To your engine, oil is what keeps all the various parts working together in harmony. Nothing is more important that feeding your engine with the right lubricants. Your Chevy doesn’t have to be a lost cause at 150,000 miles. We’re going to show you how to get 250,000 to 300,000 miles out of your classic or late-model by doing nothing more than using the right lubricants and changing them out on a regular basis.
What Oil Does
Lubrication performs two basic functions. It keeps moving parts from touching each other and it carries heat and corrosive contaminants away from those moving parts. Engine oil has the most intimate contact with an engine’s moving parts, including the hottest parts like exhaust valve stems and piston rings. It has to have qualities that allow it to stand up to the toughest conditions imaginable.
When lubricating oil breaks down under high-heat conditions it stops protecting moving parts, which is what leads to engine failure. Not only does engine oil keep moving parts from getting together, it also coats these parts to prevent destructive oxidation and corrosion. Additives in the oil contribute to the prevention of corrosion and the resulting deterioration. Detergents and dispersants contribute even further to prevent sludge and carbon buildup.
Sludge is something we seldom see anymore because fuels and lubricants have become more refined. Gasoline is free of lead, which caused its share of sludge. In the old days, engine oil technology wasn’t as refined either, cooking onto hot surfaces and lumping into one hot mess for rebuilders. And when the oil wasn’t changed on a regular basis it only made the sludge buildup worse.
Engines are lubricated via pressure, splash, and fog. Oil meets moving parts under pressure at the crankshaft and camshaft journals and bearings. It is also supplied under pressure at the lifters and rocker arm shafts. The layer of oil between moving parts is known as an oil wedge. The oil wedge is a liquid bearing on which moving parts ride without touching each other. Moving parts get together whenever that oil wedge is compromised.
The oil wedge is compromised whenever the engine is shut down and it has time to sit. Oil drains off of moving parts, which have time to get together. When you hit the starter moving parts have brief, direct contact until oil under pressure reaches those critical parts. Splash and fog lubrication takes time to get slung around before it coats cylinder walls, pistons, and pins. And forget lubrication at piston rings. Piston rings have direct contact with the cylinder walls, which have some lubrication but not enough. Because both the cylinder wall and the rings are typically made of iron, wear tends to be uniform in both. As the rings and the walls wear they shed microscopic amounts of metal into the oil.
Why Change Oil?
It has been proven clean oil greatly enhances engine life by protecting moving parts. You should change the engine oil every 3,000-5,000 miles, even if you’re running synthetic. We will get arguments on this one, but the cleaner the oil the better. We have seen proof of this again and again in more than 40 years of tinkering with automobiles. Changing oil, regardless of the type of oil you use, rids your engine of contaminants that can cause harm to an engine if left unattended.
Contaminants can have a corrosive effect on moving parts. Microscopic metal particles from normal wear and tear can take a toll on moving parts when they sit in the oil wedge and contact moving parts. Iron particles will score soft bearing surfaces. In fact, did you know aluminum bearing surfaces are made that way to absorb metal particles and other contaminants? Hard iron particles sink into the soft bearing surfaces, which protects the crank and cam journals from scoring. Always change the oil filter any time you change the oil.
Synthetic vs. Conventional
We spoke with Dan Peterson, Vice President of Technical Development, at AMSOIL about the choice between synthetic and conventional oil. “It depends on application and what you want from your motor oil. There are a lot of areas where it makes sense to use synthetic. And there are applications where you’re better off with conventional,” Dan comments. “For anyone who is interested in greater performance, protection, and longevity synthetics are going to do a better job.”
Dan goes on to say, “Breaking that down further, when you get into temperature extremes—very high temperatures along with very low temperatures—AMSOIL synthetics are going to provide much better performance in these extreme environments. From the high temperature side of it the base oils as well as the additives, the synergy of these elements, provides better oxidation protection, and protection from carbon buildup, which come as a result of these high temperatures.”
“From the low temperature side of it you just don’t get the flow of lubricant when you need it,” Dan adds. “The really bad wear comes when you start your engine and lubricants don’t get there quickly enough to prevent contact. Synthetic lubricants flow better at low temperatures and they tend to stay,” Dan explains. “Synthetic lubricants tend to stay, which means you have lubrication on moving parts upon start-up.”
Another option to consider is synthetic lubricants in your driveline, be it an automatic transmission or manual shift. Ditto for your Chevy’s differential, which can live happily with synthetics.
