1.8L oil pump fitment depending on year?
 

From what I had initially gathered, the 94-97 1.8L had the same oil pump but as I shop for oem oil pumps I noticed this one miata mecca sells has a note I haven't encountered before. It states the oil pump will work on 94-95 & 99-00 1.8L so it leaves me wondering what should i know about the 96-97 OEM oil pump part number? Does anyone know what makes the 96-97 fitment different? I have a motor from a 97'
https://cimg5.ibsrv.net/gimg/www.mia...090e53c129.jpg

They are interchangeable. #FakeNews

Hahah #fakenews thank you! Seems like such an odd note. I know the VVT NB motors have a different part number that's an updated higher pressure pump, but to my understanding even that is interchangeable on the non vvt BPs

Is it cause the threaded boss is different for the early obd2 crank sensor?

this is something I was not aware of messing with these earlier 1.8L I'm gonna have to try and get a side by side comparison to see if that's the cause it would make sense though

https://cimg1.ibsrv.net/gimg/www.mia...c8abdd7909.jpg
this Is the pump in question

Yeah isn’t it m5 instead of m6? Or offset differently? I remember having to modify the mount for an NB crank sensor.

I believe the OP housing has a stop feature for the sensor bracket in the later NA. BP does not have this. You.can see it between the mount hole and the timing wheel.

https://cimg0.ibsrv.net/gimg/www.mia...62e42311aa.jpg
https://cimg1.ibsrv.net/gimg/www.mia...86aed05008.jpg

I believe that the specs are 0.5 to 1.5 mm for the spacing between the sensor tip and the trigger wheel. Mine had an unstable signal at the credit card width so we used a feeler gauge with closer to 0.5 mm and the signal was all good after that. I may have bent the bracket out a smidgen to line the sensor tip up perfectly with the wheel.

VVT pump is higher volume, not pressure. Just for clarity.

I just checked the original oil pump that came off my '97 1.8 and what was reported previously is exactly correct. It appears the '96 and '97 oil pumps have a little metal nub as part of the casting where the crank sensor mounts to aid in aligning the little bracket the sensor is on. All the other year 1.8s appear to not have that metal nub in the casting.

From anyone elses experience is it alright to use one of the more common oil pumps sold that doesnt come with this extra casting to align the crank sensor so long as I take the step of using a feeler gauge to properly set the gap when I mount the sensor back or do I need to hunt down an identical oil pump with this casting?

Thank you for the clarification I appreciate all knowledge !

VVTs use higher VOLUME oil pumps not higher pressure as some third party websites advertise in their parts descriptions, noted!

Thank you sir for the pictures this is true

The 96 and 97 motors have a different cast oil pump because they're OBD2 and the OBD2 utilizes the crank position sensor. I am putting this engine into my 1990 NA6 Chassis with it's original NA6 harness which doesnt even have a crank position sensor anywhere on it therefore I ignore this sensor and different oil pump and use the regular oil pumps as I will be running off the CAS solely and not need this sensor?

Yes, the reason MiataMecca says the pump is compatible with pre-obdII long nose cars is that they use CAS.

MiataMecca probably has more experience with these cars than just about anyone. They put the disclaimer on there (and others don't) because they know more. They can be trusted as an authority.

thank you sir I see precisely what you mean I think it finally clicked in my head and it makes perfect sense why they would add that disclaimer for the more common folks replacing a OEM part on a 96/97 chassis with a stock ecu. I appreciate everyone's time and knowledge greatly thanks!