Oil pressure sending unit install
So the K20A2 only has an oil pressure switch sending unit, but I wanted to add an oil pressure gauge. I built my instrument cluster with a European oil pressure gauge instead of the voltmeter, so I picked up a Fiat sending unit to talk to it. This is how I added the Fiat sending unit to the Honda engine while retaining the stock oil pressure switch. I have seen a picture of a custom manifold that MWB made for one of their swaps and Tim (Fiat Monkey) told me that he made a manifold that was mounted in the trunk for his former K20 X.
I wanted to try and come up with a way to mount the Fiat sender on the engine. Here is a photo of the location I came up with.
This is the mount for the intermediate axle on the rear passenger side of the engine. There is an unused M8 threaded hole on the mount that was used to attach a heat shield in the RSX Type S, but the heat shield is deleted in the X swap as it would interfere with one of the subframe engine mounts.
Here is a picture of all of the parts I used on this project.
Top row (L to R): Fiat oil pressure gauge sending unit that has an M14 x 1.5 thread, an M14 x 1.5 to AN6 adapter, an AN6 to AN4 adapter.
Second row: 1/8” BPST oil pressure tee with an 1/8” NPT side port, Honda oil pressure switch.
Third row: hose clamp, custom mounting bracket made from aluminum stock, 1/8” NPT to AN4 adapter.
Bottom row: stainless braided hose with AN4 fittings.
Here is the sending unit mounted below the oil filter with the custom bracket I fabricated held with a hose clamp.
Here is what it looks like below the filter.
Here is the oil pressure tee with the side take off to go to the sending unit.
The stock oil pressure switch and the braided hose connected to the tee.
The final result with everything connected.
I am honestly not too thrilled with the hose clamp idea, but it is the best I could come up with. With everything connected it seems pretty solid. It all tucks nicely under the oil filter with plenty of clearance for the tripod CV joint. It seems to be well away from the heat of the exhaust header. The signal wire is run along the stock wiring harness up and along the top of the valve cover then eventually to a connector near the firewall where I will connect it to the car wiring harness.
One question I have that someone may be able to answer is what happens to the air that is in the hose and the adapters? Do I need to somehow try to fill the hose and sending unit with oil first or will it take care of itself once the engine is running?