John F. Katz 2013-03-25 12:19:52
Groundbreaking innovations are flowing through the engineering pipeline with more design solutions to keep race engines performing at their peak. Oil pump manufacturers report today’s racers and engine builders expect nothing short of miracles from their oil pumps. “It’s very simple,” said one. “They expect an oil pump that delivers another 100 to 120 horsepower.” More realistically, however, racers and engine builders expect an oil pump that will keep their engine alive, for a minimal cost in horsepower. “Today’s customers expect oil pumps to deliver consistent volume and good pressure at high operating temperatures,” said Steve Faria of System 1 Filtration, Tulare, California, “without cavitation and without robbing a lot of power.” And while racers know—well, some know—that price is usually indicative of quality, they’re still looking for a bargain. “They do expect a quality product at a decent price,” added Stefan Verdi of Auto Verdi, Costa Mesa, California. “Particularly in the last five to six years, since the recession, more and more customers have become sensitive about pricing.” Sensitive, yes, but not unrealistic. As Bob Sanders of Titan Speed Engineering, Ojai, California, told us, “Most racers know that sometimes the best money spent on an engine is in the oiling system.” We’ll examine the whole oiling system at another time. Here we’re going to concentrate on oil pumps—not only what’s new and what’s better, but why. Tight Clearance Roy Johnson of Johnson’s High Tech Performance, Valencia, California, started out by explaining why oil pumps are responsible for more engine failures than many racers or even engine builders realize. “They find engine debris in the oil pump, so they think the engine failed and ruined the pump—when in fact the pump failed and ruined the engine, and that caused the pump to ingest engine parts.” So how do you choose a pump that won’t fail? According to Johnson, you first have to understand some of the engineering involved. He repeatedly emphasized that “it’s imperative to hold very close clearances in any pump. Clearance relates to efficiency: the tighter the clearance, the more efficient the pump.” And a more efficient pump delivers more oil with less vapor. Engines don’t require a particular oil pressure, Johnson continued. What they require is sufficient “volume of oil, specific to the viscosity, to obtain the needed heat exchange, because the oil system represents 80 percent of a race engine’s cooling.” Once the main gallery is filled, it’s not pressure but hydrodynamic siphoning that draws oil to the bearings. “So let’s take a pump that’s 60–70 percent efficient; that means you have 30–40 percent vapor in your main gallery. Well now when you accelerate the engine, you are going to use up the 60–70 percent oil that’s in there very quickly, and then you are going to hit a vapor bubble. And that’s when you lose a bearing. “The blistering and pitting you see in a bearing is created by cavitation from vapor infused into the oil,” added Johnson. As the oil flattens out in the bearing, the vapor is violently forced out, briefly reaching 2000 degrees F or more—with a correspondingly destructive effect on the bearing. The needles in roller lifters are even more vulnerable to this sudden release of heat energy than are the plain bearings in crankshafts and rods. Engine builders deduce—correctly—that a bearing failed because it didn’t get enough oil. But unless they consider the efficiency of the oil pump, they are likely to conclude that the answer is more oil pressure. “So now because of the large clearances and low efficiencies of many oil pumps,” said Johnson, “engine builders have forced themselves into a rule of 10 psi per 1000 rpm. They know as long as they follow that rule, they don’t seem to have engine failures. “But adding pressure to the oil drives more heat into the oil, while consuming horsepower, because the more pressure there is on the system the more energy is required just to turn the pump,” he continued. “So to reduce resistance to flow, many racers and engine builders are now turning to low-viscosity oil. But then they flow it too fast through the engine for proper cooling.” And in reality, oil pressure is a poor indicator of oil volume. “High oil pressure just means the gallery is packed. It doesn’t tell you what it’s packed with,” said Johnson. It could be mostly vapor. “Well, if you have 45 psi constant pressure, and you are still failing bearings, it’s because there is too little oil and too much vapor in the gallery.” Make It Modular According to John Schwarz of Aviaid Competition Oil Systems, Chatsworth, California, one of the primary issues faced today by both oil pump manufacturers and engine builders is how to physically attach the pump to increasingly complex engines stuffed into increasingly small spaces. Once the pump is mounted, however, his concerns echo Johnson’s: “The next thing to consider is how to deliver enough oil to the engine. And to that end we now have pressure sections with 10 different displacements that can be assembled into pumps from two to three gpm up to 40-plus gpm. With that range we cover motors from 600cc up to 1000 cid with turbochargers or superchargers. We also have the capacity within our systems to deliver from 40 psi up to pressures approaching 300 psi. Aviaid’s scavenge sections cover an equally