There is no way to absolutely guarantee that your cherished collector car is going to last forever. However, it is very possible and actually fairly easy to take care of your pride-and-joy in such a way that you can just about prevent all wear and tear of the mechanical portions of your cruiser.

• MOTOR OIL LUBRICATES YOUR ENGINE:
  
  Motor oil lubricates the inside surfaces of an engine, allowing the various parts to move freely and to prevent metal from wearing away metal. To do this job well, the oil must be viscous enough to prevent metal-to-metal contact, yet not so viscous that it is difficult for metal parts to move freely. How viscous an oil is, also called its viscosity, is simply a measurement of the oil's resistance to flow. Oils that are thin and flow easily are said to have a low viscosity, while thick oil that does not flow easily has a high viscosity. The S.A.E. (Society of Automotive Engineers) uses a numbering system to rate a motor oil's viscosity. Lower numbers (like 5) designate lower viscosity (less resistance to flow), while higher numbers (like 30 or 50) designate higher viscosity (more resistance to flow).
  
  
• MOTOR OIL COOLS YOUR ENGINE:
  
  Motor oil also helps to cool an engine by carrying away the heat created by the friction of moving parts, as well as the heat generated by the process of internal combustion. The anti-freeze/coolant mixture used in a vehicle's cooling system cools only the upper 2/3rds of a typical engine, which includes the valves, the cylinder heads and the cylinder walls. The lower third of the engine - the crankshaft, the main bearings, the connecting rod bearings, the camshaft and its bearings, timing chain and gears, and the pistons- must all be cooled by motor oil, which transfers heat to the crankcase. This heat transfer by oil is crucial to the operation and long life of your engine. Valve train components, pistons and other parts can reach temperatures of 600 degrees (F) or more! If not dissipated by your motor oil, this heat can travel down the connecting rods to the main rod bearings, which can soften and melt. Failed rod bearings are a very costly repair. Motor oil can perform this cooling function only if the level is high enough, and if the engine's passages are clear of deposits that could impede the flow of the oil. The extra-capacity, high-performance oil pans that are used on those big-cube torque monsters allow extra oil in the system which will in turn allow the oil system to remove even more heat from the engine.
  
  
• MOTOR OIL KEEPS YOUR ENGINE CLEAN:
  
  Motor oil helps to keep an engine clean by holding dirt, combustion contaminants and tiny metal particles in suspension so they can be removed with the old oil and oil filter at each oil change. It is very important to remember that although motor oil is designed to help keep a clean engine clean, the detergents and other additives present in motor oil are not sufficient or designed to clean a dirty, poorly maintained engine. An oil and filter change every 3 months or 3,000 miles is one of the best ways to keep a clean engine clean and healthy, ensuring long life.
  
  
• MOTOR OIL SEALS YOUR ENGINE:
  
  Internal engine metals have tiny surface irregularities and the sealing qualities of motor oil is needed to fill in theses microscopic gaps, promoting better compression and combustion efficiency, and improved performance. As motor oil becomes contaminated, fuel-diluted and generally unfit for continued use it loses this sealing ability. Prolonged use of dirty, contaminated motor oil reduces performance, economy and dramatically shortens the life of your engine due to a loss of lubrication. Carbureted engines that are not operated on a regular basis, like our occasional driver collector cars, are particularly sensitive to the problem of fuel-diluted motor oil. The overly-rich operating conditions of a typical carburetor, as compared to modern fuel injection systems, tends to dump a larger amount of raw gas into the oil system during choke/ warm-up operation. Infrequent driving will not provide the circumstances necessary to fully burn this unwanted gas from the oil. To compound the problem, an oil filter is designed to trap particulate matter, not liquid contamination and therefore can have no effect in helping to remove unwanted gas from your oil. For the average muscle-car owner, an oil change every 3 months regardless of the mileage accumulated will return the best protection for the engine.
  
  
• THE ADDITIVE PACKAGE IN MOTOR OIL PROTECTS YOUR ENGINE:
  
  All modern motor oils contain additives that help to protect the internal engine surfaces from the extremely corrosive acids and combustion by-products that are the natural result of the normal operation of an engine. Some of theses additives actually adhere or bond to certain high-friction engine surfaces, most notably valve-train and cam-lobe areas, creating a sacrificial barrier against rapid wear due to the extreme pressures under which these components are designed to operate. Over time, these additives become used-up, or depleted and can no longer offer the protection that an engine requires. When the fresh motor oil is added during an oil change, the additive package is replenished which helps to increase the life and overall performance of your engine.

