Cam shafts
Introduction The camshaft is an apparatus often used in piston engines to operate poppet valves. It consists of a cylindrical rod running the length of the cylinder bank with a number of oblong lobes or cams protruding from it, one for each valve. The cams force the valves open by pressing on the valve, or on some intermediate mechanism, as they rotate.
Timing The relationship between the rotation of the camshaft and the rotation of the crankshaft is of critical importance. Since the valves control the flow of air/fuel mixture intake and exhaust gases, they must be opened and closed at the appropriate time during the stroke of the piston. For this reason, the camshaft is connected to the crankshaft either directly, via a gear mechanism, or indirectly via a belt or chain called a timing belt or timing chain. In some designs the camshaft also drives the distributor and the oil and fuel pumps. Also on early fuel injection systems, cams on the camshaft would operate the fuel injectors. In a two-stroke engine that uses a camshaft, each valve is opened once for each rotation of the crankshaft; in these engines, the camshaft rotates at the same rate as the crankshaft. In a four-stroke engine, the valves are opened only half as often; thus, two full rotations of the crankshaft occur for each rotation of the camshaft. DurationDuration can often be confusing because manufacturers may select any lift point to advertise a camshaft's duration and sometimes will manipulate these numbers. The power and idle charateristics of a camshaft rated at .006" will be much different than one rated the same at .002". Whenever duration is quoted, be sure to note the lift at which it is given. Many performance engine builders have learned to gauge a race profile's aggressiveness by looking at the duration at .020", .050" and .200". The .020" number determines how responsive the motor will be and how much low end torque the motor will make. The .050" number is used to estimate where peak power will occur, and the .200" number gives them an estimate of the power potential. In general, duration determines how many crankshaft degrees a camshaft maintains more than a given tappet lift. Camshaft positionDepending on the location of the camshaft, the cams operate the valves either directly or through a linkage of pushrods and rockers. Direct operation involves a simpler mechanism and leads to fewer failures, but requires the camshaft to be positioned at the top of the cylinders. In the past when engines were not as reliable as today this was seen as too much bother, but in modern gasoline engines the overhead cam system, where the camshaft is on top of the cylinder head, is quite common. Some engines use one camshaft each for the intake and exhaust valves; such an arrangement is known as a double or dual overhead cam (DOHC), thus, a V engine may have four camshafts. MaintenanceThe rockers or cam followers sometimes incorporate a mechanism to adjust and set the valve play through manual adjustment, but most modern auto engines have hydraulic lifters, eliminating the need to adjust the valve lash at regular intervals as the valvetrain wears. Sliding friction between the surface of the cam and the cam follower which rides upon it is considerable. In order to reduce wear at this point, the cam and follower are both surface hardened, and modern lubricant motor oils contain additives specifically to reduce sliding friction. The lobes of the camshaft are usually slightly tapered, causing the cam followers or valve lifters to rotate slightly with each depression, and helping to distribute wear on the parts. The surfaces of the cam and follower are designed to "wear in" together, and therefore when either is replaced, the other should be as well to prevent excessive rapid wear. In some engines, the flat contact surfaces are replaced with rollers, which eliminate the sliding friction and wear but adds mass to the valvetrain. Importance of Cam shafts in tuningMajor BrandsBlox BLOX Racing offers enthusiasts its high performance line of Tuner and Competition Series camshafts in several different profiles, as well as, its line of semi-blank camshaft cores. All camshafts are designed and manufactured using the latest software and casting technologies, then CNC-ground to precise tolerances and performance specifications. Each camshaft profile designed offers increased horsepower and torque across the entire RPM range. Tuner Series camshafts are designed using standard, OEM lobe designs while Competition Series camshafts are designed and cast with wider primary and secondary lobes. Although both types offer increased power and torque, Competition Series camshafts place less stress on the valvetrain and provide greater stability at extreme RPM's. Consequently, all camshafts are cast using the same materials and standards as OEM sources. Semi-blank camshaft cores are also available for more serious enthusiasts and engine builders. Semi-blank camshaft cores provide a starting point for those that want to grind their own specifications and profiles. Each semi-blank camshaft core is made using the exact standards as Tuner and Competition Series camshafts. This is a great alternative when certain or specific specifications and profiles are not made available. BLOX Racing recommends upgrading to its high compression valves, heavy duty valve springs, and Ti retainers on certain applications. ProductsB Series
