If you're like us, you work on your Mopar yourself, performing oil changes and other routine maintenance in the garage or driveway where you live. And while accomplishing such work can be rewarding, a trip to the auto parts store to select the oil for your car can be a frustrating experience. There are literally hundreds of oil types, brands, and viscosities to choose from these days, and picking the right one for your car depends on many factors. This month we'll try to simplify things for you a little, and give you the information you'll need to choose the right lubricant for the engine in your Mopar.
Choosing engine oil used to be easy; you'd just take what you could get at the local gas station. They'd even put the oil in for you back then. Engine and oil technology have evolved since our musclecars were built, is your engine oil keeping up with the times?
Why Worry About Oil?
Much like the heart and blood of the human circulatory system, the oil pump and oil in your engine is critical to the engine's life expectancy. Engine oil serves three distinct purposes, and must do each very well to offer the maximum protection and performance. First, pressurized, sprayed, and residual oil lubricates critical internal engine components, preventing metal to metal contact and wear. Next, the oil cools the engine, trapping heat from hot spots like the valve guides, pistons, and rod bearings, and dissipating it through contact with cooler areas such as the oil pan. Thirdly, the oil cleans the engine by suspending contaminants that are removed through filtration and oil changes, keeping the engine free from deposits and protected from corrosion.
Choosing the right lubricant for your engine is critical for maximum performance and durability. Are you using the right engine oil in your motor?
Technology has certainly evolved since the invention of the automobile, and this evolution is no more apparent than in one of the most technical parts of the car, the engine. Today's automotive engines offer great power and durability, while using a fraction of the fuel, and creating a fraction of the emissions when compared to musclecars of the past. While modern electronic fuel injection is responsible for some of these improvements, accurate machining and modern internal engine parts account for a portion of this efficiency as well, allowing the use of thinner oils to promote power. And although the engines in our Mopar muscle cars are still pretty old, the rings, bearings, seals, and machining techniques used to rebuild them are more like those utilized in cars manufactured today, so a modern engine oil might be a better choice for your older car.
Luckily, most catastrophic engine failures are not caused by using the improper oil, but rather due to oil starvation. No type of oil can compensate for an inadequate or poorly maintained oil system or for a worn out engine, so the first step in ensuring engine durability is to have a healthy engine, the proper oil capacity, and sufficient pumping power for the intended use of your engine. A windage tray and high capacity pan will help prevent oil starvation, and for racing engines the oil pan should have acceleration, cornering, and braking baffles or an aftermarket pan. So assuming the oil system of your engine is adequate for the intended use and operating properly, your engine probably won't fail catastrophically regardless of which oil you choose.
An adequate oil supply is critical to your engine's life expectancy, so an aftermarket pan should be in your rebuild budget. Alternatively, some factory HP Mopar oil pans offer increased capacity and baffling as well.
Though oil selection generally won't cause your engine to blow up, choosing the right oil can affect horsepower, and will definitely determine how long your engine will last. So if you plan to keep your car for a while (and who doesn't) choosing the proper oil can ensure that your engine will perform well and last a long time, and can even keep costs down when the time comes for a rebuild. So now that we know a little more about the purposes of engine oil, let's discuss what engine oil really is and the different types you might choose for your car.
What is oil Made of?
No matter what brand of oil you use, the bulk of the oil is comprised of a base stock, which can be petroleum (crude oil), synthetic, or a blend. Various chemicals are then added to the oil to provide anti-wear, anti-foam, corrosion protection, neutralization of acids, maintenance of viscosity, detergency, and dispersancy properties. These chemicals are called the additive package, and depending on the oil they can simply meet, or far exceed the requirements of the American Petroleum Institute (API).
Petroleum Based Oils
These engine oils are called conventional oils and use petroleum that has been refined from crude oil as their base stock. An additive package of chemicals is then added to the oil, giving it the proper active ingredients to protect and lubricate your engine. These oils perform well in most automotive applications, and are relatively inexpensive to manufacture because they use natural crude oil as a base stock. A drawback with conventional oils is the limited capacity of the base stock to lubricate critical components and carry particulates as the oil ages, and the breakdown of the oil's shear strength with heat and over time. For these reasons, oil changes should be performed more frequently when using conventional motor oil.