impressive range, from .600 inch in width to 2 inches, “and in three different types. Our standard gear set is the same spur gear set we use for our pressure sections. Then we have an enhanced spur gear set that provides a 25–35 percent increase in displacement,” said Schwarz. Simply speaking, the enhanced gears have fewer teeth, leaving more room for oil. “That wouldn’t necessarily work on the pressure side, because the fewer teeth you have, the greater the pulsation in the system. But on the scavenge side pulsation is not such a problem, and the increased displacement allows us to run up to 25 inches of vacuum. “Our third type uses a standard two-lobe Roots rotor, which provides 15 percent more displacement than the high-displacement gear pump”—that’s up to 55 percent more than the standard set. “Our goal is to provide the engine builder with the flexibility to fine-tune the heart of the lubrication system using all off-the-shelf parts,” concluded Schwarz. Certainly, the different rotor configurations all have their supporters— and detractors. The best-selling oil pumps from ARE Dry Sump Systems of Loomis, California, “are our new LS1–6 direct-to-block-mounted pumps,” said Gary Armstrong, “which combine the long life and efficiency advantages of a gear-type pressure section and a Roots scavenge section routed to the area in our dry sump pans where the most air is present. Another feature of our pumps are built in screens at the fittings to keep out the inevitable debris—a simple feature that can add many hours of life to the pump at a very small cost.” Also popular from ARE are four to five stage side-mount pumps “which fit nicely on inline engines’ dry sumps; and our Mini pump, which delivers oil efficiently and without cavitation at pump speeds beyond 10,000 rpm.” RaZor Performance Oil Pumps in Mesa, Arizona, “pioneered the aluminum seven-tooth gear/impeller,” said Terry Palmer. “The seven-tooth configuration is a hybrid of a gear and an impeller,” which RaZor judges to be the ideal solution. “We have experimented with other designs, but have not found any that provide a significant edge in flow or reliability.” RaZor’s top seller is a three-stage unit designed for the Chevrolet small block, although the company clearly prides itself on its ability to provide custom oil pumps for any application. “All System 1 billet oil pumps are of the spur gear type,” said Faria. “They run on roller bearings, which reduce drag and require less power to turn. And with a spur gear pump the oil pressure remains linear throughout the engine’s rpm range—whereas most gerotor pumps max out around 6500 rpm.” This is especially true in nitro-powered drag racers where “the motors need as much cushion of oil on the crankshaft as possible.” In addition to pro Funny Car teams, now alcohol Funny Car and Pro Mod teams are realizing the benefits of its dry-sump pumps as well. And the same principle, Faria added, applies to System 1 wet sump pumps for Top Fuel and Top Alcohol dragsters. “The more positive spur-gear design is better suited for high-rpm scavenge-in and pressure-out applications. In short, the better the suction, the better the pump.” At the 2011 PRI Trade Show, Moroso Performance Products of Guilford, Connecticut, debuted its Tri-Lobe line of dry-sump oil pumps. “They have spur-gear pressure sections based on our highly successful billet wet sump design,” said Thor Schroeder, “but the scavenge sections use three-lobe rotors with individual timing gears, to ensure proper clearance even at the highest rpm’s.” Compared to a geroter pump, Moroso’s Tri-Lobe pump weighs about half as much and requires only 40 percent of the power to drive it. Other features include “variable spring rates to optimize oil pressure for smooth, reliable oil pressure readings; multiple #16 scavenge outlet options for increased flow back to the dry sump tank and/ or other fitments; and custom pressure section sizes for increased efficiency at a range of pump speeds. A reversible door car bracket or reversible dragster bracket can be used on the driver’s or passenger’s side of the engine to accommodate different engine and/or chassis configurations.” Moroso continues to offer its line of aluminum billet wet sump pumps. “Our housings are machined from 6061-T6 billet aluminum,” Schroeder added, “which is as strong per pound as a casting, without the typical problems cast pumps have with porosity. Our mounting boss is three times larger than on traditional pumps, and the inlet area is increased to prevent cavitation. Yet our pump weighs one pound less than a traditional pump.” Titan, said Sanders, has “just recently made a new ‘shorty’ dry sump pump for Pro Mods and for nitro and alcohol Funny Cars;” while sales of Titan’s conventional line remains strong, particularly in oval track. Titan manufactures gerotor oil pumps for wet- and dry-sump applications. “Spur gear pumps have to work seven times harder to deliver the same volume of oil,” Sanders explained. “Our dual-feed gerotor design delivers a consistent flow of oil all the way to 12,000 rpm and beyond.” Furthermore, all Titan Speed oil pumps “are made in the USA, and each one is hand-built for the team that is going to use it.” Canton Racing Products of North Branford, Connecticut, offers “pressure balanced” oil pumps, said Michael Zeranski Jr., “with feeder grooves machined into the pump housing to bleed