Cummins QSM11 oil pressure

[Jeremygavin]

I have been monitoring engine numbers since putting the boat in the water this season and the only one that I have questions about is oil pressure. Both engines are reading basically the same so I am assuming I am OK but I would like to get others to comment on what they are seeing in real world numbers on their engines. The engines have about 760hrs on them and I have Amsoil 15w-40 oil in them That was changed last fal and has about 20hrs on it since then.
At 2000rpms I am getting fluctuating readings on Smartcraft gauges anywhere from 27psi to 38psi and they fluctuate between those numbers constantly but stay mosty in the low 30s. My biggest concern is after running at cruise for a while and coming back to idle pressures in both motors is around 17-18psi. Going back to cruise it goes back up to the low 30s again. Are other people seeing pressures similar to these specifically the lower pressures at idle? I pulled the specs for he engines from Cummins and it does seem they are in spec (below says min 10psi at idle and min 30psi at max rpms but I wasn't excepting such a low PSI at idle.

 

[ttmott]

Mine are definitely higher both at cruise and idle (1850 RPM / 650 RPM) at operating temp. Did you compare to the gauges on the engines?

 

[Jeremygavin]

Mine are definitely higher both at cruise and idle (1850 RPM / 650 RPM) at operating temp. Did you compare to the gauges on the engines?

Not yet, I need to get down there next time I am out to check the gauge.

 

[quality time]

Mine run around 40PSI at cruise with no fluctuation. I'll have to check idle speeds this weekend.

 

[spikedaddy99]

I'm in the mid to upper 30s at cruise. 1850-1950 rpms. Didn't look at idle, but I will.

 

[Havana Shamrock]

Same here 30’s with no change and using rotella

 

[Jeremygavin]

I ended up taking 2gal of oil out of each motor to get me to the 7.5gal that Tony Athens advocates and that fixed my fluctuations at Cruise. Now I am a constant 37psi on both motors. This is the same on the mechanical gauges on the motors. However, It still drops to around 18psi when coming off cruise and stays there for a few
Minutes and then pressure builds back up to around 20-21 at 600rpms. Can you guys take a look at what your PSI is at idle after coming off a run so I have an idea of what other people are seeing under those conditions

 

[quality time]

Sorry, I took note a few weeks ago but forgot to post back. 40 PSI at cruise and 21-22 at idle after a run. 38 at cold start.

 

[Jeremygavin]

Sorry, I took note a few weeks ago but forgot to post back. 40 PSI at cruise and 21-22 at idle after a run. 38 at cold start.

Thanks for the numbers. I am
Not too far off that but still it is slightly lower.

 

[spikedaddy99]

Jeremy, I hold a steady 18.5 at idle.

 

[Jeremygavin]

Jeremy, I hold a steady 18.5 at idle.

Thanks, that about where I am at as well. It will stay at around 18psi for about 3-5min and then goes back up to around 20psi at idle after that.

 

[spikedaddy99]

Thanks, that about where I am at as well. It will stay at around 18psi for about 3-5min and then goes back up to around 20psi at idle after that.

Our return home is a 30 minute idle to home port. I never rose back above 18.5.