Rb30 oil pressure switch and sender. Replace or modify.

[mudnut]

G'day, all. My oil pressure gauge has been on the Fritz, and I am thinking of upgrading to an after market one. I have tried a few searches, but not much has been written about it. The problem is that the RB30 uses a combined switch/sender, so that the fuel pump runs once the oil pressure rises. I don't particularly want to fit a T piece to accomodate the two systems, but will if it is the only option. Has anyone fitted a good after market set up, and/or could recommend a good system? Cheers.

[the evil twin]

Yeah, known problem those 3 litre senders eh.
I replaced mine on the Skyline with OEM just to save the hass.
I wonder if they are cheaper from Holden or a Holden orientated spares outlet for a VL one

[mudnut]

I have found switches to fit VLs but not both. I'm not real keen on piping oil into the cab either. So electronic is the go.

[mudnut]

This maybe??? http://vwparts.aircooled.net/VDO-80psi-Oil-Pressure-Sending-Unit-1-8-27-NPTF-p/v360009.htm

[dom14]

G'day, all. My oil pressure gauge has been on the Fritz, and I am thinking of upgrading to an after market one. I have tried a few searches, but not much has been written about it. The problem is that the RB30 uses a combined switch/sender, so that the fuel pump runs once the oil pressure rises. I don't particularly want to fit a T piece to accomodate the two systems, but will if it is the only option. Has anyone fitted a good after market set up, and/or could recommend a good system? Cheers.

Read this, if you wanna fix the existing sender, but ignore all the dismantling stuff I did to the sender unit.
You only need to unclog the oil hole of the sender via a combination of solvent, high pressure spray, vacuum, etc.

Do not use the silly pipe wrench method of undoing the sender which I did. Curved 17mm spanner is the way to go.

http://www.nissanpatrol.com.au/forums/showthread.php?35521-Oil-Pressure-Sender-Repair-RB30-Patrol

Remember the oil pressure sender thread is tapered or in other words the it's angled. In other words diameter at the base of sender unit thread is slightly higher than than the diameter at the tip.
So, when you buy the after market kit, you need to make sure you buy the right thread(pitch, angle and diameter) or use an adapter from Pirtek, etc.(Canterbury road, Bayswater).
Last thing you wanna do is to accidentally damage the oil pressure sender hole thread of the engine block.

If I remember correctly, it's NPT 3/8", but tapered.

Any of these fleabay kits should work. You just need the correct adapter for the sender, 'cos most of these aftermarket sender thread is not tapered(if I'm correct about that).

http://www.ebay.com.au/itm/2-52mm-DIGITAL-LED-OIL-TEMP-PRESSURE-METER-GAUGE-WITH-SENSOR-CAR-AUTO-0-100-PSI-/131257943395?hash=item1e8f954563:g:0DAAAOSwxCxT2zs F

http://www.ebay.com.au/itm/CAR-Vehicle-2-52mm-OIL-PRESSURE-PRESS-METER-Pointer-GAUGE-AU-/331207403227?hash=item4d1d7fe6db:g:pOcAAOxyRhBSs69 H

Also, in RB30 Patrol, oil pressure sender body is the earth. So, the earthing happens via thread part of the sender touching engine block. So, if you use teflon tape on the thread, use only a little bit of it, or use a separate earth wire wrapped around the body of the sender or something similar. I used teflon, but it hasn't caused a weak earth connection in my case, but I think it's possible with too much teflon tape. Improving the earth with a separate wire to the body of the sender is a good approach IMO.

[mudnut]

Cheers, Dom. I have read your excellent write up about the sender. I will try the quick fix, but I think the problem is to do with the wiring or gauge.

[dom14]

Cheers, Dom. I have read your excellent write up about the sender. I will try the quick fix, but I think the problem is to do with the wiring or gauge.

Hi Craig,

Cool. If the gauge is faulty, of course you're better off with an aftermarket kit.
They are too cheap on ebay and easy to install as well.
I used an adapter from Pirtek(to match the tapered thread) initially.
That because I plugged the original sender hole on the block with that adapter and a plug and
used a sandwich plate that I fitted on to the oil filter while I was fixing and testing the sender.

BTW, oil pressure sender( pressure switch wire from memory ) is connected to the Fuel pump Control Unit(just under fuse board).
Fuel pump won't work if you simply disconnect the stock fuel pressure sender, unless of course you bypass the Fuel Pump Control Unit & directly wire the power to the Fuel Pump.
From memory, it's fuel pressure switch wire that's connected to the Fuel Pump Control Unit, not the fuel pressure sender wire.
It's the fuel pressure sender part of the sender unit that usually becomes faulty due getting clogged up with bit of oil gunk over the years. Fuel pressure switch still works fine from what I've seen and heard so far.
Perhaps better to leave it as it is, and use a sandwich plate to install the new aftermarket kit.
In mine, I still have the sandwich plate fitted, but I haven't got around to install the aftermarket oil pressure kit yet.
Sandwich plate only cost me around $20 including postage from China & it's available locally fro $30 or so.
It's a universal sandwich plate kit, so you can use the matching bits to suit the RB30 oil filter.

http://www.ebay.com.au/itm/UNIVERSAL-OIL-COOLER-ADAPTOR-ENGINE-BLOCK-FILTER-SANDWICH-PLATE-AN10-ALLOY-/321362797677?hash=item4ad2b7246d:g:N0kAAMXQeKNTM5l L

http://www.ebay.com.au/itm/Oil-filter-sandwich-plate-adapter-pressure-temp-sensor-Nissan-Silvia-Skyline-/151003886584?hash=item23288873f8:g:NOAAAOSwLnlWnV8 j

