Oil light and buzzer

[pitaman]

My new motor built 1500km ago cti bottom end 2l crank mp9 head running good quality 20w50 oil new gmb oil pump 2.6 kombi pistons

About 400km after rebuild the oil light and buzzer came on for a short while then off so I serviced the car and again after driving about 600km on one day the same thing happend on for a minute or 2 off again

Took the car out again today for a 40km trip one way no problems but when n returned hom again oil light and buzzer light on and buzzer at high and low revs and after car idles for a while both go dead no funny noizes in motor oil temp between 90 to 100 degrees and no my oil pres gauge is not working

Is there a mod to increase oil pressure on 2l conversion must it be done?
Any advice will help at this stage

[PapaJo]

Fix the oil pressure gauge for starters and then you can verify the oil pressure.

If pressure is still fluctuating, next step is to remove the sump and check out the gmb oil pump. You don't say if this is the CTi 8V pump or the 2L oil pump from a 2e motor. The 2e pump has longer body and gears to give you more volume at the same pressure. Check also the 2 bolt flange on oil pump pick up if it has not started to loosen the 2 bolts by itself. There is also an o-ring behind this little flange over the tube.

Did you replace the oil pressure switch during the rebuild?

[pitaman]

Ok fixed oil pres gauge startup idle 5 bar then comes down to 3 bar idle and as soon as car heats up oil pres drops to 2.5 and lower even at revs so ja going to drop the sump