Oil weight

[KARNUT]

Let me clarify Karnut.
Oil changes at 200 gallons of fuel were not for equipment.
This was his choice from oil samples he seen for his vehicles.
Was he going overboard?
Probably.
 
[emoji4]
 

So every other fuel up for OTR trucks? Some of those go many thousands of miles between oil changes. Usually they go by HRs too, lots of idle times. He was either joking, pulling your leg or he meant HRs.


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[diyer2]

ONE more time.

Not for equipment.

For his personal vehicles.

 

[sdeeter19555]

Let's assume an average speed of 35mph (which is actually high) over said 3000 miles...that would be about 85 hours of run time. Most small engines with an pressurized oil system recommend 200 hour OCI. So assuming 100 hrs per 3000 miles, you could extrapolate a 6000 mile OCI assuming things are fairly consistent...and the majority of the OLMs get 6500 miles or so?

Just another point of view...

As with Karnut, I remember some of the OCI being between 500 and 1500 hours on the HD equipment I've used in the past...obviously those pieces of equipment have huge sumps as compared to our 6 to 8 quart systems.


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[Black02Silverado]

2 hours ago, sdeeter19555 said:

My only comment is that, while a used OIL analysis can provide some indirect insight into engine condition, a used OIL analysis only tells you how well or not well the oil held up.

Too many times people claim engine condition using UOA, and that is not correct.

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In what way do you mean they claimed engine condition and it wasn't correct but had a UOA to show otherwise?  Just curious.  If a UOA isn't worth showing the condition of the engine then why does the aviation use it as a means to prevent problems?  Not like you can just pull over on the next cloud and wait for a tow plane.

[Pearl2017]

I'm hearing a bunch of tidbits of beliefs about thinner vs thicker and why thinner is spec'd and is it adequate. I'll throw my bits into the bytes and hope to tie it all together.

 

First the WHY. We all know that manufacturers are forced to continuously increase mileage and one solution is to use lower Viscosity. But To use lower viscosity REQUIRES tighter tolerances to maintain oil pressure. Someone has suggested this and someone else scoffed at that, sorry you are wrong. Of course this balancing act of viscosity vs tolerance works fine on a NEW engine. HOWEVER If just one bearing starts to go out of tolerance, oil pressure in that bearing will drop much more quickly and with less safety margin than with higher viscosity which wont leakdown and drop pressure as easily. When someone says they want more of a safety margin this means higher viscosity oil which really just means less chance an oil pressure drop will be a problem at any bearing in the motor. As long as you pay attention to flow at lower temperatures increasing viscosity adding to safety margin wont cause any problems.

 

The reason a Corvette is spec'd to use 15-50 is precisely because of the importance of maintaining fluid bearing pressures against the extreme loads they see. And the high temperatures trying to drive down the viscosity at the same time. ...And that 15w-50 can have a massive dose of anti wear additive that "Energy Conserving" oils cant.

 

Years ago I did board level repairs of gauging electronics from the crank, rod, and piston machining lines in the Chrysler plants in Detroit area. Let me say the bearing tolerances that escaped the statistical QC program were astonishing. And the engine failures of the time reflected it. The fact we don't see that these days says a lot But I still prefer to increase my safety margin and to heck with the CAFE recommendations.

[sdeeter19555]

In what way do you mean they claimed engine condition and it wasn't correct but had a UOA to show otherwise?  Just curious.  If a UOA isn't worth showing the condition of the engine then why does the aviation use it as a means to prevent problems?  Not like you can just pull over on the next cloud and wait for a tow plane.

You can have a completely worn out engine produce wonderful UOAs...

I've seen it first hand, engine rings were so bad the thing would barely run because compression was so low, had almost no oil pressure because the bearings were worn out, UOA indicated the oil was fine and the engine was in good condition...

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[Grumpy Bear]

Misuse of the terms tolerances and clearances is killing me. I’m pretty sure most are using tolerance when they really mean clearance. The clearance is .002” the tolerance is +/-.0005” meaning .0015 to .0025” is acceptable. That said I do believe it is the tolerances and not clearances that are in fact tighter.

