Retrofitting performance camshafts to an internal combustion engines with hemispherical combustion chambers

A method for installing a camshaft retrofitting kit into an internal combustion engine with a plurality of hemispherical combustion chambers in order to provide increased power. A variable camshaft timing (VCT) assembly and a plurality of displacement-on-demand (DOD) control solenoids are replaced with a VCT plug and a plurality of DOD plugs respectively. A performance camshaft is installed in place of a stock camshaft, and a performance camshaft drive assembly is installed in place of a stock camshaft drive assembly. A cam adapter may also be provided in order to extend the length and diameter of the performance camshaft. Additionally, a plurality of springs from a plurality of cam followers is replaced with a plurality of spacers.

FIELD OF THE INVENTION

The present invention relates generally to a system for increasing the power of an internal combustion engine. More specifically, to a method for retrofitting performance camshafts to internal combustion engines having a plurality of hemispherical combustion chambers.

BACKGROUND OF THE INVENTION

The first Chrysler “Hemi” V8 engines appeared on the market in 1951. Since that time, said “Hemi” engines have been used extensively in the custom car field, being modified and swapped into countless custom vehicles, and in racing form, achieving dominance in several forms of motor racing.

The contemporary implementation of the Chrysler “Hemi” V8 engine first appeared on the market in 2003, in the 5.7 liter version. Since that time, Chrysler Corp.

has produced other versions, including 6.1 liter and 6.4 liter engines. The fuel delivery and spark delivery systems on the contemporary versions of the “Hemi”, like all contemporary automotive engines, are controlled by a dedicated purpose computer, known as an Engine Control Unit, or ECU.

During the 2009 production run, Chrysler Corporation improved their 5.7 Liter Hemi Engines with regard to better fuel economy and reduced emissions performance by the installation of a Variable Camshaft Timing (VCT) system and a Displacement-on-Demand (DOD) system in those engines. Under the control of an upgraded ECU, the VCT system changes the angular position of the camshaft with respect to the crankshaft as a function of the power being requested from the engine (driver's gas pedal position) and engine revolutions per minute (RPM). With VCT, the engine system can provide lower emissions and greater economy in response to real time conditions.

The DOD system deactivates half of the engine's cylinders (alternate cylinders in the firing order) under conditions of low power demand, which reduces engine pumping losses under conditions of high manifold vacuum, thereby providing significant increases in fuel economy and reductions in emissions-per-mile.

There is an expanding demand for late model Chrysler Hemi engines in the custom car, aftermarket and high-performance automobile construction fields. In many of those projects, the customer wants the engine to be modified to produce significantly greater power than does the stock engine.

One of the essential modifications along the path to greater engine power is the replacement of the conservative factory camshaft with a “performance” camshaft that opens and closes the valves faster than the stock camshaft, opens and closes the valves at different points in the operating cycle than does the stock camshaft, and lifts the valves higher than does the stock camshaft.

Unfortunately, the VCT and DOD systems preclude the replacement of the stock factory camshaft with a performance camshaft. There are two reasons for that limitation.

First, the effective range of camshaft position adjustment which the VCT system provides would guarantee that, as a result of the higher valve lift values that performance camshafts attain, all the valves would collide with the pistons at the extremes of VCT adjustment travel. That would cause immediate, severe engine damage and probable engine destruction.

Secondly, performance camshafts impose acceleration rates on the cam followers that are substantially greater that those embodied in the stock camshaft. That causes much higher axial forces to be imposed on the DOD-style cam followers at high engine speeds, and those higher forces overpower the DOD cam followers' ability to remain in the non-collapsed (active) position, causing the DOD cylinders to unintentionally deactivate at high power-high rpm operation.

It is therefore an object of the present invention to provide the ability to install a performance camshaft in the new VCT-style Hemi engines by means of replacing the VCT and DOD components with suitable alternatives.