AMSOIL refines each type of lubricant it sells. AMSOIL synthetic lubricants are chemically engineered to form “pure” lubricants. These lubricants contain no contaminants or molecules that don’t serve a designed purpose. In other words, each element in AMSOIL lubricants has a specific purpose by design. AMSOIL lubricants’ uniform molecular structures impart properties that provide better friction reduction, make the most of fuel efficiency, maximum film strength, and offer extreme-temperature performance conventional lubricants cannot.
AMSOIL specializes in developing specialized synthetic lubricants that offer answers to the greatest challenges vehicles and equipment present. Extreme testing and refining are performed in-house by AMSOIL’s own people to ensure you’re getting their best effort. AMSOIL synthetic lubricants are produced and marketed for a range of automotive applications ranging from street cruising to all-out racing.
We can say with confidence that AMSOIL performs an extensive amount of in-house research and development, then tests products in real-world environments to see how these products perform. These folks push their lubricants hard in testing just to see what happens during the grueling nature of racing and extreme heat and by contrast some of the coldest temperatures imaginable.
So what to use? If you own a classic Chevy with a small-block, big-block, in-line, or V-6 it is all about using the right viscosity. The AMSOIL Signature Series 5W-50 weight synthetic engine oil is refined for older cast-iron or cast-aluminum/cast-iron combo engines with looser tolerances. It flows well at low temperatures and offers excellent protection when the heat gets turned up. AMSOIL Signature Series engine oil is available in 5W-30, 10W-30, and 5W-50. There’s also extended-change interval synthetics from AMSOIL that enable you to go for longer periods of time between oil changes.
If you own a late-model Chevy with LS power, as one example, you’re going to want to run a low-viscosity oil compatible with the tighter tolerances associated with today’s more fuel efficient engines. These engines run considerably hotter than the classics, which calls for a synthetic lubricant thin enough to overcome these tolerances and heat.
Crankshafts are made of either cast iron or forged steel. Forged steel stands up to high rpm/high horsepower better than cast iron. Cast iron, also known as nodular iron, is of a softer material. Forged steel is harder. Both cast and forged cranks must have that protective oil wedge under pressure at all times during passive or aggressive operation. Close examination here demonstrates what happens just starting an engine when the residual oil film has drained away overnight. Damage here is mild. Synthetic lubricants do what conventional lubricants cannot. Synthetics stay when an engine sits. This means protection upon engine start-up.
The proof comes when we disassemble engines that have been protected with synthetic or convention lubricants. Teardowns after 200,000-300,000 miles all demonstrate which lubricant works better.
Check out these late-model aluminum rod bearings, which tend to get hammered pretty hard. These rod bearings have 270,000 miles on them and were protected with synthetic engine oil along with regular oil and filter changes every 5,000-7,000 miles. There’s no wear. You can expect minor scoring from contaminants in the bearing and there was no wear in the crank journals.
On the other hand look at these bearings from a high-mileage engine fed a diet of conventional engine oil and infrequent oil and filter changes. Conventional oils break down at high temperatures and as they become dirty. Synthetics can stand up to temperature extremes on the order of 300+ degrees F. Conventional oils begin to break down at 260 degrees F.
Here’s a connecting rod cap and a bearing that suffered from oil breakdown and metal-to -metal contact. This kind of scoring also comes from cold starts and dry bearing/journal surfaces.
Look at these camshaft bearings. The bearing on the left is “coked up” and scored from excessive heat and inadequate lubrication. The brown color indicates the oil wedge broke down and cooked like a burnt frying pan.
A freshly machined block fitted with new pistons and rings. Piston rings on cylinder walls are where engine oil has little effect due to extreme temperatures and pressures. Compression rings ride metal-to-metal on the cylinder walls to provide a good seal against the iron cylinder walls. Hot combustion gasses blow past compression rings, which sends contaminants into the oil. This is why regular oil and filter changes are so important to engine longevity.
The crosshatch pattern in cylinder walls is there for oil control and proper ring break-in. This especially critical during engine break-in when you should be using a break-in oil.
Why change oil? Here’s one reason. Sludge this bad comes from no oil changes. It is also a product of the old days when we had leaded gasoline and poorly refined engine oils.
Engine protection should come first during assembly of a new engine. A lot of builders use conventional engine oil for assembly purposes. However, it doesn’t stay put. AMSOIL Assembly Lube sticks to moving parts and remains there for fire up.