some of the high pressure back into the pump.” The result is “more constant pressure, without the pressure surges and oil cavitation that can otherwise occur at high rpm.” Canton offers these wetsump pumps “for popular Chevrolet small block and big block applications, with multiple options regarding volume and pressure.” TM Performance, Padulle di Sala Bolognese, Italy, manufactures oil pumps for motorsports applications. Federico Barbieri said, “We have a type of three-stage oil pump that is suitable for 99% of applications. For the other 1% we could develop each change to fit everywhere.” Barbieri said TM Performance has plenty of experience with racing applications, and understands that racers and engine builders demand performance, quality and availability of the product. He said the company’s oil pumps are priced affordably and offer quality that delivers performance. Material Matters Regardless of configuration, high-quality materials are essential—but, at least according to Johnson, not by themselves sufficient. “You have to look at the way you machine the material to make it more stable,” he said. “The more heat you put into the material during machining, the more it distorts.” Additionally, “hard anodizing establishes a wear barrier. We impregnate our gears with molybdenum disulfide, a dry-film lubricant that saturates and retains oil, to make them self lubricating. So now we can close our clearances down—we put zero side clearance into our pumps, because we don’t need fluid to lubricate the gears. And, of course, the final seal in any pump is created by the fluid. If you can retain fluid on the gears, you have a positive seal all the time.” Johnson offers a lifetime warranty on his Stealth oil pump. “We have customers who have run the same pump for 15 seasons,” he added. “Material is important if you expect the pump to last a long time,” added Verdi, “although everything is relative to price. We use a lot of coatings to extend the life of our pumps. Our pressure relief valve has an anti-friction coating similar to DLC; and we used Teflon not only on the rotors but on both the inside and the outside of the housing—again, for longer resistance to wear.” Bill Dailey of Dailey Engineering, Temecula, California, emphasized “the use of the same material for the housing and internal components to ensure that internal clearances will remain constant over the entire operating temperature range. We have always manufactured Roots-type dry sump oil pumps using aircraft grade aluminum for both the housings and the rotors. And we control friction by replacing steel ball or needle bearings with Teflon. It’s this attention to engineering detail that our customers— including Penske Racing—look for when they choose an oil pump.” Challenges for New & Old Verdi reported still-growing demand for the line of smaller-size dry-sump pumps Auto Verdi introduced in 2010. “It’s about half an inch smaller all around, and each stage is a quarter-inch shorter,” he noted. And particularly on a multi-stage pump, those small reductions “add up where space is an issue. More people are looking for a smaller, lighter pump to fit into tighter chassis configurations, and to reduce weight. They have to run it faster, so it’s not as efficient as a big pump turning slower. But the packaging and the weight are very critical today.” Additionally, Auto Verdi can service any of its past or present pumps. “Every housing we ever made has a number milled into it,” said Verdi, “and we have records of every product that leaves here. So the customer can easily obtain the correct parts for any pump we have ever manufactured.” Another common—and challenging characteristic of late-model engines is a stock oil pump driven off the nose of the crankshaft. “This has created an opportunity for the performance aftermarket,” observed Mike Osterhaus of Melling Engine Parts, Jackson, Michigan, “as many of these stock pumps will not meet the demands of a performance engine. Crankshaft-driven pumps have large surface areas that need to be sealed,” limiting the pressure they can deliver without leakage. “Melling’s line of Select Performance oil pumps eliminate those issues, while increasing performance and reliability at an affordable price.” Older-model OE pumps also have limitations. “Traditional cast-iron oil pumps for the small block Chevrolet V8 start to cavitate around 6000 rpm,” Osterhaus continued. At this point efficiency drops off rapidly, and neither pressure nor flow volume will increase with further increases in engine speed. “Another issue with Chevrolet engines is intermediate driveshaft failure,” he said, referring to the keyed shaft that links the distributor shaft to the oil pump assembly. “But the intermediate shaft must also allow for misalignment between the distributor and the oil pump. We have found aftermarket shafts that will not allow for misalignment. This can result in premature wear on the pump drive or even pump failure.” So when installing an oil pump, “be sure to check that the slot on the distributor end of the shaft and the tang on the oil pump side of the shaft are 90 degrees apart. Clocking the ends 90 degrees allows the intermediate shaft to move relative to the distributor and oil pump. Melling intermediate shafts are inspected to assure proper alignment of the drive slot and tang features. “Another issue we are becoming aware of relates