Another oil thread

Grumpy Bear · July 11

4 minutes ago, OnTheReel said:

I go where logic leads me. Fuel economy drives everything these days. Engineering and longevity is in the back seat. When the recommendation for the same engine goes from 5w30, to 5w20, to 0w20 in the course of 15 years while CAFE standards increase AND the oil change interval increases…that tells me everything I need to know. People still can’t figure out why their engine eats a cam every 75k. Really?

OMG, you think for yourself? Your doomed I say, doomed.

Google isn't my information source, it's a search engine and a pretty good one that leads me to a RELIABLE source. I can buy all the SAE and published Doctoral works of REAL experts without leaving the farm and do. It's called an EDUCATION.

As I did when I lived in the CHEVRON/Getty/Conoco/Eastman/Gulf and Several University libraries (CSM, Utah State, Iowa) printing them off for five cents a page. Learned directly from the guys who TEACH IT at Universities and more importantly to the employees of those companies. Top tier guys Chevron and others hire for this purpose. Years, not semesters of classroom work. Clueless...utterly clueless.

How much fuel, oil bright stock and light gas has this guy made? None! So how did he learn it? Same way I did. Same way Lake Speed did. In a classroom. Condescending *******.

You Reel have to stop quoting this guy. Its like feeding a stray cat. Just won't go away. :crackup:

Grumpy Bear · July 20

I just saw a teardown of a 300K plus motor where the inside was cleaner than average. The piston skirts were scuffed hard. Motor ran nice, just noisy. Piston slap. Some wear on the rod and main bearings. About right for the miles. Ring lands, specifically the oil control rings were minty fresh clean. No pin wear. This was a motor that lived on 0W20 oil and 7.5K OCI's most of its life. Bores were scored in sync with scuffing. Parts touching parts. Not a race motor. A delivery motor.

What do you think is the root cause?

diyer2 · July 20

0W20?

garagerog · July 20

11 hours ago, Grumpy Bear said:

I just saw a teardown of a 300K plus motor where the inside was cleaner than average. The piston skirts were scuffed hard. Motor ran nice, just noisy. Piston slap. Some wear on the rod and main bearings. About right for the miles. Ring lands, specifically the oil control rings were minty fresh clean. No pin wear. This was a motor that lived on 0W20 oil and 7.5K OCI's most of its life. Bores were scored in sync with scuffing. Parts touching parts. Not a race motor. A delivery motor.

What do you think is the root cause?

Would be my guess it is the 7.5K OCI. The oil that started out as 0W20 would have no where near that viscosity after that long of an OCI, especially if the engine was a GDI.

customboss · July 20

Garagerog is spot on. Add dirt ingress and constant fuel’s dilution and you get a scored up engine but relatively clean.

Grumpy Bear · July 20

30 minutes ago, diyer2 said:

0W20?

Specifically, viscosity loss. It's not so much the SAE grade as the HTHS and 100C shear loss. I've run some Honda D5Y motors past 200K without scuffing the skirts on 5W20 Red Line which has a HTHS of 3.1 which starts as the spec between a SAE 30 and a SAE 40 and stays in the 30-weight range. This fella used Klondike 0W20 which starts at 2.6 and ends as a SAE 8 to SAE16. The 100 C viscosity will follow. His motors are MPFI so little fuel dilution. But that is also a consideration. Bulk oil temp is a consideration. Shear it down, dilute it down or heat it down. Scuff a piston. So not the grade but the right chemistry for the conditions.

Note in 2015 the light SAE 40's, the HTHS values were raised from 2.9 to 3.5

Once upon a time 3.1 was the spec for SAE 30. Thus, my comments that today's SAE 30 is yester years SAE 20.

When mineral oils were what we had:

diyer2 · July 20

OK Better quality oil or shorter OCI's. As you know shorter OCI's is my standard. I would use Amsoil OE oil and go a max 5k miles. Again the long OCI's today are a joke. Hey they all sell parts and new vehicles.