DETAIL DESCRIPTIONS OF THE INVENTION

The present invention is a camshaft retrofitting kit that improves the standard power of an internal combustion engine with a plurality of hemispherical combustion chambers. The internal combustion engine with a plurality of hemispherical combustion chambers is different from other combustion engines, mainly due to hemispherical shaped combustion chambers, where the hemispherical shaped combustion chambers provide lower heat escape and higher peak pressure. The internal combustion engine with a plurality of hemispherical combustion chambers is hereinafter referred to as the hemispherical internal combustion engine. The present invention provides a low cost and efficient method for retrofitting performance engine parts, wherein the method can be carried out by an individual who has a basic knowledge of internal combustion engines.

In reference toFIG. 1, the camshaft retrofitting kit comprises a plurality of displacement-on-demand (DOD) plugs10, a variable camshaft timing (VCT) plug11, a performance camshaft12, a performance camshaft drive assembly13, a plurality of spacers15, a plurality of new gaskets14, and an instruction manual17. The performance camshaft drive assembly13comprises a performance timing chain131, a performance timing chain guide132, a performance timing chain tensioner133, a performance crankshaft sprocket134, and a performance camshaft sprocket135.

In reference toFIG. 2, the hemispherical internal combustion engine comprises an engine block, an oil pan, an intake manifold assembly, a pair of rocker covers, a pair of cylinder heads, a plurality of pushrods, a timing cover, an oil pump, a stock camshaft drive assembly23, a camshaft locating plate, a stock camshaft22, a crankshaft, a VCT control assembly21, a plurality of DOD control solenoids20, and a plurality of cam followers30. The stock camshaft drive assembly23comprises a stock timing chain231, a stock timing chain guide232, a stock timing chain tensioner233, a stock crankshaft sprocket234, a stock camshaft sprocket235, and a plurality of old gaskets24. The engine block comprises a valley, which is obstructed by the intake manifold assembly. The instruction manual17provides detailed, step by step instructions for the method for retrofitting performance engine parts, such that the individual can properly install the other components of the camshaft retrofitting kit to the hemispherical internal combustion engine.

In a vehicle containing the hemispherical internal combustion engine, a number of components hinder access to the hemispherical internal combustion engine, namely an air conditioning assembly, an alternator, a power steering assembly, and a water pump of the vehicle. As such, the air conditioning assembly, the alternator, the power steering assembly, and the water pump are removed from the vehicle using standard disassembling techniques and practices known in the automotive industry in order to gain access to the hemispherical internal combustion engine. The oil pan is then unbolted from the engine block in order to remove the oil pan from the engine block and gain access to the oil pump and the timing cover. If the oil pan does not readily detach from the engine block, then a sharpened putty knife or screwdriver may be used to separate the oil pan from the engine block.

In order to gain access to the valley of the engine block, the intake manifold assembly is unbolted from the engine block. The intake manifold assembly is then removed from the engine block and set aside. Once the intake manifold assembly has been removed, the pair of rocker covers and the pair of cylinder heads can then be detached from the engine block as well in order to gain access to the plurality of push rods and in turn the plurality of cam followers30. Each of the pair of rocker covers is unbolted from the pair of cylinder heads and then removed and set aside. Similarly, each of the pair of cylinder heads is unbolted from the engine block and then removed and set aside.

In reference toFIG. 3andFIG. 9, once the oil pan, the intake manifold assembly, the pair of rocker covers, and the pair of cylinder heads have been removed, the hemispherical internal combustion engine can be further dismantled. Namely, the oil pump, the timing cover, the stock camshaft drive assembly23, the camshaft locating plate, the stock camshaft22, the VCT control assembly21, the plurality of DOD control solenoids20, the plurality of pushrods, and the plurality of cam followers30are removed in succession from the engine block of the hemispherical internal combustion engine.

In reference toFIG. 9andFIG. 12, the timing cover, the camshaft locating plate, the stock camshaft22, the VCT control assembly21, the plurality of DOD control solenoids20, the plurality of pushrods, and the plurality of cam followers30are removed from the engine block using standard techniques and practices known in the automotive industry. Similarly, the stock timing chain guide232, the stock timing chain tensioner233, the stock timing chain231, the stock crankshaft sprocket234, and the stock camshaft sprocket235of the stock camshaft drive assembly23are removed from the engine block using standard techniques and practices known in the automotive industry.

