Tolerances, oil viscosity, performance

[L_RAO]

Thinking out loud here...

My daily driver (2008 Civic Hybrid) calls for a 0w20 oil, and I think that's the end result of (a) a fuel economy goal, (b) tighter manufacturing / machining tolerances, and (c) the quality of the oils available.

My question is: Would it be possible to build/rebuild the NSX motor to such tolerances that then running a 0w20 oil would be fine?

And just to expand on that question: Could you take say, a 1960s V8 that requires a 20w50 oil, and build/rebuild to "modern" tolerances that it could run a 0w20 and be fine?

 

[Honcho]

Probably not. You can build to this spec on the bottom end using different rotating components, but you will run into a problem with the heads. Many of the oil passages in the heads, spool valves, LMA's and rocker assemblies were designed for 30W (or 40W in some climates). You would have to machine new parts to get it all to work.

 

[brandonsan]

My main concern would be oil leaks. I put 0w20 in my Accord and it leaked everywhere. After switching back to the recommended viscocity the leaks stopped. I think it is too thin for seals that are intended for heavier wieghts.

 

[kaede]

My main concern would be oil leaks. I put 0w20 in my Accord and it leaked everywhere. After switching back to the recommended viscocity the leaks stopped. I think it is too thin for seals that are intended for heavier wieghts.

You sure the leak stopped? Sounds highly not plausible for one oil to leak EVERYWHERE and the other to not leak at all...

 

[brandonsan]

You sure the leak stopped? Sounds highly not plausible for one oil to leak EVERYWHERE and the other to not leak at all...

I'm positive it stopped. The oil was too thin for the car but I used it because that was the only weight I could use at that time. READ THIS and look at the last statement from this oil mfr site:

http://www.eneos.us/product/1

ENEOS Products back to productsENEOS 0W-20
GF- 5 OVERVIEW
The new ILSAC GF-5 specification is an improvement in engine oil performance compared to the current GF-4 specification. The new ENEOS GF-5 oil provides better fuel economy, increased emission system durability, enhanced piston cleanliness, reduced engine sludge, and improved turbocharger protection.

0W-20 Comparison with other leading brands of 0W-20: Comparison Data

SPECIAL FEATURES
1.Low Viscosity (0W-20)
ENEOS Motor Oil 0W20 is blended from high-performance hydrorefined base oils and an optimized additive blend, so it provides much better heat and oxidation stability than regular motor oils blended from solvent-refined base oils. Thanks to its innovative formulation, ENEOS Motor Oil 0W20 achieves a low viscosity of 0W-20, so it enables excellent fuel economy and environmental protection.
2.Ultralow Fuel Economy to Protect the Environment
In addition to its high-performance hydrorefined base oils and various additives, ENEOS Motor Oil 0W20 is also blended with organic molybdenum friction reducers. As a result, the oil minimizes friction and enables superb fuel economy.
3.Meets Latest API Standards
The high-performance ENEOS Motor Oil 0W20 has been certified as meeting the latest API SN standard established by the American Petroleum Institute.
APPLICATION
Motor oil for gasoline engines.

APPLICABLE VEHICLES
Automobiles for which 0W-20 oils are recommended.

Caution: The use of this oil in automobiles designed for high-viscosity oils can result in inadequate oil circulation, oil leaks, and other problems.

 

[jond]

My fear would be the motives pushing that oil.
Is oil reco based on the engineers trying to get 500,000 miles out of the car, or is it the sales team trying to get better MPG and o2 ratings to sell more cars?
My bet is the latter.

Second, a car that pushes high Gs in the corners, and revs to 8,xxx rpm needs different oil than a car targeted at normal drivers.

Third, based on my research, oil loses around 10points of viscosity after 1,500 - 2,000 miles. AKA, I wouldn't be surprised if a 0w20 doesn't turn into a 0w10 after 1,500 miles.

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