803cc oil pressure

[JOWETTJAVELIN]

Hi all, just fitted a brand new Smiths oil pressure gauge to my 803 and here are the readings:

starting from cold 65-70psi
when hot running in top gear 37-44psi
and (the reason why I fitted it) 8-12psi at idle when hot. Idling speed is satisfactory.

On the road in the lower gears it seems a trifle low to me (but I don't know much apart from it shouldn't be below 40psi when above 30mph in top gear).

Duckham's 20w50 oil used.
Engine has covered 39,000 miles and is original 803cc.

My main concern is the low pressure at idle. There are no rumblings or any worrying noises from the engine and no smoke etc. I haven't had the sump off yet to examine/clean the oil strainer and pressure release valve.

So, are these readings anything to be concerned about? I don't want to be tinkering with anything that doesn't need it...

[bmcecosse]

For an 803 - they will be fine. It's not exactly a racing engine! That engine has a particularly hopeless oil pump with sliding vanes. Don't worry about it - it's got a long life ahead .

[JOWETTJAVELIN]

Thanks for that BMC - I was particulary worried at the idling figure. I am much, much younger than the car in question, so therefore relatively inexperienced in such matters.

The car sounds fine and had I not fitted the gauge I wouldn't have had anything to worry about whilst actually driving... ho hum

Just that pesky warning lamp flicker at idle...

[mike.perry]

My 1275 warning light comes on steady at 30mph in top after a run down the motorway, it has done for years. The gauge shows 20psi. No need to panic yet.

[bmcecosse]

That's certainly not good for a 1275 ........

[David53]

Those figures do sound a little low....I only have the original Oil Pressure Gauge fitted (MM style dash) which has segments in 20's going up to 80's so not terribly accurate. However, I have to assume the gauge is at least indicative of the pressure. My figures are:

Cold Start: 65
Running at full speed top gear once hot: 55-60
Sitting at lights idling once hot: 20

[bmcecosse]

Yes - the 803 pressures from JJ are low - but not dangerously so. Maybe your engine has been rebuilt with a decent oil pump at some time David! The 1275 readings from MP however are to my mind very definitely in the dangerously low category......

[JOWETTJAVELIN]

Gave it a blast on the motorway today to road test the car. Showed decent pressure when up at high speed (well, 55 MPH anyway) but when I stopped the warning lamp was well aglow at idle and the gauge was showing little above 0 lb/psi... odd indeed but there are no noises etc to suggest anything is amiss.
At the next service I will drop the sump and have a look if the relief valve is blocked or the oil strainer clogged... and fit a magnetic sump plug whilst I'm at it.

[bmcecosse]

It's just a bit worn -don't worry about it too much. I assume you have 20W50 in there - I think someone makes 20W60 -may be worth a turn. And of course some swear by a can of STP in the engine.