AC DELCO OIL FILTER

[donjetman]

It's not just because the oil is thickest, but also because most of the oil has drained down away from the parts because the engine is off and pump not running, no pressure in the system. It takes a second or two to get the oil pressure to build and pumped around the important pieces.

Re-read the second to the last paragraph.

Oil pressure doesn't = film strength. Volume is more important. Cold and/or thick oil= less volume. Warm and/ot thin oil = more volume.

If pressure was the culprit all engines would have electric pumps and/or accumulators on them.

 

[gooffeyguy]

I confess, I didn't read that book you wrote above, lol

Just curious though, What kind of oil volume does an engine at rest have?

Oil doesn't get to places magically

 

[Geotrash]

Thanks for the detailed analysis, Don. Great stuff to consider and learn from.

Dave/Geotrash, your 5w-40 is thicker than the 5w-30 at ALL temperatures, even startup. The people that give oil these #s just for reference, they're otherwise almost meaningless. The low# has almost no meaning. See the charts below and you'll see what I mean. The high # has some meaning.

This part I knew.

So, is it safe to assume thinner oil on startup is better for the engine? I know from my research that a thinner oil will flow more volume (honey vs water), with less resistance and stress on the engine, than thicker oil.

A straight 30wt oil is thicker at any and all temps less than 212F than its multi-wt cousin (see chart below). Imagine these #s at zero degrees or colder.

cSt viscosity at... 75 F...,,,,,,,,,,,,,,,, at 212 F
Straight 30........ 250......................10
10W-30..............100......................10
0W-30................40 ......................10

In the chart below you can see that a 0w-20 oil is thinner at "ALL" temperatures than a 0w-30. And the same can be said between 0w-30 and 0w-40. Dave/Geotrash, the same is true for 5w-30 and 5w-40.

cSt viscosity at. 104F................212F.............at 302F

Straight 30............??.....................10.....................3
0W-20................47 .................8.8................2.5
10W-30..................62 ...................10.....................3
0W-30..................57 ....................10.....................3
5W-30..................59.....................10.....................3
10W-30.................62......................10....................3
0W-40..................85.....................15...................3.75
5W-50...............120...................20..................4

Yes, this I knew also.

NOTICE where they differ greatly is at a less than normal temp? If it's colder than shown in this chart the viscosity #s get extreme.

cSt viscosity range at 212 F
20w - 5.6 to 9.2
30w - 9.3 - 12.4
40w - 12.5 - 16.2
50w -16.3 - 21.8
60w -21.9 - 26.1

Yes, this I knew also.

min. viscosity at 302 F...
20, 2.6
30, 2.9
40, 2.9 to 3.7
50, 3.7
60, 3.7

This I did not know. Very cool.

Synthetic oils do cling to parts better because they have higher film strength than mineral oils. Synthetics are thinner overall. They have greater slipperiness. Yet they stick better to engine parts.

My Yuk 6.2L L92 see's both the TX 100+F heat and the cold -20F Colorado mtn winter. I'm currently running 0w-20 and will see what analysis indicates. It's too early to tell yet, but I'm getting 20-25 more miles out of a tank of gas than I use too. But, I changed all the O2 sensors not long after I switched from 5w-30 to 0w20. Maybe thats the improvement?

After reviewing your post, I did a little desk research on main and rod bearing clearances in the LS engine along with optimal oil viscosities. Turns out that the bearing clearances do indeed favor a lighter weight oil, which makes the case for following GM's guidance.

That said, the primary failure modes on these engines have never involved the bottom end, but rather other internally lubricated parts such as the lifters. Which still makes me wonder if there is anything that's been learned in the engineering literature about the effects of oil viscosity at normal operating temperature (e.g. 212ºF) on the wear rates on those parts.

But I absolutely see your points on the 0w oils and can't disagree with your logic.

 

[donjetman]

The wives tales about oil are many and passed down from generation to generation. Grandads and dads oil isn't what we're using today. Oil has improved greatly. Maybe it's time for some new wives tales

I've seen virgin oil analysis on new old stock of a can of 1970 30w Quaker State. Analysis showed the TBN# to be ZERO . No wonder our engines didn't last very long, and we even changed our oil every 3000 miles.

A new engine apon initial build is assembled with lube on surfaces that need it. Within seconds after first startup sump oil replaces the assembly lube. For the remainder of an engines life there is a permanent film of oil on everything. oil clings. It's a wonderful property of oil, especially todays oil.

Some engines don't have a oil pump. They rely 100% on "splash" for lubrication.

Dave/Geotrash: Toyotas burning oil???? Just so you know, not mine. I have a 2007 Toyota FJ Cruiser all w/aluminum gasoline 4.0L w/VVT. I bought it used w/20k miles in Jan of 2009. It now has 220k miles. It's been my daily driver since Jan 2009. Toyota recommends premium unleaded and changing the oil every 7500 miles. It has never had any fuel other than regular unleaded, and the oil and filter have never been changed at less than 10,000 miles. I've done 13 UOA on the various brands and wts of oil I've used in it. Thru UOA I've discovered it's easy on oil. I've taken its oil change interval out to as far as 18,000+ miles. It doesn't burn or leak any oil. It's never been in a shop for any reason. To date it has never thrown a code. Are there FJs out there that burn and/or leak oil? Certainly. Some folks can destroy a metal ball with a rubber hammer.

