420A Low oil pressure

[Eclipse420aTuner]

Troubleshooting an 420a engine rebuild I've finished recently-
Oil light is on and I'm hearing some tapping in the head. I've got plenty of oil and used an pressure tester to find it will initially idle at 12psi and slowly drop to 5 over a couple of minutes.

My plan of action is check in the head for any loose bolts and take off the oil pan to do the same-ensure I don't have a physical leak. I didn't replace the oil pump at the time of rebuild, as it is actually pretty new still. But I may still go ahead and replace anyway, but any other pointers on what else I should investigate?
Any help is greatly appreciated.

 

[1990TSIAWDTALON]

What were your bearing clearances (main and rod) when you assembled it? It sounds like excessive clearances, but I will hope that it isn't. Crossing fingers.....

 

[BLACK'98DSM]

Make sure your baffle mesh isn't clogged up. Mine had a little trash in it that I had to clean out before reassembly. Also check that little o-ring on the end of the baffle tube. Mine was cracked as well.

I honestly wouldn't doubt the oil pump is going out though. Some of those aftermarket ones aren't the best quality. Your pressure should never get below 20 psi. I've seen mine as high as 150 psi in the winter.

 

[dustyboner]

the service manual says standard value for oil pressure at curb idle (engine fully warmed up) is 4 psi. That doesn't seem right though. I don't think i have ever seen oil pressure below 13 psi on a healthy 420a.

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specs for oil pump

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bearing clearances

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[BLACK'98DSM]

the service manual says standard value for oil pressure at curb idle (engine fully warmed up) is 4 psi. That doesn't seem right though. I don't think i have ever seen oil pressure below 13 psi on a healthy 420a.

I find this to be very interesting. If my gauge ever shows 4 psi, I'll be immediately killing the engine.

On my other engine, I was still running the stock 22 year old oil pump, and it idled at ~28 psi if it was HOT. With my new engine and oil pump it idles around 40 psi when HOT. And that's with 10w-30.

I think this might depend on where your gauge is attached to. But I've always had mine hooked up where the stock OPSU was.