Seriously?

[Laird Scooby]

Originally Posted by foggyjames

I can well imagine that oil pressures in that range could cause leaks - sealing technology has come on a long way! I suspect I have fun ahead getting my B30 to remain oil-tight! In the interests of cordiality I'm going to bow to your greater familiarity with these engines when it comes to the cause, but I do remain a little sceptical!

Out of interest, do the oil pumps have a pressure relief / over-pressure valve?

cheers

James

I understand your scepticism, i was also sceptical when i was first told this ~35 years ago. It is right though.

There is an oil pressure relief valve, yes. From memory it's set to open at 65psi but i may be wrong on that. Also many of the later, larger engine models (3.9 upwards) if they overheated they could cause the oil pressure relief valve spring to go weak, causing it to open much too early like ~6psi which isn't enough to protect the engine - you can guess the end result!

Also many moons ago i ran a series of Mk2 Cavaliers, all 1600 and they shared a problem with the oil pressure relief valve spring going weak. This showed as the oil pressure light flickering at idle even when cold and barely 2bar of pressure hot and running (2000rpm or higher) according to factory fitted gauges.
The spring was ~£3 at the time, took about 5 minutes to fit and cured it instantly.