Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Oil pressure disaster

Katanazz,

My S2 Roadster runs within the parameters you mentioned when hot usually around 2 +bar at about 2000 rpm then down to about 1 bar when stationary. However I did get a strange reading when away with friends, the first time the car had been outdoors overnight and subject to morning dew, dripping thru the bonnet louvres. Set off home everything fine, then after being in heavy crawling traffic for a while I had to brake sharp to avoid an idiot trying to take the front of my car off at an island. My oil pressure immediately feel to almost zero. I pulled over checked everything was fine but the oil pressure reading didn't rise much above one bar, we were heading to Malvern anyway so I thought get checked out at service dept. Travelled about 20 miles, water temp quite normal went down a long steep hill and my oil pressure started to read normally for the rest of the journey to Malvern. Spoke with the Service Manager, he first comment was that the sender and registers are not particularly reliable and/or accurate, he tested the sender with the ignition on and said I needed to keep an eye on it as it may be on the way out. Got me home fine with normal readings.

However, I noted when I washed the car that day and lifted the bonnet I could see water had collected on the oil sender wire bridging across it. What I think may have happened when I got the low reading immediately after braking hard that the morning dew water may moved across the sender wire and then when I went down long steep hill it cleared the water from the sender. Pure guess work on my part, as I would have expected a short but the wire has a plastic shield. I am taking the Morgan Service Manager's advice and monitoring the readings as the sender or the oil pressure gauge may be on their way out, I will be getting the oil sender replaced when I get my radiator sorted shortly.

Many thanks for that helpful piece of physics. Also for the other experiences shared in this thread. I did finally locate some figures on p41 of the Manual, hidden-away in "Instruments" rather than engine characteristics. So it looks like we are all OK. But do any Morgans actually have an oil pressure as high as 7bar ? If not then why fit such a gauge, which means that the critical measurement as the needle drops from 1bar to 0.7bar is an arc about 1mm long !

Faults can cause over high oil pressure on engines .... stuck pressure relief valve, blockage of oilways etc .... and that's not good either ..... so I guess knowing when it's too high is a valid diagnostic function of the gauge as well as the more normal too low indication.

K

The cynical side of me suggests it was the only pressure range now available in that series of Smiths triple gauge.

Yay, cynicism rules !

I wonder if it's a 'symmetry' kind of thing? Although mine is a lot older - when under normal running, the oil pressure needle is pretty central, the ammeter needle is central and the water temp needle is central.

If standard running oil pressure for yours in 2-4 bar, again, the needle would be 'central -ish' at just over 3 bar.

And in racing and flying they would sometimes turn the gauges so when everything was normal the needles were all vertical .... all it took was a quick flick of the eyes across the dash to spot any needle out of line that might need more attention .... probably overkill for a touring holiday in Yorkshire though 🙂

K

On first start up, my oil pressure is around 6 bar, maybe a little more. It'll occasionally dart up briefly to 8 bar till till it's fully warmed up. I just put that down to a morgan quirk.