So I finally got around to installing the greddy block adapter with my Oil temp & press sensors last night. I decided to tap them to NPT rather than buy an adapter. Got it all put together, everything nice and snug, did an oil change while I was at it. Had a buddy start the car and rev it a bit while I checked for leaks, there were none so I put up all the tools and went for a joy ride, everything still showed to be in order (idling at about 18-20PSI and 90-100PSI at full boost). Went out this morning to go pick somebody up and the oil pressure gauge's alarm started yelling at me, 0PSI on the gauge then comes the white smoke, hazards on immediately shut down the motor and pulled to the side and waited for the tow truck.

When I got it back to my house to investigate looks like the oil press sensor came out of the block adapter and proceded to give my car's undercarriage a bath in oil. Luckely the gauges did there job and I caught it before the motor ceased. Needless to say that the block adapter's in the trash now and I'm just gonna do it the way it's supposed to be done. Hopefully this serves as a warning to others getting ready to do the same thing.

 

if you're saying you tried to go from BPT to NPT by running a simple tap through the threads, one would expect it to not hold.

 

hold on im lost here. I have this adapter at home for my oil temp and pres gauge. it screws in where the filter screws in at and then the filter screws in after that. is that what you used that caused this???????

and what BPT and NPT.........sorry just tryin to not do what you did

 

He enlarged the holes to accommodate what fittings he had on hand and they didn't hold the fittings correctly.

 

we're about the only nation that uses NPT (national pipe thread). Most use BSP (British standard pipe) or otherwise known as BPT.

The size for most japanese sensors (like Greddy) is 1/8" BSP, but if you go to the local hardware store, your going to wind up getting 1/8" NPT fittings, as very few people carry the BSP fittings. The difference is, the 1/8" NPT has 27 threads per inch, the 1/8" BSP has 28 threads per inch. If you buy an american manufactured sensor, it's probably going to be 1/8" NPT threaded and not 1/8" BSP threaded.

If you muscle up on the 1/8" BSP sensor into the 1/8" NPT fitting, or vice versa, you can usually get it screwed in far enough to hold and not leak. Teflon tape will help. It's not right, and definitely not ideal, but it usually works. If you try to tap an 1/8" BSP to 1/8" NPT, you're going to wipe out most of the thread surface, and it's almost assured to eventually leak or blow the sensor out of the fitting.

Just make sure you know what threads are on the fitting and on the sensor and make sure they agree.

 

Rob, you have no worries.... your defi's use 1/8th npt and will work fine with that adapter.

you shouldnt retap the holes to get what you want with a product like that.... he should of either used the proper adapter, or went with a different form or gauge sensor install. Luckily, as he said, the gauge did what it was suppose to do. Proved my point as well as to why oil pressure and not egt is the more important of the 2 to be had.