Oil pump issues. Pump failure?

[silvreclips]

Little background info. Rebuilt motor back in Spring 08. Has approx 30k on it. Put a topline oil pump on it. After 1.5 yrs it started acting up in a similar way as this one. Idle pressure was really low when warmed up and pressure would fall off randomly when driving but would build back up if you reved it. Replaced it with a milling oil pump and after 1 year its doing the same thing only worse. Idle oil pressure is very low when warm.

This is getting rediculous having to replace the oil pump every year something has to be causing it to have low pressure. I dont think its a gauge problem since the pressure builds up fine when reving the motor its just at idle. I do have a sandwhich adapter on the oil filter with an external oil cooler attached. Never had an issues with that setup on the stock motor before it blew.

Planing on changing it with an oem pump but really would like to try and figure out why 2 oil pump have failed so quickly.

Heres a quick vid of the issue.
http://s189.photobucket.com/albums/z173/SilvrEclipse/VID00001-20100824-1327.mp4

 

[VelocitàPaola]

Where is the oil pressure gauge connected to the system? If you rebuilt the engine, did you also replace the bearings and check the clearances between the crank, block and rods?

 

[silvreclips]

The oil pressure gauge is Ted with the oil feed off the back of the block. The oil pressure gauge is the middle gauge on the pillar. Its an autometer cobalt full sweep electric. I wouldn't think that the gauge is the problem since it works and doesn't jump around just goes low at idle. Going to try a mech. gauge also just to rule the gauge out.

When the motor was rebuilt the crank was turned .01 and the bearings were all plastigaged and within spec. Could that sandwhich adapter be causing a restriction in the oil system maybe? Im going to remove it and test the car again.

 

[smrogers5771]

Bearings man... was the crank balanced? the rod bearing will cause the fluctuation in pressure.... time to change them. Trust me I have had this happen. on my old 420a at idle cold 60+PSI after it was warm maybe 12PSI.... any lower and a bearing would have been thrown and well BOOM! change em. and check the crank to make sure it is within spec

 

[silvreclips]

Changed the oil pump and it didn't seem to help at all. Oil pressure gauge sits dead on 0psi at idle when its warm. Pressure goes up to around 40psi when the motor is about 2k rpms. Let the car idle for about 10minutes with the gauge sitting on 0 and the car never made a bit of noise, lifters were quiet and no knocking. Checking the gauge tmrw with a mechanical gauge to see if the gauge is accurate or not.

Regardless of the results Im driving the car untill the motor tears up. Tired of working on this pos

 

[silvreclips]

did some testing today and it turns out the gauge is reading 10psi off so the motor is getting enough oil. going to try and change the sensor and see if that corrects the issue