[Healeys] [Fwd: Oil Pressure Control]

[Chris Dimmock]

Ok. I'll post my oil pressure figures. With a bled valve.
The black and white car is due for an oil nad filter change anyway.
Weather permitting.
Me

Sent from my iPhone

On 01/10/2010, at 4:04 PM, Joe and Lenore Armour <sebring at illawarra.hotkey.net.au 
 > wrote:

> FWIW  I have never been able to accept that the crude Healey (all  
> BMC for that matter) 'pressure relief' valve, opens and closes that  
> many times per second to manage the oil pressure we see at the  
> gauge. The seat and valve are too poor a fit to be a positive seal  
> and it  does not remain shut until a certain pressure is reached.   
> The volume of oil that flows thro a restriction, ie bearings and  
> spray holes etc varies with tempreture, engine speed and general  
> condition and bearing clearences.
>
> May I suggest that our 'relief valves' are flow control valves and  
> apart from when the engine is stopped, the valve is never in the  
> closed position and thus providing a positive shut-off. The spring/ 
> valve manages pressure by controlling the volume of oil allowed to  
> by-pass into the sump.If you inspect a valve it usually is a loose  
> fit in the bore and shows signs of having wear on opposite sides at  
> the two ends, an indication that it spends most of its life rocking  
> back and foward in its bore. Usually most of the oil supplied from  
> the pump should be far in excess of the volume that can circulate  
> thro the engine and therefore is continuously being by-passed back  
> into the sump (pan).
>
> Most hydraulic system start-ups require ALL air to be bled before  
> commissioning.
>
> Therefore it is most likely the weak spring tension that is allowing  
> too much oil to by-pass when pressures are insufficient with the  
> engine in GOOD condition