Member Since: 21 Oct 2016
Location: kent
Posts: 13669
Oil pressure switch
Hi
Currently sorting out bits to fit an oil pressure switch gauge , however Am I missing something here please as this doesn’t make sense
the current oil pressure switch is rated at 0.3 bar ,
According to the workshop manual The bare Min the oil pressure should be
min of 0.50 bar (7.25 psi) at idle
1.0 bar (14.5 psi) @ and above 2,500 revs
What I didn’t understand is why the current oil pressure switch is rated below the bare minimum , surely it should be at least above 0.50 bar to give an earlier warning of low oil pressure
Therefore by having a higher rated oil pressure switch it should give an earlier warning of any issues
Many thks as always listening to me rattle on
24th Oct 2019 11:45 am
Gareth Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26704
You might be better taking a feed from elsewhere. I have seen a post from Oval that says they measure at different points in the system. There could be differences is the reference pressure before and after the filter for example, and you don’t know where your quoted figures are achieved?
24th Oct 2019 12:06 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10368
You don't care what the pressure is before the filter, you want to know what is distributed to the engine.
The LR possition on the head gives what I consider a worse case reading. Although Oval autos can of course correct me.
The figures given, are to give the engine a clean bill of health.
Where as a worn and/or hot engine may have lower figures, so they don't want to worry the driver too much! or unnecessary, particularly when they don't have a gauge fitted.
I have known some pressure switches (rare beasts) (when fitted with a gauge) have a 2 stage light, bright, and less bright!
24th Oct 2019 12:09 pm
OvalAutos
Member Since: 28 Dec 2018
Location: Cradley Heath
Posts: 382
The location of the sensor on the head is at the end of the oil gallery. Therefore it is the where the pressure would be the least after feeding the bearings, lifters and cam chains.
When we've done a full measure on a test engine, we've put sensors on the pump, after the filter (on the housing), the normal pressure switch on the left head and tapped in to the end of the gallery on the right head.
What was observed (when hot, 2500rpm) is that there is a drop of between 1 to 1.5 bar from the pump to the end measurement points on a fresh engine. On a worn engine, the drop was ~2.2 bar. We also experimented with a used (12k) filter & a new one and there was not much in it.
Our normal test is just at the filter (after) and the original head location. We look for around 1 bar at idle when hot in the left head on our engines.
I would say that if the standard pressure sensor oil light starts to flicker at idle, then its time to find out why. If it comes on while driving (higher revs), then you've got a serious problem about to happen.Joe
24th Oct 2019 12:37 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13669
Thks a million gents taking the time to kindly explaining it for me and that now makes a lot of sense
Where are the other places that I can easily fit an oil pressure gauge adaptor Plse , which would then allow me to leave the original oil pressure switch alone ,
if I did unscrew the original oil pressure switch and fit the short stainless steel aeroquip style hose can that effect the pressure or wouldn’t It make any difference
Ideally would prefer to fit the pressure gauge elsewhere and leave the original pressure switch alone , just don’t know where the alternative places are plse
Do apologise asking the daft questions and really am so grateful for ur patience with me asking
Thks a million once again
Ps, enclosed the links of the pressure gauges I’ve found
Member Since: 03 Nov 2009
Location: Greater Venice
Posts: 2025
The female threaded hole on the head of our V6 is NPT 1/4 18G NOT M14x1,5 as I saw in different forums. Checked personaly with thread counter!!!!
Pay attention to this, they are very similar to each other and M14x1.5 male thread is screwed onto the female NPT 1/4 18G thread but obviously tends to ruin the thread, especially at the end, when it is tightened.
Member Since: 21 Oct 2016
Location: kent
Posts: 13669
dgardel wrote:
Same project for me with same LCD pressure gauge and V8 switch.
Brilliant , just looking for the sensor now
Great that u noticed and shame then many sites displaying the wrong information , with the new sensor I’ll be able to test the other 2 x connections on the adaptor
Thks again
25th Aug 2020 10:57 am
dgardel
Member Since: 03 Nov 2009
Location: Greater Venice
Posts: 2025
gstuart wrote:
............
Cut the monitor into a dashboard panel for now , will do the rest at some stage
...........
I think for the moment I'll put the gauge inside the glove compartment............Discovery 5 tdv6 HSE Corris Gray Outback Engineering Limited Edition IID Pro MV License
25th Aug 2020 11:13 am
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13669
Found one
Thks so much as indeed saved a lot of messing around
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