Club 80-90 Forums

Afternoon all,If i drive down the steep bit of our track/drive [20deg] the oil pressure drops from 3bar to 1bar[oil cold and at tick over] and doesnt rise when the engine revs are increced!.
any ideas?

could it be that the oil has moved away from the pump pick up at that angle so cant pick it up from the sump. what happens on levle ground?

neil

Hi Neil,yes that has to be the explation,and yes the pressure returns to normal on the flat[10deg or less].
My guess is that the oil is being sucked into the pump through the pressure relief valve[when the oil pickup is out of the oil].
It just seems odd that this happens on a van that is supposed to be ok up to 50deg.

been thinking of this myself.

http://www.accusump.com/" onclick="window.open(this.href);return false;



lee.

Thanks Lee,I wonder how it plumbs in?

dave friday wrote:Hi Neil,yes that has to be the explation,and yes the pressure returns to normal on the flat[10deg or less].
My guess is that the oil is being sucked into the pump through the pressure relief valve[when the oil pickup is out of the oil].
It just seems odd that this happens on a van that is supposed to be ok up to 50deg.

Watching this with interest.

Oil pick up pipe out of the oil @ 20 degrees

If this is a fact, it might be a pretty important fact !

20 degrees, I bet there are a fair few normal roads in the UK that exceed that, I can think of 2 very steep inclines near us (in N. Wales)

I bet the syncro off road guys might have some info on this, come on in...

the acusump system if i remember correctly is basicly a spring loaded storage device. you start the engine and the oil pump forces oil in to the vessle which in turn forces the spring system back to the pressure required. then if you get oil surge when the pressure from the main oil pump drops the vessle releases some of its pressure. it only works for a given period of time and then it will run out of oil and pressure.
the idea being that by the time the vessle comes close to running out of pressurised oil the main oil pump has taken controll again.

these were quite successful on wet sump race cars during hard cornering oil surge could run the bearings dry and then bye bye motor.

for off roading the time when surge can occur i imagine could be a lot longer and whether this system would be effective at those time scales i dont know.

lee.