I have a 1971 4/4 Competition, Kent engine (not sure if still original). Car runs very well and oil pressure is OK but:
On Start up pressure is immediate, no lag and is steady somewhere short of 50 PSI when warm and running.
What concerns me is that gauge show little or no change when idling and when engine is turned off pressure drop is not immediate, sometimes talking several minutes to drop off and then in two stages.
I thought that gauge maybe defect and had it tested when in the UK last September (i live in Austria). Gauge was returned as checked and in order. I temporarily installed a standard Smiths circular gauge but got the same behaviour.
I have had several suggestions from friends and VDO (Instrument supplier in Austria):
1) Bleed off any old oil in line between Block and Gauge - done, no change
2) Increase bore of pipe between block and gauge even though constriction at gauge will be the same as now. Yet to try this one.
3) High oil pressure relief valve not working. (Indicated pressure does not exceed 50psi regardless of rpm!) Not sure about taking this on myself.
Oil pressure as such does not seem to be an issue but since we have some long trips coming up it would be good to have more faith in the gauge reading.
Anybody with similar experience?
Oil was changed maybe 5000km ago and is currently a mineral 20/50 a bit heavier than that used before. Could the heavier oil impact on this?
I've also thought about installing an oil pressure warning light in parallel with the gauge. This I might do if I try the second option above. If I do what rating should the oil pressure switch be, 15psi?
I welcome any comments!
Many thanks
Martin
