Low Temperature Pumpability of US Army Diesel Oils

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Wow-12 to 14 MINUTES for rocker arm lubrication on a cold 6.2 (assuming also 6.5)!?! Sounds like a serious case for 0W30, or at least 10W30, in extreme cold. The 10W30 T5 that I ran in my 6.2 last year made a big difference in cold crank speed-but it didn't get to -15F, either.
 
Originally Posted By: bullwinkle
Wow-12 to 14 MINUTES for rocker arm lubrication on a cold 6.2 (assuming also 6.5)!?! Sounds like a serious case for 0W30, or at least 10W30, in extreme cold. The 10W30 T5 that I ran in my 6.2 last year made a big difference in cold crank speed-but it didn't get to -15F, either.


A 6.2 has to crank for 20-30 minutes in the cold to get it to start (if it starts). Does that mean it's already lubricating by the time it finally starts?
 
Originally Posted By: Miller88
Originally Posted By: bullwinkle
Wow-12 to 14 MINUTES for rocker arm lubrication on a cold 6.2 (assuming also 6.5)!?! Sounds like a serious case for 0W30, or at least 10W30, in extreme cold. The 10W30 T5 that I ran in my 6.2 last year made a big difference in cold crank speed-but it didn't get to -15F, either.


A 6.2 has to crank for 20-30 minutes in the cold to get it to start (if it starts). Does that mean it's already lubricating by the time it finally starts?


No, the engines were cranked via an external drive from another engine at the limits of pumpability of the oils (they chilled them to find the limits)...engine had the injectors disabled so it COULDN'T start.

Army was testing the limits of pumpability of their oils in their typical engines.

Can actually gather the most from the paper by reading it.
 
Originally Posted By: Shannow
Originally Posted By: Miller88
Originally Posted By: bullwinkle
Wow-12 to 14 MINUTES for rocker arm lubrication on a cold 6.2 (assuming also 6.5)!?! Sounds like a serious case for 0W30, or at least 10W30, in extreme cold. The 10W30 T5 that I ran in my 6.2 last year made a big difference in cold crank speed-but it didn't get to -15F, either.


A 6.2 has to crank for 20-30 minutes in the cold to get it to start (if it starts). Does that mean it's already lubricating by the time it finally starts?


No, the engines were cranked via an external drive from another engine at the limits of pumpability of the oils (they chilled them to find the limits)...engine had the injectors disabled so it COULDN'T start.

Army was testing the limits of pumpability of their oils in their typical engines.

Can actually gather the most from the paper by reading it.


You missed the joke there :p

The 6.2L diesels are extremely cold blooded and often refuse to start at all once the temperature gets anywhere near or below freezing.
 
Still posting other people's work?

As you have said in the past, as long as the oil will flow into the pump, for each revolution of the engine a positive displacement pump will, in theory pump an equal amount of cold oil as it would hot oil.

In that case, everything else being equal, cold oil should reach all engine parts at the same time interval as hot oil.

But the information in the above link supports the long held knowledge that thin oil reach all engine parts sooner than thick oil.

My guess the reason for that is, at low engine RPM, more oil is leaked from engine components and less oil is being delivered to the engine per revolution while the pump is in relief.

If the oil pump relief was blocked for the cranking test, do you think the thick oil would reach engine parts sooner in the above tests?

I'm thinking the low relief pump setting is part of the problem with the 6.2L engine, or the pump relief passage is too large.
 
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Originally Posted By: used_0il
Still posting other people's work?

As you have said in the past, as long as the oil will flow into the pump, for each revolution of the engine a positive displacement pump will, in theory pump an equal amount of cold oil as it would hot oil.

In that case, everything else being equal, cold oil should reach all engine parts at the same time interval as hot oil.

But the information in the above link supports the long held knowledge that thin oil reach all engine parts sooner than thick oil.

My guess the reason for that is, at low engine RPM, more oil is leaked from engine components and less oil is being delivered to the engine per revolution while the pump is in relief.


Yeah, still posting others work...beats making stuff up.

The papers are purposely at the extreme range of pumpability, whereas my stance is that when in the reasonable operating range there's little/no difference.

Extreme pumpability, the oil is often not even making it to the pump in full volumes.
 
Originally Posted By: Shannow
Originally Posted By: used_0il
Still posting other people's work?

As you have said in the past, as long as the oil will flow into the pump, for each revolution of the engine a positive displacement pump will, in theory pump an equal amount of cold oil as it would hot oil.

In that case, everything else being equal, cold oil should reach all engine parts at the same time interval as hot oil.

But the information in the above link supports the long held knowledge that thin oil reach all engine parts sooner than thick oil.

My guess the reason for that is, at low engine RPM, more oil is leaked from engine components and less oil is being delivered to the engine per revolution while the pump is in relief.


Yeah, still posting others work...beats making stuff up.

The papers are purposely at the extreme range of pumpability, whereas my stance is that when in the reasonable operating range there's little/no difference.

Extreme pumpability, the oil is often not even making it to the pump in full volumes.


Hence the MRV test IMHO. Using an oil outside the CCS/MRV limits is a recipe for disaster.
 
We can throw that comment back to your favorite subject of M1 0W40.
You are selling cars valued up to $300K world-wide from Dubai to Moose Jaw.
CAFE has nothing to do with your decision.
Which one engine oil can you put into these vehicles that will work in every location imaginable?

Well we all know the answer and why, but depending on local weather conditions,
there can be more than one correct answer once the car is delivered.
 
a 0W40 as a "stick that in anywhere" would statistically be the least wrong answer to every question. But as you say, there are a more correct answers if the question is formulated appropriately, with vehicle and climate.
 
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