Car idling oil pressure issues...

[ken_junyi]

To all the sifu and gurus out there. I hope u guys can assist on my probs... My ride is a dc5 n I'm running on a k20a block which was recently rebuilt with high comp wiseco pistons and Brian crower rods. I've replaced all my thrust bearings, piston rings etc for new ones. Even my oil pump is new. Did a full tune about a week back. So here's the problem. This block was bought over from a fren. When the block was in his ride, his idle oil pressure is at around 3.0 x100 kpa. But after I took over the block with it being entirely overhauled, my warm idle oil press is at 2.6 x100 kpa.

So here's the thing. When my engine is on full load, my oil press is at 7.0x100 kpa. But after a couple rounds of hard driving. My idle oil pressure drops to a ridiculous low reading of 1.9x100 kpa instead of maintaining at 2.6x100 kpa. If I stop hard driving the car, it will slowly climb back up to 2.6x100 KPa.

I tried switching out my oil from 10w40 (FK massimo racing) to 15w50 (motul 300V). Even changing my defi oil pressure sensor to new ones. But I'm Still having the same issue. I'm trying not to remove the entire block to check the internals due to the high cost of labour. I seriously hope it's not an engine issue as I Juz built this motor about a month back.

So can any gurus/experts give any advise on what maybe causing this issue?? Your feedbacks are greatly appreciated!!!

 

[Izso]

Thicker oil and the pressure remains the same? What's the oil temp after a hard run and on normal idle? What oil filter are you using? What oil pump you using? What thermostat are you using? Temperature sensor for the fan working ok?

I don't see a problem with lower pressure. Slower moving oil during idle after a hot run would make sense since the oil would be more viscous and easier to flow.

 

[ken_junyi]

Yes bro... Thicker oil... Oil press still the same at 2.6 and drops to 1.9 after hard run. But oil temp peaks at 90. Never even hit hundred. Oil pump using stock type r oil pump (new), not sure abt the oil filter, thermostat sensor and the fan sensor though. How would these affect the oil pressure in any case??

 

[Izso]

I'm just thinking how thick the oil would be at different temperatures. Engine oils are rated at 100 degrees celcius so you using 15W50 means it's 50 viscosity at 100 degrees. If 90 degrees I think it's more or less the same. If the cooling is good (low temp thermostat and strong fan) then it's likely the oil temp would be cooler therefore slightly thicker viscosity which would probably increase pressure to some extent.

Honestly though, if the car feels fine and runs fine and you're sure the oil pump is good (and not a lemon unit) you should ok to go. 1.9 isn't that low. I sometimes get that on my humble wira after a hard run and you're driving a much more aggressive VTEC engine!

 

[ken_junyi]

Haha thanks a lot bro for ur advise. Just removed oil sump to check my baffle plate, oil pump, con rod bearings. All in good condition. So I guess everything shld be fine.... Thanks for the advise!!! Really appreciate it!!!