Oil pressure gauge??

[andys2]

I’ve just fitted an oil pressure gauge to my RV8 and I need some advice about it. First of all I’m not convinced it’s reading correctly as I cannot bleed all the air out of the line ( it’s a capillary type ) every time I switch off the engine the oil drains back and the line fills with air bubbles. When I restart the engine the bubbles clear but the oil never gets all the way to the gauge, so there is always air acting on the gauge. Surely it cannot be reading accurately if this is the case?
At first I was getting 12psi at idle ( hot ) and peaking at 24psi when driving, this was on 15W40 Castrol GTX. I’ve since switched to 20W50 Castrol and it’s now reading 20psi at idle and peaking at 30psi. Still seems a little low to me but I need to know that it’s working correctly before I start re-building the oil pump.
Any advice appreciated.

Andy

[Pigeon]

Air bubbles are not a problem. The air will compress until the pressure is equalised throughout the capillary and the gauge will read correctly.

[MGBV8]

Andy,

The V8 is high volume low pressure and older versions, P6B and SD1's had running pressures of around 20psi at 3000rpm hot and nothing at idle.
The oil pressure relief valve for MGBGTV8 was 42psi. The engine is not designed to cope with high oil pressures much above this.

The idle pressure is usually 10-20psi with around 40max

Paul