Motors built with hypereutectic pistons for example may have wall clearances of under .001” which would seize a motor with a forged piston and yet provide the same viscous drag at running temperatures. There are allot of hypereutectic pistons in use these days. Dimensional stability is ring stability and with low tension rings it’s pretty important.  

Dynamic oil film thickness, rods and mains, could care less about the bearings radial clearance (within reason) IF there is enough pump volume and a tight enough side clearance. Yes it cares greatly about the rod bearings side (axial) clearance which is what controls the bearings flow rate and indirectly it’s temperature thus dynamic viscosity.  

The side clearance is the finger over the end of the hose. The hose can be full no mater it’s diameter even at low volumes if you finger is restricting enough flow.

Once a free running clearance more clearance doesn’t reduce drag. If fact it can increase it. So it’s the oil viscosity, which by definition is shear drag that is reduced with a lighter, less vicious oil. It’s got little to do with clearances but more and more with hardness.

Your designer selects his oil viscosity based on EXPECTED temperatures and LOADS. Actual in the sump temperatures and actual average brake mean effective cylinder pressures and gives it a ‘safety margin’. Less generous as times go by and the idiot law makers continue to ask for the more and more impossible.

BTW Steve is correct. Your motor can be dead to the world and have great oil test scores. But that's for another time. 

[Black02Silverado]

1 hour ago, sdeeter19555 said:

You can have a completely worn out engine produce wonderful UOAs...

I've seen it first hand, engine rings were so bad the thing would barely run because compression was so low, had almost no oil pressure because the bearings were worn out, UOA indicated the oil was fine and the engine was in good condition...

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I understand this, but we are talking new engines that are running fine and wanting to use a different grade oil.

[sdeeter19555]

I understand this, but we are talking new engines that are running fine and wanting to use a different grade oil.

It doesn't matter, a UOA is a used OIL analysis first and foremost...using the data to judge engine condition is only a educated guess.

Where is that copper coming from, why is the aluminum high, is that silicon from a bad air filter or the sealant they sealed the timing cover with?

It only conclusively tells you the condition of the oil.

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[ksfarmdude]

depends what climate you drive in ? I use 10w 30 year round since I am in hotter temps more then cold and also my trucks sit in  a heated garage on chillier nights 

[Grumpy Bear]

I get four things from a UAO. The oils physicals. Vis, Flash, fuel, water,TBN/TAN etc. The oil add pack condition, remaining additive levels so yes, a used oil analysis. Then I get wear metals. Without a point of reference they mean little but against 'universal averages' and the vehicles own history they say a great deal more. Especially if standardized in ppm/1K miles or something similar. They can not tell me how worn the motor is but they certainly can tell me at what rate wear is progressing. 

 

Lastly, if you care to pay for it the ISO 4406:99 cleanliness numbers. Particulate analysis in amount and by micron size. Comparing this to the wear metals can be eye opening me thinks. 

[Nitrousbird]

0W20 is speced to meed CAFE numbers.  It has zero to do with longevity on these motors.  

 

Why do you think GM allows 0W40 and 5W30 in the LT1 for normal duty service (which is basically identical to the L86)?  Because those are in low volume cars (Camaro SS/Base Vette) running that motor.  Don't kid yourself into thinking 0W20 is for best engine protection.

[Grumpy Bear]

3 hours ago, Nitrousbird said:

0W20 is speced to meed CAFE numbers.  It has zero to do with longevity on these motors.  

 

Why do you think GM allows 0W40 and 5W30 in the LT1 for normal duty service (which is basically identical to the L86)?  Because those are in low volume cars (Camaro SS/Base Vette) running that motor.  Don't kid yourself into thinking 0W20 is for best engine protection.

1.) Ring tension. 

2.) Expected use which regulates actual viscosity via targeted temperature. This isn't actually new to anyone. Owner's manuals for as far back as I can remember give alternative viscosity choices for different ambient temperature zones. 

