Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Oil Pressure at 1 bar. Is this too low?

Hi Guys,

I've been using my dad's Morgan again, what a joy! But I'm concerned about the oil pressure which is at 1 bar on tick over when the engine is up to temperature. Seems very low say compared to my 4 litre Jeep that ticks over at over 2 on idle.

Dad's Mog is an 07 plate 3 litre V6 Roadster. Does anyone have any idea if this is normal?

Any help gratefully received.

Yes but he can pick up the bills!!

Not being an expert, I would have thought 1 bar was OK at tickover, as the engine is under very little load. I'd expect to see at least 3 or 4 bar with everything hot, when driving at speed.
Gerry.

Just had a look at the MOG multi model handbook. It warns that oil pressure should not drop below 0.7 bar in any model. I would have it checked if only for peace of mind.

Andy

Depends on the engine. Different engines are happy with quite different figures. So although other engine stuff is interesting, check with manufacturer.

The standard pressure switch for the light is often too low a figure as if it lights when the engine is being driven - the damage has already been done. I think the standard pressure switch on a crossflow is 7psi, but I used to use a 25 psi one, along with a high flow pump - impeller approx double sized. I replaced two switches on an Austin Maxi as they both failed the same way - started to light at higher quite ok pressures.

Some engines though have very different figures, the Austin Seven gauge if it gets to 7 psi, you have to stop and clean things as it means the system is becoming blocked - a nice low pressure is what you want!

Don't know who said it, but an oil pressure gauge merely tells one the pressure of the oil that isn't circulating!

1 bar by the way is near as makes no odds, 14.5 psi if you live in the past like I do.

Depends on the oil and filter. Roadsters do vary with temperature. I was concerned about low idle pressure last time it was hot (2011), so switched to Mobil 1 0-40 I think (without checking) - definitely zero grade cold. This made a big difference, especially when cold. So now when the oil is warm but not hot I get 4+ bar at speed and 2+ bar at idle. But as soon as the oil is worked hard, the 'at speed' drops to 3 bar, and idle is a shade under 2bar. I know a lubrication expert from my MG days and had a long exchange with him, because the recommended grade in the handbook is not the same as for the Mondeo ST220. At the time I didn't check the Jaguar S and X type recommended grades. As an aside I also use the Jaguar oil filter which is a much more robust design than the Zetec filter which is standard for the V6 Ford application. Anyway, the oil man told me that under duress of heat and mechanical pressure, synthetic oil will form a solid barrier at the molecular level to protect the surfaces, That made me feel better about the variable pressure.

It would rather help if the handbook for all the various models was a bit more specific about important things such as oil pressure.....otherwise what is the point of fitting the instrument?

Typical of Morgan cutting costs and having a general handbook.

It depends also if the gauge is a mechanical one which tells more precisely the figures or if it is an electronic meter. BTW which oil is best for a MK3 Roadster Sport engine. On the filler is printed 0W20. Is this the best sort?

Interesting response Dave.

Thanks for all the responses. I'll all Morgan and ask them as I'm sure that it has dropped since the last time I had it and even if 1 bar is ok, it could be on its way further down.

It's the mondo st220 lump for those who wondered. It's been re mapped and had a performance exhaust added so is kicking out 245bhp... This may have an effect?

Will update all when I've resolved it. Thanks again.