Oil Pressure Sending Unit

[eric s]

Does anybody know what size threads is on the block of a 91 prelude B20A5 where the oil pressure sending unit screws into the block i am trying to hook up a aftermarket mechanical oil pressure gauge i know the type of adapter i need is like a T-Fitting where you have a spot for your oil feed line and another spot for your oil pressure sending unit to screw into and then the other part is an extension that screws into the block but i dont know what size threads they are and whether they are metric or standard threads i tried 1/8 NPT and it would go into the block but i could not get the threads started nor could i get the oil pressure sending unit to screw into the adapter PLEASE HELP!!!!!!!

 

[K2e2vin]

I'd assume it's 1/8 BSP The 1/8NPT looks about the same right? The BSP fittings have the same thread count, etc. but the thread designs are a little different(different angle and BSP is more rounded compared to NPT).

 

[eric s]

I'm not sure how many mms that is in metric size somebody told me 10mm but im not sure is this what size threads i need

 

[K2e2vin]

I haven't specifically looked at the B20As, but in other Honda's it's definitely 1/8 BSPT, not metric. It'll actually tell you in the Helms manual.

 

[eric s]

I did some research to find out what size in bsp is equal to npt and it says 10.3mm for milimeters would this be correct

 

[K2e2vin]

The BSPT sizes are equivilent to NPT, but the thread design is different. BSPT is more rounded than NPT along with different thread angle(IIRC, 55 vs. 60).

Metric fittings are usually just 10mm or 12mm, compared to BSPT/NPT they're fine-thread.