Camshaft lobe separation angle: what does it mean?

Camshaft lobe separation angle: what does it mean?

By Freddie Heaney: The lobe separation angle of a camshaft is typically determined by the engine’s purpose, its displacement and its compression ratio. A 350cu in oval track racing engine, for example, often runs on a narrow lobe separation angle of 106 degrees. In contrast, a smooth-running high-performance street engine might use a lobe separation angle of 112 to 114 degrees. Five-hundred cubic inch NHRA Pro Stock engines that rev to 11,000rpm operate on 116 degrees and 800-plus cu in Pro Stock Mountain Motors 120 to 122. The lobe separation angle or LSA is the angle in camshaft degrees between the maximum lift points, or centerlines, of the intake and exhaust lobes. It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open. A narrower LSA adopts more overlap and with it a lumpier idle and a narrower more specific power band. The narrower separation makes the engine sound choppier. Some engine specialists refer to it as that 106 sound—the NASCAR and short track oval sound where preferred lobe separation is usually specified between 104 and 106 degrees. The primary function of narrow lobe separation is to impel urgent acceleration off the turns when the throttle is opened. A wider LSA, on the other hand, reduces valve overlap, offering better idle and cruising qualities. Supercharged engines typically benefit from a wider LSA because they don’t require as much overlap for exhaust scavenging as does the naturally aspirated engine. “Changing the lobe separation angle,” says Doug Patton of Pro Line Race Engines, “changes the amount of overlap that...
What can we learn from an intelligent belt-drive assembly?

What can we learn from an intelligent belt-drive assembly?

Salina, Kansas: Innovators West has introduced two new belt-drive systems for Ford Windsor 302 or 351 engines. They serve wet- or dry-sump arrangements. One style is equipped with integral side brackets for serious track use, the other without. The side brackets are regarded as unique. They accommodate the mounting of an external oil pump or a vacuum pump or a belt-driven fuel pump, often a requirement for turbo or blower engines. Hole-center spacing is similar to that of the big-block Chevrolet. On drag race cars, external competition pumps are customarily mounted on the 1/4in thick aluminum engine mounting plate, but this is rarely satisfactory as the plate is apt to deflect, resulting in imperfect belt alignment. Besides generating less friction, the essential proposition of a belt-drive system is its ability to maintain precise valve timing, particularly at high engine speeds. It also has the capacity to eliminate harmful harmonics. Acting as a damper, it absorbs vibration and noise transferred from the crankshaft to the valve train, thus guarding against valve train instability. As expected, Innovators West has machined slots in the cam pulley to degree the cam. This simply means that valve timing events can be advanced or retarded, which is convenient during dyno tuning. Significantly, an eccentric idler pulley is supplied to overcome difficulties of tensioning the belt when using different diameter pulleys and compensating for belt stretch over time. The cam pulley, incidentally, is of hard-anodized billet aluminum while the crank pulley is made from heat-treated steel. Both pulleys are machined in a multi-axis lathe in one operation to ensure exact concentricity. In addition, a cam retaining...

Garlits to remarry and other anecdotes

By Martha Maglone:  Last month, February 2015, Don Garlits (83) popped the question to photographer Lisa Crigar, whom he met during a magazine interview in 2014. They plan to marry 25 July 2015 at the Don Garlits Museum of Drag Racing in Ocala, Florida. Don Glenn Garlits’s mother had ambitions for her son; she wanted him to train as an accountant, and though he tried the profession it had no appeal. Inspired only by thoughts of racing, he went to work in an auto body-shop and later founded Don’s Speed Shop. It is likely Garlits would have succeeded in any form of racing, but he fell under the spell of drag racing while growing up in Tampa. “In those days we all had hot-rods – cut-down Coupes were the top of the line. I had a 1940 Ford with a Cadillac engine, and we went racing on an abandoned army base in Zephyrhills,” he recollects. “We marked out a quarter mile, went flat out all day long, no clocks, just a guy who flagged us. That was June 1950.” Occasionally, his pal AJ Foyt reminds him that in oval track or road racing if you’re a tenth off here or there you have the opportunity to recover and still win. In drag racing, if you’re a hundredth or even a thousandth off, your race is likely finished. What makes the difference? “Reflexes and focus are the two main elements—you’ve got to have those because there’s no second chance,” says Garlits. “Before a run I’d sit in the truck and take a power nap and come out fresh and sharp....
New sprint car crate engine program using factory-sealed Chevrolet 602 and 604

New sprint car crate engine program using factory-sealed Chevrolet 602 and 604

By Bertie Scott Brown –  Boardman, Ohio: When Pace Performance discovered sprint cars in the northeast spent more time languishing in garages because owners couldn’t afford to race them, they decided to try a different approach. Last year, 2014, they prepared a Chevrolet Performance factory-sealed 602 and tested it over a full season of racing against traditional 305-powered machines. It proved competitive, finishing regularly in the top five, durable, and overcame the cost obstacles. This year they are launching their new crate engine program offering the 602 and 604. The 602 generates 400hp @ 5,600rpm and 440lbs ft of torque @ 3,800rpm and costs $3,975. The 604, on the other hand, is equipped with fast-burn aluminum cylinder heads and a more aggressive camshaft. Both engines are provided with a Crate Innovations crank balance hub and slip yoke assembly.       The process GM delivers the crate engines to Pace Performance with factory-sealed fasteners. Pace adds a cam spud to the rear of the camshaft which drives the fuel pump and power steering pump if required. Then their partner Race1, headed by Brad Hibbard, installs secondary cable seals on the existing engine fasteners and applies tamper-proof tape over the seals with a QR code. Should a tech inspector wish to scan it with a Smart phone, a page will appear that identifies every seal and its location as well as every serial number. Like to see a 602 sprint car in action? Click here. Eligibility of the 602 and 604 depends upon individual track owners and race series promoters, but the response so far, according to Pace Performance, has...
New 454cu in engine block: World Products launches formidable Windsor-style competitor

New 454cu in engine block: World Products launches formidable Windsor-style competitor

By Alfie Bilk:  Introducing a new engine block with big power potential, understandably, gives rise to a sense of occasion. First, consider the time and treasure invested in its creation. Also, consider the enormity of the engineering details and the designer who tirelessly examined hundreds of complex regions of the new casting. It’s an endeavor not for the faint of heart. But its culmination is exactly what we observed at the end of 2014 when, during the PRI exhibition in Indianapolis, World Products unveiled two innovative Ford-based blocks. Both defined as small-blocks they are distinguished mainly by their deck heights: one measures 8.2in., the other 9.5in. The 9.5 version displayed in finished form sported a displacement of 454cu in (7.4L), exhibited a host of advantages, and echoed the biggest engine news of the show. It is called Man O’ War. The Man O’ War block had existed previously, but when World Products was sold in late 2012 the new owners decided to entirely revise it. Now graced by new architecture and the brainchild of World’s Engineering Director, Dick Boyer, it accommodates the original 10-bolt cylinder heads as well as the latest aftermarket high-performance 18-bolt counterparts. Introducing six head bolts per cylinder combined with extra thick decks greatly reinforces gasket clamping. But its sporting credentials didn’t end there. Devoted to the idea that the new engine should be the strongest and most rugged, Boyer, an accomplished race engine builder and tuner, cast the new power unit in a 40,000psi iron alloy. He also increased the thickness of the main bearing webs, upgrading the front one by adding 0.080in and the...
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