 

Viscosity is chosen with these two items in mind to produce a predetermined but like thickness of oil film on the cylinder walls. @ 10 um. Exact same motor targeted for different applications can also be spec'd for various ring tensions and have different end used, thus load, thus 'normal' temperatures in mind. 

 

20W at 200 F has about the same operational viscosity as 40W at 250 F. @ 10 cSt. People forget that viscosity is a function of temperature as much as it is a function of chemistry. We also seem to forget with ease that 0W30 - 5W30 and 10W30 all have the same 212 F viscosity. The same or nearly the same HSHT viscosity at 302 F (150C) But a HUGE difference at -30 F, -50 F. 

 

GM's choice of 0W20 came WITH the lower and thinner ring packages and the lower wall temperatures, thank you cylinder wall jets spray cooling. The HP versions of these motors also sport more cooing and lower T-stat setting. Lots of puzzle parts to consider. 

 

Just putting that out there. Yes CAFE is important to GM but so is getting the motor to the finish line. 

 

 

[Nitrousbird]

10 hours ago, Grumpy Bear said:

GM's choice of 0W20 came WITH the lower and thinner ring packages and the lower wall temperatures, thank you cylinder wall jets spray cooling. The HP versions of these motors also sport more cooing and lower T-stat setting. Lots of puzzle parts to consider. 

 

Just putting that out there. Yes CAFE is important to GM but so is getting the motor to the finish line. 

 

 

Except from what I can tell, the  LT1 runs the same thermostat as the L86.  Normal driving, the L86 has to work hard, since it is pushing a less aerodynamic vehicle around that happens to weight 2,000lbs more.  

 

So then you have harsh use conditions.  Yes, track days are hard and GM recommends running a different oil on a track day, so that shouldn't be factored in.  Now it is spirited driving.  So what's harder on the motor - romping on it here and there or towing 9,000lbs in a truck that weight 1 ton more?  Exactly.  

 

Cooling?  Cooling systems on these trucks sure look bigger - and get more direct airflow, than the 6th Gen Camaro SS or the C7.  Remember, the finish line was designed to be 5 years/100k.

[mookdoc6]

15 hours ago, Grumpy Bear said:

1.) Ring tension. 

2.) Expected use which regulates actual viscosity via targeted temperature. This isn't actually new to anyone. Owner's manuals for as far back as I can remember give alternative viscosity choices for different ambient temperature zones. 

 

Viscosity is chosen with these two items in mind to produce a predetermined but like thickness of oil film on the cylinder walls. @ 10 um. Exact same motor targeted for different applications can also be spec'd for various ring tensions and have different end used, thus load, thus 'normal' temperatures in mind. 

 

20W at 200 F has about the same operational viscosity as 40W at 250 F. @ 10 cSt. People forget that viscosity is a function of temperature as much as it is a function of chemistry. We also seem to forget with ease that 0W30 - 5W30 and 10W30 all have the same 212 F viscosity. The same or nearly the same HSHT viscosity at 302 F (150C) But a HUGE difference at -30 F, -50 F. 

 

GM's choice of 0W20 came WITH the lower and thinner ring packages and the lower wall temperatures, thank you cylinder wall jets spray cooling. The HP versions of these motors also sport more cooing and lower T-stat setting. Lots of puzzle parts to consider. 

 

Just putting that out there. Yes CAFE is important to GM but so is getting the motor to the finish line. 

 

 

Grumps, 

 

The Piston Spray Cooling nozzles are designed for direct cooling of bottom of Piston or underside of "Crown" they redesigned the underside of Piston to maximize this cooling of significant temperature differentiation than associated engines without this feature....i.e. "Coyote"  Remember the Squirters only come on when called for under specific demand load and temperatures.  I am here for ya bud...you been looking at those pretty F-150's slightly used 2.7EB might be what your looking for?

Edited April 13, 2019 by mookdoc6