I've been discovering for the past 3.5 yrs and 5 UOA that the 6.2L L92 is completely different animal. It's very difficult on oil.

 

[swathdiver]

The wives tales about oil are many and passed down from generation to generation. Grandads and dads oil isn't what we're using today. Oil has improved greatly. Maybe it's time for some new wives tales

I've seen virgin oil analysis on new old stock of a can of 1970 30w Quaker State. Analysis showed the TBN# to be ZERO . No wonder our engines didn't last very long, and we even changed our oil every 3000 miles.

A new engine apon initial build is assembled with lube on surfaces that need it. Within seconds after first startup sump oil replaces the assembly lube. For the remainder of an engines life there is a permanent film of oil on everything. oil clings. It's a wonderful property of oil, especially todays oil.

Some engines don't have a oil pump. They rely 100% on "splash" for lubrication.

Dave/Geotrash: Toyotas burning oil???? Just so you know, not mine. I have a 2007 Toyota FJ Cruiser all w/aluminum gasoline 4.0L w/VVT. I bought it used w/20k miles in Jan of 2009. It now has 220k miles. It's been my daily driver since Jan 2009. Toyota recommends premium unleaded and changing the oil every 7500 miles. It has never had any fuel other than regular unleaded, and the oil and filter have never been changed at less than 10,000 miles. I've done 13 UOA on the various brands and wts of oil I've used in it. Thru UOA I've discovered it's easy on oil. I've taken its oil change interval out to as far as 18,000+ miles. It doesn't burn or leak any oil. It's never been in a shop for any reason. To date it has never thrown a code. Are there FJs out there that burn and/or leak oil? Certainly. Some folks can destroy a metal ball with a rubber hammer.

I've been discovering for the past 3.5 yrs and 5 UOA that the 6.2L L92 is completely different animal. It's very ******* the oil.

Hey Don, what do you think of Group III versus Group IV oils? I learned that around 2010, Mobil One switched from the latter to the former. I think the additives added overcome that deficiency save for being able to run the motor with no oil in it like in the old days when there was more clearance between the bearings!

 

[Geotrash]

For the remainder of an engines life there is a permanent film of oil on everything. oil clings. It's a wonderful property of oil, especially todays oil.

I've done a lot of my own research over the years on the unique characteristics of oils used in aircraft piston engines. One of the things that makes them unique is that they're designed for maximum film staying power because aircraft often sit for months between starts. All the same, operational history showed that a few engine models continued to have failures of internally lubricated parts - specifically in the valvetrain. They were the Lycoming O-320-H2AD and the Lycoming TIO-541. Both have camshafts that sit above the crankshaft, which is one part of the puzzle but not unique to those models. But, they also use a lifter design that places a higher load on the interface between the cam and the followers than other engine models from the same company. A clever lubrication engineer named Ed Kollin figured out what was really going on and designed an additive that would solve the problem.

If you have some extra time, this interview with Ed is loaded with interesting info. Even though it's focused on aircraft piston engines, obviously many of the principles of oil design are similar. One example: It's not just the water that comes from combustion that needs to be 'burned off', but also chemical compounds that are far more corrosive than water.

 

[jeremiahm]

I ran into the PF48s not being in stock and found that you can run the PF63 as well. Same filter, diameter, threads, but twice the height. More filtering media and does not hang below the oil pan. Seem to be in stock all the time as well.

 

[donjetman]

Hey Don, what do you think of Group III versus Group IV oils?

What comes to mind is that Group IV oil are preferred and more expensive than GroupIII.

If my memory serves me? a few yrs ago a law or something changed to allow GroupIII oils to be called "Full Synthetic", whereas before they were called "Semi Synthetic".

 

[Meccanoble]

I ran into the PF48s not being in stock and found that you can run the PF63 as well. Same filter, diameter, threads, but twice the height. More filtering media and does not hang below the oil pan. Seem to be in stock all the time as well.

Larger oil filter, do you think requires more oil, maybe the entire 6 qrts? All of these filters seem to be fine. I could use the longer filter for install/de-installs

 

[donjetman]

I've done a lot of my own research over the years on the unique characteristics of oils used in aircraft piston engines. One of the things that makes them unique is that they're designed for maximum film staying power because aircraft often sit for months between starts. All the same, operational history showed that a few engine models continued to have failures of internally lubricated parts - specifically in the valvetrain. They were the Lycoming O-320-H2AD and the Lycoming TIO-541. Both have camshafts that sit above the crankshaft, which is one part of the puzzle but not unique to those models. But, they also use a lifter design that places a higher load on the interface between the cam and the followers than other engine models from the same company. A clever lubrication engineer named Ed Kollin figured out what was really going on and designed an additive that would solve the problem.

If you have some extra time, this interview with Ed is loaded with interesting info. Even though it's focused on aircraft piston engines, obviously many of the principles of oil design are similar. One example: It's not just the water that comes from combustion that needs to be 'burned off', but also chemical compounds that are far more corrosive than water.

Good stuff. I sent you a DM since we're so off topic