D Series
H Series
Mitsubishi
Semi Blanks
Skunk 2Pro series CamshaftSkunk2 Pro-Series professional line of racing cams are designed to optimize mid-range and top-end HP and TQ; and significantly reduce lap times. VTEC crossover is seamless allowing for the broadest possible powerband. No other line of racing cams can even come close to the performance of the Pro-Series line. Pro-Series patent pending camshaft profiles dramatically improve horsepower, torque, engine response, and valvetrain stability. The Pro 1 cam is the BEST ALL-AROUND STREET CAM and dramatically improves horsepower, torque, engine response, and valvetrain stability. Pro-Series camshafts feature a seamless crossover between low and high speed cam lobes with patent pending profiles defined by specific lobe shapes as well as specific characteristics of lift, velocity, and acceleration. Pro-Series cams are all designed utilizing Skunk2’s proprietary Fast Ramp Technology and Amax Technology. Use of these two technologies allows us to design aggressive camshaft profiles that maximize area under the valve lift curve without adversely affecting valvetrain stability or reliability. In fact, the use of Fast Ramp and Amax Technologies actually makes Pro-Series camshafts more stable and less prone to spring surge at high rpms. Pro-Series camshafts also feature our newly revised camshaft blanks that have increased torsional strength, improved durability characteristics, and reduced frictional effects; all of which are the reasons why Pro-Series camshafts are superior to all other cams. Pro-Series camshafts are available in Pro 1, Pro 2, and Pro 3 designs.
Skunk2 Pro-Series professional line of racing cams were designed to optimize mid-range and high-rpm HP and TQ; and provide a seamless transition from the low-speed cam lobe to the high-speed cam lobe. In order to achieve that, we made the low-speed lobes much larger, which results in more overlap and lower and less consistent vacuum at idle. When the ECU sees this lower vacuum, it tries to compensate by enriching the fuel mixture making the car idle rough. In order to make the engine idle smoothly, it is necessary to reduce the fuel by 20%-30% in the 0-1500 rpm range of the fuel map. To get the smoothest idle possible, we recommend tuning by throttle position. Please note that if the cams are not degreed in to their proper position, it may make getting the car to idle more difficult; therefore in order to optimize power output and minimize idling and clearance issues, we recommend that all Pro-Series cams be degreed in. During the '99-'05 Race season Skunk2 set several ALL MOTOR Records using Skunk2 Tuner Cams. Skunk2's new Pro Series line of cams takes performance to a new level 1999 1st Honda in the 10's 2004 "Hat Trick" 4 records set in 3 sanctioning bodies. 2005 Quickest 9.63 @ 141.80 MPH
Profile designed to maximize area under the lift curve without compromising reliability and valvetrain stability. The Skunk2 profile has more duration than competitors at lifts above 1mm resulting in greater efficiency and power.
1. The same camshaft design technology used in F1. 2. Designed to reduce seat timing and build more torque 3. Carefully designed to not damage valvetrain parts 4. Allows engine to build additional cylinder pressure
SKUNK2 CAM STAGESPro 1: High Lift Street/Race cam designed to optimize mid-range and top end HP and TQ. Peak power is designed to occur at factory redline. Pro 1 cams also perform great in high-output turbo racing engines. Valvetrain upgrade required. Pro-Series valvetrain recommended.
Pro 3: Extreme Street/Race cam designed to optimize mid-range and top end HP and TQ. Peak power is increased and power band is moved 700rpm higher than Pro 2. No other high rpm racing cam can come close to the Pro 3. Pro-Series valvetrain required Skunk2 SpecsB Series Pro DOHC Vtec specs
B Tuner Series DOHC Vtec specs
K20A2 Tuner Series DOHC Vtec specs
K20A3 DOHC Vtec specs
S2000 DOHC Vtec specs
Mitsubishi 4G63BT specs
Subaru WRX EJ20 specs
Tuner Series CamshaftDynograph
Camshaft installation and other Resources
Products
GreddyGreddy camshaft comes in two variation.
The Greddy Pro Series camshafts harness the maximum torque and power from modified cylender hear. Adjusting valve timing allows to optimize the powerband according to need. The Pro series camshafts are designed for professional tiners looking for max HP under high RPM. Additional valve train upgrades is needed. The proseries camshafts are sold seperately for intake and exhaust profiel for specific powerband. GREDDY EASY (STREET) CAMSHAFTS
GREDDY STEEL HIGH CAMSHAFTS
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