About the only attention most people give to engine oiling is a fresh filter and four or five new quarts of 10W-40 every couple thousand miles. For serious engine builders, however, the intricacies of an engine's lubrication system are something to puzzle over. We scheme to make it work better and take less of a toll on the output at the end of the crank. The masses may think we're nuts, but engine oiling is both a matter of survival and making maximum power.
We've often heard that the right oil pan and accessories like windage trays and crank scrapers can be worth considerable power in certain applications, and we recently experienced this firsthand during a dyno-test that wasn't going our way. A previously baselined engine was suddenly down about 20 hp after sitting on the shelf for a few weeks. After some head scratching, our sharp-eyed dyno operator drained about a quart and a half of oil out of the pan, and the power came back. It turns out we poured one too many quarts into our stock 5-quart pan. That's just one example of power being robbed by an oiling system.
Gearheads like us think about lubrication in terms of windage, control, and delivery, while those outside our world think about earning a free car wash coupon with an oil change. The lubrication concerns covered here are for guys like us; let the masses read about miracle diets and Jennifer Aniston.
What it is: Oil pumpWhat it does: The heart of the lubrication system, the oil pump delivers oil to the galleries to supply the engine's internals with precious lubricant
Features: Unless you have a splash-lubed '20s Marmon, you need an oil pump. But what should you look for? The most commonly confused aspect of pump performance is the relationship between volume and pressure. These may be separate attributes, but they are intrinsically linked. To maintain a given oil pressure, a given volume of oil flow is required. How much flow is necessary depends on the engine's internal clearances, or in a sense, how quickly the pressurized lube is fed in versus how quickly it bleeds past the engine's internals. Loose clearances represent a greater pressure leak and result in a lower oil pressure. Increased pump capacity (volume) will maintain a greater pressure level under the same conditions. The pressure will also vary according to the viscosity of the oil-the thicker the viscosity, the higher the flow resistance and the slower it will bleed through the system.
A properly matched pump normally has more volumetric capacity than the engine needs, and it will therefore build excessive pressure if unregulated. The excess capacity of the pump is normally bypassed via a built-in spring-loaded regulator assembly. The pressure level is controlled by bleeding off a portion of the excess volume either back to the feed side of the pump or to the sump. Under some circumstances, excess pressure can be produced if the bypass circuit has insufficient flow capacity. Often this is the case with a cold engine running thick, heavy oil. The cold oil can't be bypassed fast enough to keep the pressure down, particularly as oil pump speed and output volume increase at high rpm.
Comments: Production oil pumps are primarily of two designs-the plain spur-gear pumps common to many GM engines including big- and small-block Chevys, and the gerotor pumps found in Mopar engines among others. Gerotor pumps are superior in capacity, efficiency, and stability. Spur-gear pumps are adequate for most performance applications, but there's a high-frequency pulsation or chatter inherent in their design that transfers via the oil pump drive to the distributor and camshaft. Racing mods include relieving the discharge port to lessen the change in discharge-port area open to flow as the pump's driven gear rotates. Anti-chatter grooves are often cut into the pump body and cover to reduce the pulsating effect. Racing pumps are available that incorporate some of these design considerations.
The gerotor design is favored for all-out racing engines. These pumps take less power to drive for a given capacity and provide both superior suction and delivery. High-end aftermarket gerotor pumps are available from specialty manufacturers for popular applications.
Bigger is not necessarily better when choosing an oil pump for a given application. Excess capacity will simply be bypassed and recirculated, robbing power and unnecessarily adding heat to the oil. It is best to realistically assess the anticipated oil requirements of the combo and use enough pump to do the job without overkill. The major pump suppliers are more than happy to make pump recommendations based on the intended use and rpm range of the engine.
Installation: It typically bolts on in place of the stock pump. Specialty pumps may require a matched oil-pick-up tube.
Price: Stock replacement pumps run between $16 and $50, with high volume pumps only a few dollars more. Race pumps run the gambit from about $50 for a production-style piece, to several hundred for a billet gerotor unit.
What it is: Oil pan pickupWhat it does: Connects the oil pump to the oil supply and screens large debris
What it's for: Every engine needs a pickup. Most aftermarket pans have one or more pickups that must be used with a specific pan configuration.
Installation: Some, like on the Chevy small-block, which is a press-fit, should be tack-welded; others bolt on in a more secure manner. Make sure the pickup inlet is located the recommended distance from the sump floor (typically about 31/48 inch). Maintain an airtight seal between the pickup and pump. A pickup air leak above the oil level can be the kiss of death in a racing application.
Comments: A pump's efficiency is much greater on the pressure side than on the suction side. No matter how good the oil pump may be, if it is not getting an adequate supply of oil on the suction side, the system performance will be compromised. Insufficient or restricted suction can cause cavitation in the pump and will greatly reduce its oil delivery capacity. Select the appropriate suction system for the application. Most of the factory systems are adequate for street or mild race use. For more serious racing or high-rpm applications, some engines such as big-block Mopars are routinely fitted with larger-diameter pickups. Likewise, small-block Chevy pumps are available from Milodon or Moroso with 31/44-inch pickups for applications that require them. High-rpm race engines with external pumps, such as big-block Mopars or AMC V-8s, are frequently fitted with external pump-feed systems like the Milodon Mopar system (shown) with minimum pump inlet restriction.