Oil Viscosity High-performance Muscle-Car engines, as well as typical 20-30 year old collector car engines operate under such a wide range of temperatures and conditions that an oil of a single grade, or weight cannot possibly give your engine the high level of protection that a modern multi-grade oil can deliver. The older, single-grade oils have a designation such as S.A.E. 30. The natural tendency of oil is to thicken up or become more viscous at lower temperatures. Conversely, it will thin out, or become less viscous at higher temperatures. Specifically, any oil that may be of an acceptable viscosity at normal operating temperatures may be far too viscous at lower temperatures, creating excessive engine wear. And of course, any oil that is suitable for start-up or lower operating conditions will become far less viscous at the higher operating temperatures that our engines produce, and offer virtually no engine protection. It is exactly this property that prevents single-grade motor oils from offering your engine the high level of protection under all operating conditions and temperatures that a modern multi-viscosity oil can deliver.  

Sometime around the late 50's and early 60's, Multi-Grade or Multi-Viscosity motor oils were introduced that provided much improved engine protection as well as better performance and fuel economy. A multi-viscosity oil can be thought of as being two different types of oil in the same bottle. Through improved refining methods and, and the use of very special and specific additive packages, the oil manufacturers have been able to produce oils that have the properties of two completely different viscosities, depending on the temperature of the oil. 

The most popular and widely used oils in classic muscle cars and collector cars are designated 10W-30 and 10W-40. There are many other multi-viscosity oils available ranging from 0W-20 and 5W-30, all the way up to 15W-40 and 20W-50. The first number in a multi-viscosity oil refers to the oil's viscosity at cold start-up, which describes any engine that has not been run for at least 4 hours. Notably, this has absolutely nothing to do with the outside air temperature. At these relatively low temperatures, the oil is thin enough to be easily and quickly pumped up to the critical parts of an engine, giving improved protection at these low temperatures. Once the oil has reached its normal operating temperature (150- 190 degrees), chemical additives in the oil called long chain polymers react to the heat and help to give the oil the properties of a higher viscosity oil, protecting the engine at these higher operating temperatures. No matter how old or how many miles are on your collector car's engine, if it is in relatively good mechanical condition, there is absolutely no viable reason to continue to use a single grade oil. Single-grade oils simply cannot deliver the performance and protection that is available to you with a multi-grade oil.

Motor Oil Additive Packages

20-25% of every quart of modern motor oil is comprised of additives. The properties of motor oil alone are not enough. Your cruiser's engine would self-destruct in a short amount of time were it not for these additives. Most popular, well-known oil companies develop their own unique additive package to meet a specific and exacting level of performance. Theses additive package recipes are closely guarded company secrets, as this is what gives each brand of motor oil its unique personality. The combination of the mineral-oil base stocks and the additive package is what is referred to as motor oil, and they are all designed to meet a minimum level of acceptable performance standards. These standards are set by the A.P.I. (American Petroleum Institute), and the rating system has been given a system that relies on letters, as opposed to the numbering system that the S.A.E. utilizes for the viscosity ratings. The A.P.I system has two separate categories, one for gasoline powered engines and one for diesel powered engines. The two-letter rating for gas-engines always starts with the letter S, followed by a letter that denotes the level of performance that oil is designed to achieve through the use of additives. Diesels are much the same, with the first letter always being a C. 

This rating system was first put into use in 1962, when the very first additive was put into motor oil. The rating for this oil was 'SA'. By the way, for you trivia nuts out there, the very first additive to be put into motor oil was detergent. As the years went by, and the performance level of motor oils were increased through the improvement of the additive packages, the ratings were updated simultaneously. Today's motor oils intended for gasoline engines are all currently rated at a level of 'SL'. This is a 'superseding' system, meaning that an older engine, just like the engines in our classic cars, will greatly benefit from the use of any higher rated oil than what was required for it at the time of its manufacture. However, a newer vehicle cannot use any oil with a lower rating than what is required for it. Fortunately, whenever the A.P.I. sets a new performance standard for motor oil, the oil companies have no viable reason to continue to manufacture or market the lower rated oil. Consequently, there is very little chance of you ever finding for sale, much less actually using any old, outdated oil.