Petroleum Based Oils
Synthetic Oils
Synthetic Engine oils are made from a base stock that is synthesized from relatively pure chemicals for specifically designed performance characteristics. While this does increase the cost of the base stock, thereby increasing the cost of the oil, the benefits can be great. Synthetic oils offer superior low temperature flow, getting to critical engine parts quickly on startup and especially during cold starts to prevent engine wear. Synthetics also generally respond better to additive packages and are engineered with a greater capacity to lubricate under extreme heat and pressure conditions, so they offer superior wear protection. Synthetics can reduce engine deposits, reduce oil consumption, improve fuel economy, and will definitely make cold-starts easier if you live in a cooler climate. Jet engines use synthetic oils exclusively, so there is definitely a proven advantage to synthetic oils. So if you don't mind spending a little more when it comes time for an oil change, using synthetic motor oil will protect and lubricate your engine better, with a longer service life than conventional oil, meaning fewer oil changes.
Synthetic Oils
Synthetic Blends
Just like the name sounds, a synthetic blend or "semi-synthetic" engine oil is simply a mix of conventional and synthetic base stock. While this type of oil does offer many of the benefits of full-synthetic oils, it also has the drawbacks of conventional oils. We generally feel that the middle of the road price of synthetics equates to middle of the road performance, but if you feel your engine needs some of the benefits of synthetics without the cost of full-synthetic oil, a synthetic blend might be right for your engine.
Synthetic Blends
Viscosity
The viscosity of engine oil is the oil's most important property, and the term viscosity refers to the oil's resistance to flow. Since the engine oil must be able to flow to engine parts when the engine is started in cold conditions, and must also remain viscous, or "thick", enough to lubricate the engine at high temperatures, a good property of engine oil is to have minimum viscosity change for a given temperature change. The Society of Automotive Engineers (SAE) Viscosity Grade is a system based on a variety of tests, resulting in 11 distinct SAE grades of motor oil.
The viscosity of an engine oil is represented in numbers, in this case "10W40". Which viscosity oil is right for your Mopar's engine?
While the engineering term defining an oils range of operating temperature is called the viscosity index, the SAE grading system simplifies things slightly, offering a cold, and hot performance rating, typically depicted as "10W40" or a similar number. In plain terms, you can think of the "W" in this rating as "Winter", and the number prior to the W indicates the cold weather performance of the oil. The larger number after the W indicates the high temperature performance of the oil. So simplified, the lower the first number, the colder weather the oil will perform in, and the higher the second number, the better the oil will perform in high-heat and high-load situations.
Choosing the correct grade oil for your engine can be as simple as looking in the owner's manual, but more often depends on how and where you drive your car. In colder climates, a low first number in the oil grade will give you superior flow and protection during cold starts, but if you drive your Mopar aggressively you'll likely still need the protection of a higher second grade number. Conventional oils are limited, and generally synthetics will offer a wider spread, or wider viscosity index, for better all-temperature protection. Another consideration is the power it takes to move the oil through the engine. Since thicker oils take more power to pump, using the thinnest oil that gives adequate oil pressure can make more horsepower available to the rear tires.
Amsoil's website also offers a chart recommending SAE viscosity grades for given operating climates. In general, the colder the climate, the thinner the oil needs to be to flow during engine start.
Special Consideration For Flat-Tappet Camshafts
While we could dedicate an entire article to choosing the appropriate oil for an engine equipped with a flat-tappet camshaft, in this article we'll give you the basic information you need to protect your engine's cam and lifters. As engines have evolved over the years, so has oil technology, and so have the government regulations governing what additives can be added to engine oils. As a result, the amount of zinc and phosphorus in modern engine oils is often inadequate to properly protect a flat-tappet camshaft and lifters. For these reasons, you should pay special attention to the oil used during engine break-in, and also to the oil you run day to day in a flat-tappet cam equipped engine. Racing oils, such as Valvoline VR1, and synthetics, generally contain more of the necessary additives than off-the-shelf oils from your auto parts store, and for break-in we certainly recommend an additive like Comp Cam's break-in lube.
Automobile manufacturers almost exclusively utilize roller camshafts these days, and engine oils just don't have the additives needed to protect our older flat-tappet camshafts.
Realizing the need for higher zinc content in oil, manufacturers such as Brad Penn, Comp Cams, and Joe Gibbs Racing have developed "race only" oils that don't necessarily meet government regulations for street use, but do contain the additives needed to protect your flat-tappet camshaft. So if you want the ultimate protection for your solid or hydraulic flat-tappet camshaft, and you don't drive your car on public highways, one of these oils may be right for your application.
It's a fact that today's oils contain less zinc to protect flat-tappet camshafts, so during break-in we recommend using an additive like Comp's break-in lubricant. There are also "racing use only" oils available from Brad Penn and Joe Gibbs racing that will help protect your flat-tappet cam and lifters.