to intermediate shaft failures in race classes that require rev limiters,” he added. “When the engine reaches the rpm limit, the result is a cyclical loading and unloading of the oil pump drive. So for these applications we recommend using our chromoly intermediate shaft. Of course, chromoly shafts are supplied with our performance oil pumps to withstand the increased loads caused by higher viscosity racing oils.” Dailey, of Dailey Engineering, expressed concerns about fitting a performance oil pump to a particular engine or chassis. More engine and chassis builders, he said, are “implementing the oil pump as an integrated component of the complete chassis assembly. While we’ve been doing this for years with our Signature Series dry-sump pans with integrated oil pumps, lately we’ve been working directly with chassis designers” to make sure the oil system will fit even before the car is built. Our Signature Series billet dry sump oil systems mount the pump directly on the pan, creating a lighter and cleaner package compared to a typical fabricated oil system plumbed with AN lines.” Dailey specializes in custom-made dry sump oil pumps and systems. “Every day we’re working with customers to create new pumps to fit their needs,” Dailey stressed. “We have 947 unique pump configurations to date, and we create new designs all the time.” Frank Honsowetz of Ed Pink Racing Engines, Van Nuys, California, noted demand for small runs of oil pumps with custom-engineered housings “where the outside of the housing is adapted to specific features such as mounts, fittings, sensors, etc.” One series was produced for Nissan’s racing program in Japan, where “they provided us with solid models and drawings for external features to fit their specific application.” Lubricating Add-ons “The oil pump is just the heart of the operation,” said Sanders. “The whole oiling system must work well together, including pans, sumps, oil control, oil drain back, etc.” “You need to do more than just sell the highest quality pump,” Johnson agreed, “you have to address the system around the pump. To keep suction hoses from collapsing, you need either a hard line or, if the customer wants a flexible hose, make sure it has an internal support coil. Make sure they have a high-flow, low-resistance filter on the return side, and make sure their reservoir has a baffle-breather canister to release all the vapor out of the oil.” “Good quality plumbing is important,” Verdi confirmed, “as well as tanks and pans. All should be sold together with the pump.” “All engine builds require a new oil pickup tube assembly,” added Osterhaus. “For many GM applications, this is especially critical, since the tube is pressed into the oil pump and cannot be re-used. We have videos on our website that show how to properly install the tube into the pump and check for proper clearance to the oil pan.” “The driveshaft, mounting stud, and oil pickup are the items that most directly relate to the oil pump,” said Zeranski. Canton sells “upgraded high-grade-steel driveshafts with pinned steel sleeves for SBC and BBC applications—and we recommend them with any high-performance engine build. We also recommend our SBC and BBC mounting stud for the oil pump, which can be permanently secured in the main cap for easy installation and removal of the pump. The oil pickup will be determined by the pan; most of our oil pans have pickup tubes specific to each pan-and-pump combination.” Palmer advised, “The biggest favor you can do for your customers is to sell them a screen for the scavenge lines, to catch large engine debris before it wreaks havoc in the pump.” And Dailey offers “a complete line of HTD-style oil pump pulleys. This pulley design uses a taper collet clamping that does not harm the shaft, and is very easily moved or removed. We also provide a pulley-and-belt center calculation program to help end users choose the right parts for their installation.” Schroeder reminded us that Moroso offers a line of wet sump oil pans with the oil pump and pickup already welded in; or customers may choose to purchase the separate components and assemble them themselves. “We also offer a variety of louvered and screened windage trays, crankshaft scrapers, dry sump tanks, breather tanks, fittings, filters, pump drive kits, pre heaters, and six styles and/or sizes of accumulators. Another point to consider is that when you are selling components for an engine build, an oil pump and pan should be part of the equation.” Mark Mittel, of System 1, added, “It’s very important that the customer gets the right parts and equipment the first time. They need the correct filters, hoses, fittings, mounts and accessories. Even the weight of the oil is a major concern in some applications. You wouldn’t want to send a customer out the door with a family-car oil filter and 70-weight Nitro Blend oil.” Schwarz worries that critical knowledge and skills are disappearing as a generation of engine builders retires, “and the younger ones don’t necessarily understand why they are doing what they do. Just to choose the correct sizes for oil lines and the best locations for components requires a broad body of knowledge. And we, the manufacturers, have become by default that body of knowledge. So if you have questions, go to somebody who knows what they are doing and ask for help.”
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