The most common additives in motor oil:

• ANTI-WEAR AGENTS
  
  These additives, commonly zinc and other low-friction substances, react chemically with metal surfaces to produce a protective coating in high-load areas such as cams, lifters, valves and rockers, where the protective oil film might otherwise break down.
  


• DETERGENT/ DISPERSANTS
  
  These are added to the oil to prevent sludge and varnish formation, the leading cause of engine wear and failure. They pick up microscopic engine contaminants and hold them suspended so they can be removed with the old oil when it is changed.
  


• RUST AND CORROSION INHIBITORS
  
  Formulated to neutralize the acids formed by condensation and contaminants, these additives prevent rust and corrosive wear on engine surfaces.
  


• OXIDATION INHIBITORS
  
  At high temperatures, oil oxidizes rapidly and dramatically loses its ability to lubricate. These additives prolong oil life by preventing oxidation, the chemical reaction of oxygen and oil that can thicken oil excessively, form sludge and varnish, which can cause ring sticking, corrode bearings and many other problems.
  


• ANTI-FOAMING AGENTS
  
  Additives that break down the foam that is whipped into the oil by rapidly moving parts. Foaming reduces the oil's lubricating and cooling capacities, promotes oxidation, reduces oil pressure, produces air pockets, and can even cause oil to overflow the crankcase.
  


• VISCOSITY-INDEX IMPROVERS
  
  These are the 'long chain polymers' mentioned earlier that un-coil at high temperatures helping to reduce the thinning of the oil. They also prevent the over-thickening of the oil at low temperatures, allowing the oil to work more effectively throughout a wider range of temperatures.
  


• FRICTION MODIFIERS
  
  These additives further minimize friction between the moving parts of the engine. This helps the engine to produce more useable power and improve fuel economy.

These are not all the additives that are used in modern motor oils, but they are the most common ones. Unfortunately, these additives do not continue to work indefinitely. The actual mechanical shearing action of the engine's internal moving parts have a tendency to break up or shear additives. Oils that resist this shearing action are said to have a high shear stability.

Contrary to popular belief, motor oil does not wear out. The chemicals that make up the actual oil itself cannot be changed, meaning that the oil will always be oil. However, after prolonged use, the oil does become overly-contaminated and the additive package does wear-out and can no longer be effective in protecting your big-dollar engine. The shearing action of the engine, along with the ever-increasing level of contaminants present in the oil due to combustion cause the oil to become unfit for continued use. If left in the engine after its usable life, severe wear and tear results in dramatically shortened engine life. Fortunately, the single most effective maintenance procedure that be performed on any vehicle is also one of the least expensive. A simple oil and filter change every 3 months or 3,000 miles will reward you with a long and trouble-free engine life.

Which Oil to Use?

With the proliferation of so many different types of motor oil on the market today, how do we know which oil is the best for our engines? Well, there are a few general answers to that question.

First of all, if the engine in your classic car is basically all original and stock, then you should probably just use the type of oil that was recommended when your car was manufactured. However, if for example, a straight 30 weight oil was recommended when it was new, you will definitely derive some benefits from using a modern 10W30 oil instead. Never substitute a multi-viscosity oil who's second number is lower than the straight-weight oil's number. For example, don't use 50W-20 in place of straight 30 weight. The hardest old wives tale for most to overcome is thinking that thicker is better when it comes to oil.

Actually, just the opposite is true. Thicker oil is harder for your engine to move around, which takes more power. This in turn creates more heat, which creates more friction and wear and tear, along with less power and economy. A thinner oil moves through your engine easier and with less energy, providing better overall protection and economy, especially at cold start-up, where more than 50% of all engine wear occurs. Of course, you never want to use too thin of an oil. That would cause excessive wear at high temperatures. Unless your engine was specifically designed for it, and as long as it is in reasonably good mechanical condition, there is no reason to use the heavier oils, such as 20W-50.

Good quality oil, frequent oil changes and a quality oil filter at every change will keep that old hot-rod burnin' rubber for many years to come!




Kit Sullivan is a 15+ year automotive lubrication engineer and a classic and muscle car enthusiast and collector