Price: Replacement pickups go from $7 to $20, while pickups for aftermarket pans typically sell for $30 to $50. Complete dual-line-feed external pickup systems with pumps run about $500.
What it is: Windage trayWhat it does: Keeps the spinning crank separated from the pool of oil at the bottom of the sump. In a wet-sump system, oil can quickly wrap around the crank, costing big power through windage losses as engine rpm rises. With a stock-type or street sump, the oil is in close proximity to the crankshaft and oil splash is inevitable. A tray will reduce the amount of oil getting to the crank and help limit the amount of oil that gets caught in the rotating assembly where it can cause power-robbing parasitic drag. The windage tray directs oil away from the crankshaft, while minimizing the oil reaching the rotating assembly from below. There are several styles of trays available. The most common is a sheetmetal baffle with louvers positioned to enhance drain-back. Some are also built of perforated mesh or screen. Both styles, from Milodon, for a small-block Chevy are shown on the previous page.
What it's for: A tray benefits the performance of practically any engine by improving oil control. Besides the potential for increased power through diminished windage losses, reliability at high rpm is also enhanced, since the tray helps keep oil from getting up in the crank instead of in the sump where the oil pump needs it. Some high-end race pans are designed with baffling and built-in windage-control and should not be run with a separate windage tray.
Installation: Some trays sandwich between the pan and block, but most bolt over the main caps with either a special cap screw, or a stud kit designed to accommodate the tray. The clearance to the rotating assembly must be checked (typically 0.100 inch minimum) and adjusted as required.
Price: Trays start at just over $20, with most in the $50 range, and more elaborate designs at about $100
What it is: Crank scraperWhat it does: Some oil will always cling to the spinning crank, and a crank scraper is a simple device to strip the bulk of it off. Mounted to the passenger-side pan rail, the scraper is a sheetmetal shroud matched closely to the profile of the spinning crank and rods. As the counterweights and rods come past, the scraper deflects the bulk of the oil clinging to the rotating components.
What it's for: Properly installed, a crank scraper is another tool to improve oil control that can equal cheap gains in output in even a moderate-rpm street/strip application
Installation: The scraper bolts onto the block at the pan rail on the passenger side of the engine. Crank scrapers generally must be custom-fitted and profiled for about 0.045-inch clearance to the crank and rods. A die grinder is the best tool for the profiling.
Price: About $10 retail and a few hour's work to fit it
What it is: Hardened oil-pump drive
What it does: Transfers the drive torque from the camshaft/distributor gear to turn the oil pump
What it's for: In a performance application, the stock oil-pump drive can break with disastrous results. Performance drives are made of hardened chrome-moly steel to minimize the potential for failure. Some have non-stock drive arrangements to match specific performance oil pumps, such as hex-drive Chevy small-block drives to replace the weaker stock slot drive. Shown here is a Milodon 440 drive with a bronze gear for use with a roller cam.
Installation: Like the stocker
Price: Under $20 for a Chevy- or Ford-style drive, to over $100 for units that carry a gear
What it is: Lifter-valley baffle
What it does: Keeps hot oil from splashing the underside of the intake manifold. It also prevents lifters from flying out of their bores in the event of a valvetrain failure, which can uncover the oil gallery and result in a loss of oil pressure and lead to engine failure. Not a mandatory item, but in some cases it's a worthy addition.
Installation: Drilling and tapping is required for the mounting bolts
Price: $30
What it is: Pan baffle
What it does: Mounts under the oil pump on a Chevy V-8 and keeps the oil from climbing the rear of the pan and getting caught up in the crank under hard acceleration
Installation: Sandwiches between the main cap and oil pump
Price: $6 to $7
What it is: Performance oil pan
What it does: A lot more than just hold oil. There are pans specifically designed for most wet-sump performance applications, from road race to circle track to drag or street performance. The objective is to provide capacity and control under the conditions it was designed to operate in.
What it's for: For reliable performance in any of the specific applications they are designed for, a race pan can make the difference between survival and engine failure. Though some stock pans are better than others, most stock, low-capacity open-sump pans are worthless for keeping the oil from sloshing around like a frothy glass in the hands of a staggering drunk. Many stock pans lack sufficient capacity to keep from being sucked dry in performance use.
Installation: Most bolt on in place of the stocker and a matching pick-up is required. Consider available clearance to the chassis, headers, steering linkage, and-most importantly in a street application-the ground.
Price: From $100 to $500, depending on the style, performance level, and construction, with $200 being a typical average. The Milodon circle track Chevy pan (shown) features trap-door baffles and a built-in screen-type tray and runs about $290.
What it is: Oil return screen
What it does: Prevents debris from falling into the bottom end, which is particularly useful in the event of a valvetrain failure.
What it's for: The closer the engine is to being run on the edge, the better insurance it is. A simple valvetrain failure, such as a broken lash adjuster, a spit-out lash cap, or a failed rocker can turn into major destruction if the shrapnel gets caught up in the bottom end. With the screens in place and a little luck, the damage may be contained until you can pick the wreckage out of the lifter valley.
Installation: Cut the screen with snips, and glue it in place with epoxy around the edges. Make sure the bond area is dry and clear of any trace of oil.
Price: Next to nothing. Kits can be had from Moroso or Milodon, or buy a suitable mesh and bond it in.
