Low Oil pressure

[1990 Red Excel]

I'm sure this has been asked before but I am still not clear as to the solution, for a low oil pressure.

Can someone tell me how to get a higher Oil Pressure in my 1990 SE with a 912 engine.

When I switch the Ignition on with a cold engine the 7 Bar VDO Gauge reads 0.

On starting the cold engine the Gauge reads 3.5 Bar.

When warmed up to about 80 degrees and car on the move, and drive about 15 miles the Gauge reads  a constant 2.5 Bar.

Now when I am stationary and with the engine running at 1000 rpm idle speed, the pressure drops into the Red sector on the gauge which is less than 1 Bar.                                                      That to me is very dangerous.

I have fitted a Black 17W37 Oil Filter supplied by SJ Sports and used Castrol  Edge 10W60 Synthetic Oil.

Is there anyway of increasing the oil pressure to a higher pressure when warm and on a run, also more importantly when stationary at idle.

Your help would be most appreciated.

Ian.

[jep]

Use Valvoline 20/50 VR1 oil. The engine was designed for 20/50 Valvoline. Even racing Lotus from that era use VR1, it is a top quality oil. LotusBits, who race these engines a lot use 20/50 VR1.

I would check the gauge is not faulty, check direct from the engine.

My gauge runs to 5 PSI. Always 5+ on start up. When warm, at idle about 1.5bar. At 6000RPM, always over 3 bar warm.

I had a Porsche 928 once with a worn engine. Low oil pressure when warm at idle. I changed the oil to 20/50 VR1 and pressure rose 1 bar.

Change the oil annually or 5000 to 6000 miles (whichever is sooner). 

Justin

 

[andydclements]

@jep10w60 would give a higher oil pressure when warm than 20w50, so I don't see the oil as the problem. When warm the 20w50 behaves like a straight 50w, whereas the 10w60 behaves like a straight 60, so the 10w60 is thicker when warm than a 20w50.

 

@1990 Red Excel  It's not perfect, but not really very bad. These engines are known to have a relatively low pressure when at /near idle. It's to such an extent that some of them had relays fitted which meant that at low idle the oil pressure warning light was extinguished despite the pressure stat's output. When at idle, you have a lot less force on the bits such as big ends, so the low pressure is less inclined to cause real damage.

[jep]

I would still give the VR1 20/50 a go, as it was the oil the engine was designed around. Though independently checking the pressure is a wise move also. 

Nothing causes more disagreement (involving cars) than oil. VR1 has a very good reputation and is used in many Jaguar XK engines (1948-1992) and by many classic car specialists. I don't see it can do any harm and may have the affects it had on my 928.

It is easily available on FleaBay for 5 litres at less than £30 landed. 

Justin 

[Clive59]

Here is an interesting read: https://www.lotustalk.com/threads/what-is-the-best-motor-oil-to-use-in-esprit.377065/

And here:

I now use Castrol Edge Supercar Engine 10W-60 as the current equivalent(and quoted in Jaques post as such from Castrol), available easily, and reasonably, if you search a bit, and I noticed better warm idle pressure compared to the Classic mineral 20W50 used before.

[Jacques]

Good too hear. I've never used that classic oil myself, but some friends have, and they are okay with it in their 40 year old Laverda ball bearing engines. But that is another matter. I would expect the same as you have found, by shifting from Classic to Supercar. Two very different types of oil.

But I will add to the old thread's content, that Supercar is designated so, because Castrol wanted to celebrate their approval by Köenigsegg in Sweden. That is the only difference. I called Castrol UK Headquaters recently and asked the tech department.

And speaking of sludge, created by too much zink for example, I can add that while carmakers advertise their cars to use long life versions, these create way too much sludge, and I have personally seen many expensive heavily tuned Audi RS and VW Golf R engines (for example by HGP, which I have helped work on wither service or engine rebuilds)) full of sludge from long life oil. Just never use it. I avoid it like the covid-19. Keep a long distance  

Kind regards,

Jacques

[Painterdave]

I would go with vaveline 2050  Lotus bits use it 👍

[dave excell]

I had low oil pressure at idle on my Excel but was OK when running at speed. I replaced the oil pump and the oil pressure when hot and at idle went up significantly. Oil pumps dont last for ever. My engine had done in excess of 140,000 miles. South West Lotus Centre do replacement Oil Pump Rotor and Annulus Kits. it may be worth a try.

[andydclements]

The trouble with 20w50, is that it's fine here in the UK climate, but the OP is is a much warmer climate so 20w50 there will behave more like 10w40 would in the UK (and we know that's a bit too thin).

[Elite 4.9]

I always add Lucas oil stabilizer to my oil which is a thick, VERY sticky additive made for all engines. It not only will increase your oil pressure but will also eliminates dry starts when cold and sticks to all bearing and rotating engine parts to make them last longer. It will also give you better cylinder ring sealing which will raise your compression slightly and give you more power and mileage.

I have used it for many years in all my engines and the big truckers swear buy it, buying it by the gallon. A friend with a Detroit diesel ran his 14.8 liter straight six to a million miles before overhauling it !                      He also got up to 8.7 mpg (US) Pretty good for such a large loaded truck powered semi engine.

 It also allows motor oils a higher degree of lubricity which reduces oil consumption.

Great stuff !! 

It has been around for a long time and has been tops in my book for many years and I never drive without it.

https://lucasoil.com/products/engine-oil-additives/heavy-duty-oil-stabilizer

 

cheers,

Richard