New clutch concept for modern Muscle cars, dual- and triple-disc

New clutch concept for modern Muscle cars, dual- and triple-disc

For some time, Ram Clutches had been seeking lighter pedal effort on high performance clutch systems while maintaining adequate clamping loads but couldn’t devise a diaphragm pivot arrangement within the traditional steel cover assembly to achieve it. Though their current designs perform well, in this crusade they offered little potential for improvement, prestige or reward. So, to develop their new series of clutches for contemporary Muscle cars, they set about constructing their own billet aluminum cover assembly that resolved this problem and two others. › Revised mechanical ratio brings light pedal › Direct replacements for new Corvettes, Mustangs and Hellcats › Higher diaphragm fingers prevent over-center shifting issues › Straight retaining straps improve durability   Columbia, SC: Ram is announcing new Pro Street clutch systems. They contain their best-operating geometry yet. To date they are available for six contemporary Muscle cars (listed below). For a long time the mechanical ratio in most high-performance street-vehicle clutches has remained fixed. The clamping pressure within the familiar steel clutch cover assemblies has been adapted to adequate standards but the pedal effort is not always so. In addition, the conventional straps that secure the pressure ring to the cover assembly, though capable, have been susceptible when exposed to abuse—usually from violent downshifts or by missing a gear—and the height of clutch fingers was rarely optimum. Last year Ram embarked on developing new aluminum billet cover assemblies. Their principal purpose was to gain control over the positioning of the pivot points—the diaphragm spring fulcrum—and thereby attain the elusive lighter pedal. They also improved the layout of the pressure-ring retaining straps, which now adopt a...
Under Pressure: why hot rod oiling systems fail

Under Pressure: why hot rod oiling systems fail

By Ray T. Bohacz: If a fluid is considered incompressible how does any hydraulic system create pressure? An engine’s oiling system bows to many laws of hydraulics even though the oil is not considered a working fluid. An example of a working fluid is brake fluid, which is used to perform the task of forcing brake pistons against brake discs to retard the motion of a vehicle. Pressure is created in a hydraulic system by limiting or restricting flow. The simple garden hose is the best teacher of this theory. A hose without a nozzle has a high rate of volume pass through it but with negligible pressure. When the nozzle is attached the discharge pressure increases but the rate of flow decreases. The nozzle is a restrictor that varies in orifice size. Thus, a restriction is needed to increase pressure. In a hydraulic system the pressure and flow are inversely connected. System pressure in an engine is used for a number of things: it pushes the oil through the intricate passages so all of the parts can be lubricated. It also creates an oil film between the crankshaft journal and the bearing that prevents the two parts from touching. The oil allows an engine to keep running, avoiding the catastrophe of seizure. Reading the engine oil pressure on a gauge is the cumulative effect of the bearing clearances (both rod and main), the viscosity (thickness of the oil), the length, diameter and surface finish of the oil passages referred to as galleries, along with the output of the pump and the speed of the engine. Most engines employ...
Deck wave: What is it and how is it checked?

Deck wave: What is it and how is it checked?

By Titus Bloom: Research of racing parts invariably includes discussions with race engine builders and manufacturers. During their course, jewels of information can emerge, as was the case when we were developing a story following JE’s announcement of their advanced Pro Series head gaskets. Sometimes the gems are universally known sometimes not – still, these recent comments on surface flatness by Dick Boyer, designer of the latest engine blocks from World Products, seem noteworthy. “The profilometer is useful,” says Boyer, “but measuring the scratch depth in a deck surface is usually of less consequence than wave finish. What would be the point of having a beautifully smooth surface with a potentially threatening wave depth of 0.002in or 0.003in? Some builders probably put too much emphasis on profilometer readings and maybe not enough on surface flatness.” How do you check wave finish? “We lay a granite plate with 300-grit sandpaper on the deck of the block and stroke it five times front to rear—you’ll see the high spots, you’ll see the wave, which we measure with an indicator. We aim to limit variations in wave depth to 0.001in. It’s easy to control the prolifometer readings; it’s less easy to control the wave. I’ve seen waves measuring 0.002in which introduce sealing problems.” Boyer on torque-to-yield fasteners “When installed, torque-to-yield fasteners, which are common on road-going vehicles, are stretched to their maximum limit and discarded after use. If the bolts are not stretched to their full extent when the engine reaches normal operating temperature, they stretch a little more and the gasket gets loose. Torque-to-yield fasteners are not common in racing engines.”...
Servicing Mass Airflow Sensors

Servicing Mass Airflow Sensors

Ray Bohacz is a journalist in the automotive field and author of CarTech’s book “How to tune and win with Demon Carburetion”. He is also a monthly contributor to Hemming’s Muscle Machines magazine. Additionally, Ray writes short articles for the agriculture industry and is featured in a series of videos as the SF (Successful Farming) Engine Man. His videos introduce brief, informative features which apply to both farm and automotive equipment. Most modern fuel injection systems employ a mass air flow sensor (MAF) that is located between the air filter assembly and the throttle-body. The MAF measures the air flow into the engine. This data is mainly used by the engine controller (ECU) to determine fuel injector pulse width. The MAF output is also combined in an algorithm with the outputs from the crankshaft and throttle position sensors to determine engine load. This influences both fuel and ignition timing. The MAF output will skew when coated with air-borne contaminants. This is how to easily restore its accuracy. Watch the...
Helpful tips you need to know about racing oils

Helpful tips you need to know about racing oils

Meet specialist Len Groom. By Freddie Heaney: Between a crankshaft journal and a rod bearing a film of oil resides in a space approximately the thickness of a human hair. In last year’s Pro Stock 500cu in V8 racing engines, crankshafts were spinning near 11,500rpm. In 2006 the V8 Cosworth F1 racing engine reached an astonishing 20,000rpm. Oil film operating in passages the thickness of a piece of paper prevented their parts from touching—as it is in most racing engines. Oil film, which is also referred to as an oil wedge, can be better understood if you consider a piston ring moving down a cylinder. When in motion, the oil begins to accumulate before the ring and forms a wedge-like shape. If severe, the ring can hop on top of the oil wedge, which breaches the seal between the ring and cylinder wall, causing blow-by of combustion gases. Though more difficult to visualize, the wedge effect is also present in the lubrication space between the crankshaft journal and the rod bearing. Its depth measures approximately 0.003in. Recently, at the annual MPMC conference where 100 racing parts manufacturers met the media, AMSOIL’s Len Groom was on hand, as intelligent a man as ever discussed synthetic racing oils. High quality racing oils, he explains, demand attention in several key areas in order to provide protection. Two of the most important areas lie within their film strength and resistance to viscosity loss under high pressure. “In fact,” says Groom, “when racers using our 15w-50 tell me they are running oil temperatures of 260F, I don’t get too concerned so long as the...
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