The Squeaky Wheel: A Brief History of Automotive Lubricating Systems

The origins of vehicle lubrication systems predate not only the internal combustion engine, but the utilization of refined petroleum by thousands of years. From tallow and rapeseed oil, to mineral oils and refined petroleum splash systems and onward to wet and dry-sump pressure-fed oiling systems, preventing moving parts from wearing holes in each other has been a problem since the invention of the wheel. 


It's 1848 and you're aboard a wagon traveling westward. You haven't seen a Jiffy Lube on the trail yet and it's about time for a lube and tune on the old 'Stoga. Instead, hanging from the side of your wagon is a bucket of tallow - a greasy compound rendered from animal fat. Every few dozen miles you slather a brush over your axles to keep them in working order, lest they break and you die of dysentery.

The only thing harder to find than a Jiffy Lube was a Flying J to top up on bullets, jerky, and diesel.
Photo credit Curt Mekemson, http://wandering-through-time-and-place.me/

"I don't know about you guys but I could really use a Gatorade"

At the same time, hundreds of miles away, a steam locomotive puffs away on the new Albany and Schenectady Railroad. Just before departing the engineman drops a lump of tallow down the blast pipe which melts within the steam and lubricates the pistons and valves. Citizens marvel at the new technology and wish in vain that someone would hurry up and invent the beverage car before they choke on burned coal particulates. 



A few years later rapeseed is planted in large quantities in order to harvest the plants' natural oil. Like tallow, it is a good lubricant that resists washing away and becomes the chief lubricating oil used in steam engines. A decade later, Col. William Drake finds oil in Pennsylvania, igniting the oil industry. With the addition of a little science and American greed, oil refinement is developed and competitive petroleum lubricants emerge.

A little while later, Henry Ford tires of being pedestrian and starts production at his plant, amassing a fortune and popularizing one of the most-utilized and longest lived inventions of the 20th century: the automobile. With that step achieved, the focus now falls on the development of the automobile-specific lubricating system.

The little dipper was un-"bear"-able to consumers.

The first Model T, like many industrial engines at the time, utilized a splash system to lubricate the bearings within. The system was marginally effective: as the rotating assembly spun, small cups attached to the connecting rod caps scooped oil from the sump at the bottom and flung it about the crankcase, in a shotgun approach to lubrication. Because oil was not directed in specific places or pressurized in any way and lubrication efficacy was susceptible to oil slosh, bearing life was short.

Soon after gleefully oblivious consumers started grenading engines determining who could race to the top of the local hill first, pressurized oiling systems were developed. By extracting mechanical power from the crankshaft, a small pump could direct oil to the most critical areas - the crankshaft mains. This allowed more precise metering of oil to important parts and increased longevity and reliability, making it less likely (though not impossible) that driving up a hill or through a bend would reduce your engine to a pile of slag. Partially pressurized systems used jets of oil to allow improved oil splash, lubricating cylinder walls, connecting rod journals and valvetrain components. 

Cross-drilled Honda D16 crankshaft, allowing oil to the rod bearings

As manufacturing technology advanced, systems were more fully fed by pressure systems. Grooved bearings and oil passages drilled within the crankshaft and rods allowed pressurized oil to flow to all bearing surfaces, including the camshaft and wrist pins.

The addition of this extra hydraulic circuit within the engine opened up design opportunities immensely. Pressure fed bearings could now operate in a hydrodynamic mode, greatly reducing bearing wear. Cooling, one of the primary functions of the oil system, was vastly improved by directing oil to high-wear surfaces and the underside of the pistons. A pressure fed system could direct oil through an external heat exchanger, allowing for temperature regulation of the system and operation at optimal temperature, prolonging oil as well as engine life.

Hydraulic valve tappets automatically take in slack, or lash.

The impact of the pressurized lubrication system goes beyond engine wear. The hydraulic power was harnessed to develop valve tappets which self-adjusted, greatly reducing the maintenance required on the valvetrain. Having a hydraulic circuit on-board the engine enabled usage of actuators which dynamically changed camshaft timing, improving fuel economy and power at the same time. Available oil pressure can even be utilized in cylinder deactivation systems, improving economy.

Even with these improvements in the oiling system, they still fail in extreme situations. Just like the first motorists racing their Model T's up the nearest hill (often in reverse, due to gravity-fed fuel starvation issues,) modern cars can suffer the same fate under extreme g-forces. 

I'm stuck on Band-Aid brand cause dry-sump costs a fee

Most passenger cars utilize a wet-sump oiling system. This system has a sump (or pan) under the engine which holds oil. The engine is designed to allow oil to drain back to the sump where it is then drawn into the oil pump. Under vigorous maneuvers, oil can slosh away from the pump inlet and into the rotating assembly, causing windage losses, increased oil consumption and aeration and, if you're having a bad day, total starvation of the oil pump.This is mitigated by the use of windage trays, oil scraper screens and trap doors within the oil pan, but these are, at best, a band-aid. 

For a hefty price, you too can own 1940's technology!

For the most resistance to high-G maneuvers a dry-sump system is preferred. Instead of allowing the oil to accumulate inside the crankcase, suction pumps draw engine oil from key locations as it is expelled by various bearings and orifices. By utilizing multiple stages, oil is drawn immediately from the engine at various locations into an external sump or tank. Since this tank has increased flexibility of design, it is much less likely to be affected by constant or transient high-G maneuvers. These systems were pioneered for the use in dogfighting WWII aircraft. Because of the high performance of these aircraft as well as the potential for inversion, wet-sump systems were unfeasible. These designs transferred well to automotive racing, and dry-sump systems are preferred for almost all reasons except one: cost.

Ultimately, pressurized systems led the way to the top of automotive performance, but it all started with a tub of lard stuck to a rickety wagon, carrying choleric people between hunting mini-games, oxen-killing rivers, and pixelated landmarks.

Definitely number 3.

References and further reading:

http://www.alexdenouden.nl/08/lubri.htm
http://www.copper.org/applications/industrial/bronze_bearing.html
http://www.waybuilder.net/sweethaven/MechTech/Automotive01/default.asp?unNum=5&lesNum=3&modNum=13
http://www.palco.co.in/history_of_lubricants.html
http://www.hotrod.com/thehistoryof/retrospective/hrdp_1210_vintage_ford_model_a_b_c_four_cylinder_engines/
http://en.wikipedia.org/wiki/Oil_pump_%28internal_combustion_engine%29
http://en.wikipedia.org/wiki/Dry_sump
http://wandering-through-time-and-place.me/