Oil pressure, temp and viscosity

[digger]

Remember, you're measuring at the BOTTOM of the pan, where, in theory, the oil's
cooled the most by the pan.

Yes, there's an oil pressure relief valve- cold, mine holds close to 70,
and hot, 60 is normal

Yes, there's a thermostat in the oil head bolted to the side of the block, where the lines split off to the cooler.

My numbers, from a 160k engine, are that oil temps run 190- 200, pressure is limited
at 60, and idle just lets the 20psi light come on sometimes after I've been chasing a train
in hot temps for a lot of laps, when the temp can get up to 240.

hth

t

Yes the pan is not ideal are your numbers taken in the pan? Maybe someone has measured the pan and somewhere a little better and can give some correlations....

[digger]

If the temperature is around 20C, I would prefer 15W40 oil. An IR temp gun is a cheap and accurate way to measure the oil temp.

How does the viscosity for 15w-40 at say 40f compare to 10w-50 in general? without seeing graphs vs temp i'd guess it be thicker for cold start but maybe only at extremely low temps

[TobyB]

Remember, you're measuring at the BOTTOM of the pan, where, in theory, the oil's
cooled the most by the pan.

Yes, there's an oil pressure relief valve- cold, mine holds close to 70,
and hot, 60 is normal

Yes, there's a thermostat in the oil head bolted to the side of the block, where the lines split off to the cooler.

My numbers, from a 160k engine, Mobil1 15-50
<edit- measured in the bottom of the pan as well>
are that oil temps run 190- 200, pressure is limited
at 60, and idle just lets the 20psi light come on sometimes after I've been chasing a train
in hot temps for a lot of laps, when the oil temp can get up to 240.

hth

t

[dnguyen1963]

If the temperature is around 20C, I would prefer 15W40 oil. An IR temp gun is a cheap and accurate way to measure the oil temp.

[digger]

SPECS:

so i have an oil pressure sensor (same location as OEM warning sensor) and an oil temp sensor that is the oil pan drain plug (not ideal). i use a 10W-50 oil and have the stock m20b25 oil cooler and my idle speed is 925rpm. the pressure sensor retains the warning light but at 13psi instead of 7psi as per stock switch (or is it 9psi??)

COLD FIRST THING IN MORNING

in the cold/cool morning at idle and at speed the pressure remains at 70psi

SPRING AFTER WARMUP

on a 20-25C/68-77F sort of day when the engine is fully upto temp at idle the oil temp is apparently around 75C-80 when just been cruising around. the oil pressure would be between 25-30psi thought its hard read accurately

GIVE IT SOME STICK

if i give it some right foot for a period of time the oil temp goes upto 200F (93C) and pressure will drop to between 15-20psi but temps will come back down after just cruising around.

THOUGHTS

based on this id say the oil is too thick as when cold the pressure is way up there even at idle and surely this means the flow is reduced during warmup.
The oil is not getting hot enough under normal conditions and a thinner oil might be more suitable.

i'm looking to try a 10W-40 to see what effect this has, it should be thinner when cold despite still being a 10W and it might suit the temps mine currently sees a bit better.

QUESTIONS

I assume when cold there is a relief valve that regulates this maxima or circa 70psi? is this in the pump or the one that screws into the block inside the pan?

i'm interested in the oil temperature, is there any sort of thermostat that is supposed to be operating? id like to see a bit higher temperature under normal conditions to burn off condensate and reduce dilution.

Does anyone have similar data?