fit my sensor. Is there a thread adapter so that my smaller defi sensor can fit? If not, where can I buy an oil filter that fits defi sensors? I have a first gen VR4. Thanks,

06-03-2008, 09:30 PM	#2 (permalink)
Dewman Verified Seller Join Date: Sep 2005 Location: Midland, MI Drives: '00 Camaro z28 Trader Rating: (9)	Re: question about oil filter adapter hardware store? __________________ 2000 Camaro z28 Stealth sold

06-04-2008, 01:27 PM	#3 (permalink)
Turbo Powered modding addicted Join Date: Nov 2003 Location: PA Drives: at high g's Trader Rating: (23)	Re: question about oil filter adapter It depends on what threads you have on the two parts you're trying to put together. The stock oil pressure sending unit has metric threads. You can buy an adapter from 3SX to convert it to 1/8" FNPT: 1/8-in NPT to Metric Adapter 2269-Mitsubishi 3000GT/Dodge Stealth Most aftermarket sensors use NPT (National Pipe Thread) and most sandwich plate adapters also use NPT. If the need to fit your 1/8" MNPT (male NPT) sensor into a 1/4" FNPT (female NPT) port on the adapter, you can get what's called a reducing bushing (1/8" FNPT to 1/4" MNPT) from a hardware store. __________________

06-04-2008, 08:06 PM	#4 (permalink)
tachyon_ftl '96 VR4 Join Date: Apr 2004 Location: Hollis, NH Drives: It's spos'd to move? Trader Rating: (12)	Re: question about oil filter adapter Actually, Turbo, that adapter is just backwards... it's to install a 1/8" NPT into our block. Our block is "BSPT," and therein hangs a tale... bbak, to try and cut a long story short our block and the Defi are not actually "metric." Our block is BSPT- British Standard Pipe Thread. Some Japanese companies, Greddy for example (I know because I have Greddy) use BSPT. BSPT is the Brit version of NPT. It's the same idea as NPT- a tapered end with threads cut into it. The taper helps seal the connection, whereas normal straight threads of any kind, SAE or Metric, do not. The issue you're probably having is that your Defi sensors won't fit the holes in your sandwich plate. They're close, because most car sensors use a 1/8" fitting, but the thread count is off by 1 and the taper is 5 deg different. Some peeps jam them in anyway, but that is not recommended. 1/8" NPT is 27 threads per inch, 1/8 BSPT is 28 threads per inch. The tapers are 50 deg and 55 deg, but I forget which is which. It turns out that while there are a few adapters to put a 1/8" NPT into the 1/8" BSPT, there are none to speak of to go the other way. Why, I don't know. I looked pretty hard; I'm an automation engineer, and I checked industrial supply companies as well as car companies. No luck. The way that I ultimately did it was to plug the three holes in the sandwich plate with 1/8" NPT pipe plugs, then drill and tap a new hole for my Greddy oil pressure gauge. This is actually not too hard. My Sears Craftsman tap set actually has a 1/8" BSPT tap, and an aluminum sandwich plate is easy to work. The tap you might find at a hardware store, or you could order it from McMaster-Carr at McMaster-Carr What was harder was drilling and tapping the banjo bolt on top of the fuel filter for my fuel pressure gauge, but it just fits and that worked really well too. If you can find or order a blank sandwich plate, that would be great. If not, just drill a couple more holes in the one you've got and use them. __________________ GHOST - "Because it's white and it tends to vanish" K&N FIPK, DSM Sidemounts, Hotwired Walbro, EK2 Fuel Loop & AEM AFPR, "The Only Known Dr. Stupid 3in SS DP in Captivity!", Random Tech 3in Cat, Borla Catback, Greddy TT and EBC, Greddy Boost, Oil Prs and Fuel Prs in Cianci 3 Up Pillar Pod, Tein S-Techs, Bilstein Struts, Maximal Control Arms, Carbotech Rotors/Pads and StopTech SS Brake Lines. In work- 450CC DSM Injectors and SAFC-2

06-04-2008, 08:44 PM	#5 (permalink)
Turbo Powered modding addicted Join Date: Nov 2003 Location: PA Drives: at high g's Trader Rating: (23)	Re: question about oil filter adapter I also use instrumentation fittings all the time and have spec'd BSPT fittings for transducers that came with them. I had heard that BSPT threads would seal into NPT threads, I just didn't realize I had already done it! I installed Greddy EGT and FP sensors into 1/8" FNPT fittings and they both sealed fine! I'm pretty anal, if I knew the sensors were BSPT I would have found or made adapters with those threads. bbak said he was looking for an adapter so his "small defi sensor" can fit. I don't think he would have noticed the difference between 27 and 28 threads per inch, and they're both almost exactly the same diameter. I think he is looking at some different combo of threads on his sensor and sandwich plate.

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