There are misconceptions about how to use engine assembly lube. There is one truth. Engine assembly lube goes on bearings, cylinder walls, piston rings, lifters, rocker arms, and pushrods. Moly lube (molybdenum) shown here goes on flat-tappet cam lobes, but not on the journals though some engine builders do this, for proper work hardening and break-in of the cam lobes at fire-up. When you fire the engine run it at 2,500 rpm for 30 minutes for proper camshaft break-in. You can expect the oil to turn black during the break-in process, which is why it should be changed afterward.
How to reduce the amount of stray metal in the oil? There are a couple of options out there. The trick is to capture ferrous metals (iron and steel) before they can travel to moving parts. Filter Mag from Summit Racing Equipment makes metal removal from your engine oil easy. These filters hitch right onto your oil filter and they capture metal before it can flow into your engine and do damage. Here’s the Filter Mag installed and positioned at the bottom of an oil filter, which enables gravity to carry metal particles to the magnet more easily.
The Magna Filter from Australia is an inline magnet located between the oil filter and your engine. Install this guy when you install the oil filter. Clean it at every oil change.
Another option is the installation of a simple magnet at the oil pickup, which prevents stray metal particles from ever entering the oil pump.
AMSOIL SAE 30 weight Break-In Oil is formulated without friction modifiers to allow for quick and efficient piston ring seating in fresh high-performance and racing engines because it contains zinc and phosphorus antiwear additives. These additives protect vulnerable cam lobes, lifters, and rockers during the critical break-in period when wear rates are the highest. A break-in oil’s increased film strength protects rod and main bearings from damage. AMSOIL’s SAE 30 weight Break-In oil should be run for at least 1,000 miles before an oil and filter change.
Oil filters consist of filtering material folded as shown to capture contaminants down to a certain size, known as microns. AMSOIL filters feature advanced fully synthetic media that traps and holds a greater amount of small, wear-causing contaminants compared to conventional oil filters. They provide extended service intervals for increased convenience, while helping reduce engine wear. AMSOIL Heavy-Duty Extended-Life Oil Filters provide excellent filtering efficiency and high contaminant capacity for heavy-duty gasoline applications. These filters provide extended service intervals that coincide with the maximum drain interval recommendations of AMSOIL synthetic engine oils.
Here’s what’s inside a spin-on oil filter—consisting of filter material, screen, pressure relief valve, anti-drainback valve, and a heavy-gauge steel base capable of withstanding 500 psi in most applications. The anti-drainback valve is a simple silicone or rubber flap—a check valve—that allows the flow of oil one way but not the other.
When you are shopping for an oil filter, opt for a filter with the most filter material inside. When you’re in an auto parts store you can tell by weight what a filter is all about. The heavier the filter the more filter mesh there is inside. If you are serious about filtration, look to AMSOIL, K&N, Wix, and Mobil for some of the best oil filters on the market. AMSOIL oil filters are made with premium-grade full-synthetic media. The strictly controlled processing of this media ensures accurate filter construction and is what allows their oil filters to deliver higher capacity and efficiency along with better durability.
We have proven through hundreds of thousands of miles of use synthetic automatic transmission fluid builds longevity into high-performance transmission builds. We have managed to get 250,000-300,000 miles from a 4L60E with no obvious wear issues when it was torn apart as a precautionary measure. No wear on hard parts. And brand names still on the clutches and bands. Fluid and filter replacement every 30,000 miles coupled with the use of synthetics is key to transmission life.
Running a stick? Synthetic transmission fluid for manual boxes is available from AMSOIL. You may also run synthetic automatic transmission fluid in your late-model T5, TKO, or T-56 just to name a few.
If you’re running a classic Muncie M series four-speed, AMSOIL offers synthetic gear lube for these old crash boxes. It also works very well in rear axles. If you’re running a locking rearend, you’re going to want a friction modifier to keep the clutches happy and cool.
If you’d like to keep track of your engine’s forensics you can have an oil analysis performed by not only AMSOIL, but others like Oil Analyzers, which has performed this service for us in the past. Oil Analyzers evaluates the state of your engine’s oil and gives you an accounting of its wear patterns. Not only do they analyze lubricants, they can evaluate your vehicle’s coolant. Oil Analyzers personalized reports are easy to understand and include recommendations so you know exactly what you need to do in order to achieve the best care for your engine and driveline. What’s more, these folks will chat with you by phone to answer any questions.
Photos by Jim Smart and courtesy of AMSOIL