In reference toFIG. 2, the plurality of DOD control solenoids20resides in the valley of the engine block and acts to deactivate the plurality of pushrods for selected cylinders of the hemispherical internal combustion engine. The plurality of DOD control solenoids20is positioned into a plurality of bosses, wherein the plurality of bosses is in fluid communication with the plurality of cam followers30. When installed, the plurality of DOD control solenoids20provides a pressurized oil signal to the plurality of cam followers30, allowing the plurality of cam followers30to control the intake valve operation in order to activate and deactivate the selected cylinders of the hemispherical internal combustion engine.

In reference toFIG. 3andFIG. 9, once the plurality of DOD control solenoids20is removed from the plurality of bosses, the plurality of DOD plugs10is installed in place of the plurality of DOD control solenoids20. The plurality of DOD plugs10is positioned into the plurality of bosses in order to prevent the flow of oil to the plurality of cam followers30. In this way, the hydraulic actuation function of the plurality of cam followers30is disabled, and thus the selected cylinders of the hemispherical internal combustion engine are always activated.

In reference toFIG. 2, the VCT control assembly21comprises a VCT control valve and a VCT control solenoid. The VCT control valve is positioned into a cavity of the engine block, while the VCT control solenoid is connected to and positioned above the VCT control valve. The cavity is in fluid communication with the stock camshaft22. When installed, the VCT control solenoid is electronically controlled in order to actuate the VCT control valve. The VCT control valve acts to regulate the flow of high pressurized oil to the stock camshaft22in order to adjust timing of the stock camshaft22.

In reference toFIG. 3-4andFIG. 9, once the VCT control assembly21is removed from the cavity, the VCT plug11is installed in place of the VCT control assembly21. The VCT plug11comprises an oil channel111. The oil channel111is positioned into the cavity and the VCT plug11is bolted to the engine block. The oil channel111allows the high pressurized oil to be directed to the performance camshaft12, once the performance camshaft12has been installed. However, the high pressurized oil is delivered at a constant rate, as the VCT plug11does not comprise a means for limiting the high pressurized oil through the oil channel111. In this way, the timing of the performance camshaft12is constant.

In further reference toFIG. 3andFIG. 9-10, the performance camshaft12is installed in place of the stock camshaft22. The performance camshaft12differs from the stock camshaft22in that the performance camshaft12is able to attain valve lift values that are higher than valve lift values of the stock camshaft22. This provides the reason for replacing the VCT control assembly21with the VCT plug11, as the adjustments in the timing of the performance camshaft12would cause valves to collide with pistons within the hemispherical internal combustion engine. The performance camshaft12comprises a plurality of bearing journals121, to which an assembly lubricant16is applied before the performance camshaft12is installed into the engine block. The assembly lubricant16facilitates rotation of the performance camshaft12within the engine block. Once the performance camshaft12is installed, the camshaft locating plate is reinstalled onto the engine block. In reference toFIG. 5andFIG. 11, the performance camshaft12comprises a front cam bearing that is positioned into a front bearing bore of the engine block. The camshaft locating plate is positioned around the front bearing bore. Depending on the model of the performance camshaft12to be used, the front cam bearing may have a diameter significantly smaller than the diameter of the front bearing bore and the performance camshaft12may not be of sufficient length for the front cam bearing to engage the front bearing bore. As such, the camshaft retrofitting kit may further comprise a cam adapter122. The cam adapter122is connected to the front of the performance camshaft12and acts to increase the diameter of the front cam bearing, as well as extend the length of the performance camshaft12.

In reference toFIG. 12, similar to the performance camshaft12, the performance camshaft drive assembly13is installed in place of the stock camshaft drive assembly23.

