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Bored&Stroked · 11-10-2017, 08:18 AM

Thinner oil unto itself doesn't solve all evils. Other things to consider on "modern" engines - that enable the usage of thin oil:

1) Usage of roller lifters or followers (not flat tappet)
2) Very exact manufacturing tolerances and therefore tighter bearing clearances
3) Better metallurgy and heat treating for rotating assemblies (harder journal surfaces)
4) Structurally rigid designs - block webbing, 5 main bearings on a V8, etc.. This causes less crankshaft and camshaft "deflection" - which also enables tighter clearances
5) Vastly improved oiling systems -- "priority mains" on most, good oil galley designs, dry-sump oiling systems (on many), etc..
6) Good full-flow oiling systems and filters (keeping a lot of crap out of the oil)
7) Well designed crankcase ventilation systems (some with vacuum pumps, etc) - reduces oil contamination, moisture, etc..
8) Computer controlled everything -- effective fuel/spark management leads to less oil dilution and contamination . . . which also allows the usage of thinner oils.
9) Specifically formulated oils and additives.

The only reason I bring all of this up is to help us think about the fact that "modern" engines are very different from our good ole' flatheads - they are specifically designed for modern low-viscosity oils - and they last for hundreds of thousands of miles.

11-10-2017, 08:18 AM	#12
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,070	Re: Oil pump "rebuilding" Thinner oil unto itself doesn't solve all evils. Other things to consider on "modern" engines - that enable the usage of thin oil: 1) Usage of roller lifters or followers (not flat tappet) 2) Very exact manufacturing tolerances and therefore tighter bearing clearances 3) Better metallurgy and heat treating for rotating assemblies (harder journal surfaces) 4) Structurally rigid designs - block webbing, 5 main bearings on a V8, etc.. This causes less crankshaft and camshaft "deflection" - which also enables tighter clearances 5) Vastly improved oiling systems -- "priority mains" on most, good oil galley designs, dry-sump oiling systems (on many), etc.. 6) Good full-flow oiling systems and filters (keeping a lot of crap out of the oil) 7) Well designed crankcase ventilation systems (some with vacuum pumps, etc) - reduces oil contamination, moisture, etc.. 8) Computer controlled everything -- effective fuel/spark management leads to less oil dilution and contamination . . . which also allows the usage of thinner oils. 9) Specifically formulated oils and additives. The only reason I bring all of this up is to help us think about the fact that "modern" engines are very different from our good ole' flatheads - they are specifically designed for modern low-viscosity oils - and they last for hundreds of thousands of miles.