LOW RPM LOW OIL PRESSURE?

by jan kerstens in General Tech Discussion 11 years ago

Hi,

Installed a thermostat and purged the oil system as required. Checked all connections: OK. Oil level OK. Tappets OK.

2000 rpm 1,0 bar oil pressure, 3500 rpm 3,2 bar oil pressure.

Questions:

1. is this normal?
2. if not is perhaps the VDO sensor faulty?
3. ?????

Cheers Jan

Re: LOW RPM LOW OIL PRESSURE?

by bill martin » 11 years ago

bill martin

10 757 0

Jan,

2 to 5 bar is normal. .8 bar is the minimum allowed. Could be the VDO. Best way to check is to buy a cheap mechanical pressure gauge and temporarily tee it into the oil line between the VDO sender and the engine. If the mechanical gauge reading is the same as the VDO, it could be the oil pressure regulator. If you have the older ball type valve, you might want to change over from the ball to the cone shaped valve. It is a simple fix and one of the few things that don't cost much. You might try just pulling the spring and ball out and give them an eyeball inspection.

If the mechanical gauge reads higher than the VDO, it could be the VDO or the instrument panel gauge.

The oil thermostat wouldn't cause a pressure drop. It just about has to be the VDO sender, VDO gauge, or pressure regulator.

Was the oil pressure OK before the thermostat was installed?

Just a suggestion, but you might want to mount your VDO sender on the firewall or anywhere other than directly on the engine. I've not personally had a problem with the VDO, but I understand that they are prone to failure from vibration.

Bill.

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Re: LOW RPM LOW OIL PRESSURE?

by jan kerstens » 11 years ago

jan kerstens

34 131 5

Hi Bill,

Thanks for the reply. I can not recall that before the installation of the thermostat I had low oil pressures at low rpm.

I have a fairly new Rotax 912 UL engine just 128 hrs so the pressure regulator must be OK. However while testing the engine I did have short term severe engine vibes as a result of dislodged carb diaphragms. The readings were all over the place. Hence it could be the VDO sender.

I will buy a new one: much cheaper and less mess then the solution with the mechanical gauge.

Cheers Jan

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LOW RPM LOW OIL PRESSURE?

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