More specifically, the performance timing chain guide132is installed in place of the stock timing chain guide232, the performance chain tensioner is installed in place of the stock timing chain tensioner233, the performance timing chain131is installed in place of the stock timing chain231, the performance crankshaft sprocket134is installed in place of the stock crankshaft sprocket234, and the performance camshaft sprocket135is installed in place of the stock camshaft sprocket235. The performance camshaft drive assembly13acts to provides increased efficiency and horsepower of the hemispherical internal combustion engine as compared to the stock camshaft drive assembly23.

In reference toFIG. 6, both the performance timing chain tensioner133and the performance timing chain guide132are bolted onto the engine block using existing bolts and bolt holes used to secure the stock timing chain tensioner233and the stock timing chain guide232to the engine block. The camshaft retrofitting kit further comprises a plurality of attach-bolts18. The plurality of attach-bolts18is used to secure the performance camshaft sprocket135to the performance camshaft12. Once the performance camshaft sprocket135is secured, the performance crankshaft sprocket134is keyed onto the crankshaft. The performance camshaft sprocket135comprises a cam timing mark1351, while the performance crankshaft sprocket134comprises a crank timing mark1341. When the performance camshaft sprocket135and the performance crankshaft sprocket134are installed, the cam timing mark1351is aligned with the crank timing mark1341in order to ensure proper timing of the performance camshaft12and the crankshaft. The performance timing chain131is positioned around both the performance camshaft sprocket135and the performance crankshaft sprocket134.

In reference toFIG. 9, once the performance camshaft drive assembly13is installed, both the oil pump and the timing chain cover are reinstalled. The oil pump is reinstalled making sure that there is proper clearance for the performance chain tensioner.

The timing cover is bolted to the engine block over top of the performance camshaft drive assembly13. In reference toFIG. 13, depending on the timing cover, a portion of the timing cover may need to be removed prior to reinstallation in order to provide clearance for the performance chain tensioner. In reference toFIG. 14, the plurality of new gaskets14comprises a timing cover gasket; the timing cover gasket replacing an old timing cover gasket from the plurality of old gaskets24. The timing cover gasket is positioned in between the timing cover and the engine block when the timing cover is reinstalled.

In reference toFIG. 7-8, each of the plurality of cam followers30is a multi-displacement system (MDS) lifter and comprises a body301, a hydraulics assembly302, and a plurality of springs303. Both the hydraulics assembly302and the plurality of springs303are positioned within the body301; the hydraulics assembly302being positioned above the plurality of springs303. The plurality of cam followers30is disassembled, removing both the hydraulics assembly302and the plurality of springs303from the body301for each of the plurality of cam followers30, wherein the plurality of cam followers30is specifically eight MDS lifters. The plurality of springs303is then replaced by the plurality of spacers15and the plurality of cam followers30is reassembled. Each of the plurality of spacers15is a cylindrical extrusion of solid material. In this way, each of the plurality of cam followers30is converted from a spring activated MDS lifter to a conventional acting hydraulic lifted in order to keep the plurality of cam followers30from collapsing under the MDS actions. The plurality of cam followers30is then reinstalled within the engine block along with the plurality of pushrods.

The pair of cylinder heads, the pair of rocker covers, the intake manifold, and the oil pan are then reinstalled in succession. The plurality of new gaskets14further comprises a pair of cylinder head gaskets, an oil pan gasket, and an intake manifold gasket. The plurality of new gaskets14acts to replace the plurality of old gaskets24of the hemispherical internal combustion engine, as shown inFIG. 14, as each of the plurality of old gaskets24becomes worn over time. In addition to the old timing cover gasket, the plurality of old gaskets24further comprises an old pair of cylinder head gaskets, an old oil pan gasket, and an old intake manifold gasket. The pair of cylinder head gaskets is positioned in between the pair of cylinder heads and the engine block in place of the old pair of cylinder head gaskets when the pair of cylinder heads is reinstalled. Similarly, the oil pan gasket is positioned in between the oil pan and the engine block in place of the old oil pan gasket, and the intake manifold gasket is positioned in between the intake manifold assembly and the engine block in place of the old intake manifold gasket. The water pump, the power steering assembly, the alternator, and the air conditioning assembly are then reinstalled into the vehicle.