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Low oil pressure at idle on 6.2

mcarr27656

New member
I purchased 2 brand new, not rebuilt, 6.2 long blocks with oil pan and water pumps. They were put in a 2001 Sea Ray 340 with V drives. I am using the correct 25w 40 mercruiser oil. Correct amount of oil in both engines and new AC oil filters. I have installed 0 to 60 psi mechanical gauges, that read in 1 pound increments, on both engines. I ran both engines at the recommended break in rpm’s and times. I have installed new oil pressure sending units and low oil pressure alarm sending units on both engines. Both engines read identical temperatures and oil pressure temperatures throughout the rpm range, double checked with an infrared temp meter. I am getting the following oil pressure readings.
Cold start - 48 psi port / 38 psi starboard
1 hour at 2200 rpm – 44 psi port / 35 psi starboard
At idle after 1 hour at 2200 rpm – 44 psi port / 9 psi starboard
1 hour at 3,800 rpm – 42 psi port / 30 psi starboard
At idle after 1 hour at 3,800 rpm 25 psi port / 4-5 psi starboard with low oil pressure alarm on.
I am being told by the company I bought the engines from that this is normal and at idle they only need 2 psi. Even though the low oil pressure alarm is on. Need some advice on what is going on with this starboard engine.
 
Could be the pressure relief valve, usually in the oil pump. Since these are remanufactured engines, could be an oil passage plug, removed for cleaning, wasn't reinstalled. 2 psi at idle on a remanufactured engine is not normal. Excessive bearing clearances can also be the cause. Usually rod or main bearings, but could be cam bearings. To check the rod & main bearings, pull the pan, get some Plastigauge. https://www.plastigaugeusa.com/how.html
If these are gas engines, a high volume or racing oil pump could help.
 
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