Oil pressure gauge fitting
 

I've always been a little paranoid about my oil pressure. It is fine at cold start, 30psi idle, 60'ish by about 3000rpm, but then falls once fully warmed up to about 20psi idle and 35 to 40psi by 4000rpm. This is on the stock OEM gauge.

So I want to fit a more accurate gauge to check on it, a dual pressure and temperature gauge such as here . Can someone tell me what the engine block fitting/thread specs are of the OEM sender?

I have an FM twincooler with sandwich plate style thermostat for the oil cooler. I'd like to keep the OEM gauge functional if possible, does anyone have a neat solution for sourcing the oil pressure and temperature signal for the new gauge other than at the OEM point (which is already 'T'd to supply oil to the turbo)?

just fwiw:

manual says @ 1000rpm - 28-43psi
@ 3000rpm - 43-57psi

1/8" BSP taper.

Here is an adapter that goes from BSP male to NPT female, allowing the stock sensor to be replaced with an aftermarket unit.

Here is one that goes from BSP male to 2x NPT female, allowing both an aftermarket sensor and a turbo feed takeoff.

Somewhere out there is one with BSP male to NPT & BSP female, allowing both the stock sensor and an aftermarket sensor, though I can't find it at the moment.

Thanks for the info. Any thoughts on the temp sensor? I have an excessive need for 4 sources, one for the OEM sensor, one for the new sensor, one for the new sensors temp sender and one for the turbo oil line.

I had thought about a sandwich plate with pre-drilled fittings but as far as I can see no one makes a thermostat version of one (there would also be the issue of lack of room for the sensors that close to the block).

OK I think I have a simple solution. What do you all think of installing this adaptor under the present thermostatic sandwich plate?

Any "gotcha's" to the idea of doubling up the 2 sandwich plates?

Easiest oil temp sender is what I did. I glued a "bulb" type sender to the rear of my oil pan.

One last question, before I order up the guage above tomorrow. Does anyone have an alternative, similarly accurate and of good quality, dual analogue gauge suggestion? The SPA gauges are excellent but I prefer analogue gauges rather than digital - if not white with blue lighting will get ordered tomorrow.

Thanks!

I should learn to never say "one last question", I have another.

I've recently seen a gauge mount that is a single stainless steel band, looked functional as well cool IMO, and the gauge I'm looking at is only 22mm deep. I can't find damn thing now. Anyone have a link to it or something similar?

OK, I have the sandwich plate. Nice piece with 4 convenient 1/8 NPT ports.

However I've been thinking about its location and, more importantly, the location that means for the sender ports. Looking at the Mazda oil flow diagram the ports tap into the oil system pre-filter and pre-cooler, so not ideal for the oil pressure sensor location and I'm also uneasy about tapping pre-filtered oil from it for the turbo.

What do you all think? Have I got the oil flow right (filtered oil down the centre pipe)? If so the new pressure sender will need to replace the OEM one on the block (and that move to the new sandwich plate - if there is room for such a large sender). What to do with the turbo oil feed, pre-filtered oil really a concern?