Cheers
Dom

[dom14]

Yeah, known problem those 3 litre senders eh.
I replaced mine on the Skyline with OEM just to save the hass.
I wonder if they are cheaper from Holden or a Holden orientated spares outlet for a VL one

VL or Skyline oil pressure sender is not compatible with the RB30 Patrol one.
I found that out the hard way. But, Yendor(Rodney) already advised me they weren't compatible while I was fiddling with a Skyline one.
I being myself, had to learn it the hard way. :D

[mudnut]

That plate looks is great as it allows you to keep the circuit that kills the engine if oil pressure is too low. I suppose if you run a good sender and gauge, there would be an indication if the pressure went south anyway. I was thinking of fitting a prelube cylinder as my Patrol can sit for a week or more before I start it, and the plate would allow that too.

[dom14]

That plate looks is great as it allows you to keep the circuit that kills the engine if oil pressure is too low. I suppose if you run a good sender and gauge, there would be an indication if the pressure went south anyway. I was thinking of fitting a prelube cylinder as my Patrol can sit for a week or more before I start it, and the plate would allow that too.

What is a "prelube cylinder"?

How does the faulty oil pressure gauge manifest in your case?
Does the dial move at all? Or is it flickering?

This is how I understood the mechanism of the Fuel Pump Control Unit.
Fuel Pump Control unit has a circuit that "primes" the fuel pump to get the car started.
So, once you've turned the ignition on, fuel pump keeps running until you start the car.
At least that's how it operates in mine.
Once you've started the car, alternator power takes over the powering of the fuel pump via
the switching mechanism in the Fuel Pump Control Unit, which gets activated by the oil pressure.
When I stop the engine, that in turn disconnects the power to the fuel pump, simply because I turn the ignition off
to stop the engine.
But, if you stop the engine without turning the ignition off(lets say via pulling ignition wire or stalling the engine), then
the fuel pump stops because the power to the fuel pump is provided via the oil pressure activated power switching
from the Fuel Pump Control Unit.
I can't say for sure whether the alternator powers the fuel pump directly while the engine is running, but it appears the alternator power is involved because there is an alternator power line goes into the Fuel Pump Control Unit(white wire).
Regardless of that, I think that's the safety mechanism the Fuel Pump Control Unit offer in RB30 Patrol.
It comes handy when you have an accident, so the fuel pump won't keep pumping petrol when the engine has stopped.
Kinda make sense 'cos last thing you need a crashed car is the fuel pump to keep running.
Since they RB30 Patrol always come with electric fuel pump, that safety mechanism of the Fuel Pump Control Unit makes sense to me. If the fuel pump is mechanical like in TB42, that safety switching mechanism of the RB30 Patrol Fuel Pump Control Unit won't be necessary.

I don't think RB30 Patrol Fuel Pump Control Unit has a safety mechanism to cut the fuel of a running engine when the oil pressure drops due to low oil
In other words, low oil engine will end up ceasing the engine in RB30, just as many other cars.

Let me know if I'm wrong about the above.

My next project is actually to wire either the aftermarket oil pressure gauge kit or the stock oil pressure sender, so it actually idiot proofs the safety of the engine in case of oil level goes low or a sudden oil leak occurs. I'm not sure whether that can be achieved by fiddling with the oil pressure switch wire of the sender unit, 'cos it's also connected with the Fuel Pump Control unit to provide the above safety mechanism in case of an accident. But, I will give it a go and see whether it works(I doubt it though). If not, I will use the aftermarket oil pressure gauge kit or even a separate oil pressure switch to achieve that.
The above sandwich plate allows that, 'cos it has two threaded holes for two sensor/sender units.

My project idea might sound like an overkill. But, it can come handy when we go for long trips and rarely remember to keep looking at the oil pressure gauge or dashboard oil pressure warning light due to excitement of the trip. :)

[dom14]

Found some information on prelubing here.
Thanx for the idea Craig.

http://www.crankshaftcoalition.com/wiki/How_to_prep_and_start_a_rebuilt_engine

[mudnut]

This is the system I was looking at. Fairly simple http://www.engineprelube.com/.

I am hoping that the switch acts as a safeguard as well.

[dom14]

This is the system I was looking at. Fairly simple http://www.engineprelube.com/.

The RB30 doesn't have a fuel system failure protection other than the engine stalling when fuel in the carby runs out.

Sorry, sometime I use "fuel pressure" instead of "oil pressure" when I write. I just corrected it in my previous post.
I meant "oil pressure failure safety mechanism".
The idea is the engine shuts when oil pressure drops too low, probably not the way it should happen.
I'm thinking of "Low oil pressure alarm", which I already have all the gear for.
Just haven't got around to install it and wire it.

The main function of the RB30 Patrol "Fuel Pump Control Unit"(or the only function) as I understand is to cut off the power to fuel pump in case engine stops while the ignition is on, as it would happen in an accident. It basically achieves that by wiring the fuel pump control unit in series with the Low Oil Pressure Switch, which in case of RB30 is the oil pressure sender as well

I hope I'm right about that.

[mudnut]

I've edited my post, accordingly.

[dom14]

I've edited my post, accordingly.

Let me know once you finished the installation of the prelube cylinder unit.
I'm very much interested in it, and hoping to install a one in my troll as well.
It would be great if you can document the process and post it here.
Cheers

[mudnut]

It will be a long wait, as I still want a snorkel, and I've been trying to save since the day I got the car. The good thing about the Pre-lube is that it can be stripped and fitted to the next car.