Patent Publication Number: US-2019186412-A1

Title: Rebuildable Engine Casing and Oil Squirter Assembly for Air Cooled Internal Combustion Engines

Description:
BACKGROUND 
     Technical Field 
     The present invention generally relates to the Field of casings for internal combustion engines and more particularly, to rebuildable engine casings and oil injection nozzle assemblies. 
     Background 
     Internal combustion engines having a plurality of pistons have been used for years to provide power to vehicles. Typically, these engines arc built with an external casing, also known as an engine case, that is formed and machined to both protect and support the internal engine components, including the reciprocating pistons and piston rods. They also provide oil passageways or oil galleries allowing for motor oil to move throughout the engine to lubricate and cool the internal components. These engine casings generally include a pair of opposing case halves but may include other pieces to provide the desired support and a protective outer housing. Typical uses for such internal combustion engines are for powering vehicles, including automobiles. 
     To maintain performance and life, these engines may require servicing of their internal components. Moreover, the internal components and moving parts of all such internal combustion engines, eventually wear out. That leaves the option to replace or service the internal engine components. Alternatively, the entire vehicle is simply replaced due to the high cost of engine servicing. 
     In certain applications, including expensive, performance engines, servicing or rebuilding the engine is preferred. Moreover, rebuilding allows customization. Rebuilding necessarily requires the engine be taken apart, inspected and the internal components, repaired and serviced. A thorough cleaning of the engine is nearly universally recommended. 
     Generally, a first step in rebuilding and engine starts with separating the engine casing halves and any other members. Current methods of separating the members, however, are slow, considerable work and a challenging process. After the casing fasteners are removed, the casing members are slowly and methodically pried or otherwise worked apart. In addition, these efforts can leads to, damaging or warping the mating surface, which in turn leads to increased costs and rebuild time to repair and machine the damaged or warped surface. In addition, the case members can he damaged or even cracked while trying to separate the case members leading to the need to replace the expensive casing member. What is needed is an improved engine casing system and method that facilitates separating the engine casing members. 
     Another difficult aspect of servicing and rebuilding currently designed engines is servicing the oil passageways or galleries. While it is desired to thoroughly inspect and clean these galleries of oil residue, varnish and any debris, the lack of access to the galleries makes such cleaning difficult. What is needed is an improved engine casing that provides better access to the oil galleries to facilitate servicing and cleaning. 
     Many internal combustion engines use oil spray nozzles, often referred to as oil squirters to, lubricate and cool the pistons and lower piston cavities or chambers. In a typical application, the internal combustion engine, includes oil squirters adapted to spray oil into the piston cavity or even against the underside of each piston during operation. Each oil squirter assembly is a separate internal component that is press fit into a bore that is formed as part of an oil gallery connecting it to the oil pump. 
     As noted, a first problem with currently availably air cooled, internal combustion engine casings and particularly when rebuilding them is separating the case or casing members. As also noted, a second problem when servicing or rebuilding them is accessing the oil galleries for servicing and cleaning. Another problem is identifying and repairing clogged or even plugged oil injection nozzles or squirters. Or even servicing the oil squirters to ensure they are operating as originally designed. Moreover, these oil squirters are a fixed design and not serviceable components. They are neither repairable or rebuildable. 
     Common efforts to clean, existing oil squirters include spraying or soaking with a chemical cleaning agent into an open end of the nozzle, waiting, repeating and using compressed air to clear the oil passageway. Others have used thin wire and solvent to first inspect and then physically clear any debris or obstructions. While these solutions may clear obstructions, they may also unwittingly damage the internal spring and plug or valve assembly. One is also unable to truly know how clear the nozzle passageway is or the actual its condition and stability of the nozzle, without removing and physically inspecting each one. Moreover, these cleaning efforts require significant time and risk of damage to the desired flow and stability characteristics of each nozzle. 
     Removing and replacing injection nozzles when rebuilding is possible but requires significant time, effort and possibly even specialized tools. These efforts may include machining, drilling out each pressing in nozzle and then pressing in a replacement one. Such efforts have the risk of leaving metal debris within the oil passageways. Moreover, if replacing, one risks altering the desired orientation, flow and stability of each nozzle. And replacing increase the chance of damaging the much more expensive and difficult to replace engine casing. What is needed is an improved engine casing and oil squirter that facilitates rebuilding and the servicing and cleaning of the squirters. 
     SUMMARY 
     The present invention provides a rebuildable engine case, also referred to as an engine casing, for an air cooled, internal combustion engine supporting internal engine components, including reciprocating pistons. The engine casing Rams and provides oil galleries, often referred to herein collectively as an oil gallery, that allows oil to move from an oil pump source to every piston cavity or chamber and back again. 
     The engine casing includes a first case member or casing half that has a flat planar mating surface at one end. The engine casing also has an opposing case member or opposing half that also forms a second flat mating surface. The case members form shell like structures as is common in the art. The two planar mating surfaces are adapted to fit together to form a sealed housing for the engine components. The mating surfaces are also specifically designed to be separated from each other to facilitate servicing and rebuilding of is the engine without some of the challenges and difficulties common with current engine casings. 
     The engine casing provides an integrated mechanism and method for separating is the engine case members to facilitate servicing or rebuilding the engine internals. This mechanism provides threaded bores within and passing through the mating surface of one of the engine casing halves. Each bore being substantially perpendicular to the flat mating surface. The bores are designed to mesh with a threaded pushrod or even an engine bolt such that when threaded into the bore, the pushrod contacts the opposing mating surface, or adjacent to the mating surface. As the pushrod is further threaded into the bore, it increasingly presses against the mating surface of the second engine case member. The engine case members are secured together at their mating surfaces using fasteners as known in the art. These fasteners must be removed before actuating the case separating mechanism. 
     The engine casing further, incorporates internal structures forming oil galleries, piston chambers and support structures for the various internal engine components. The internal structure of the engine casing includes an internal bore cylindrical oil squirter port that is adapted to receive an oil squirter and preferably, the novel oil squirter a the present invention. In one embodiment, an oil squirter is inserted into each cylindrical squirter port and secured using a temperature sensitive adhesive. 
     As noted, the oil squirter has a tubular body that fits within the internal bore of the casing. More specifically, the tubular body has one end, referred to its a receiving end, that is adapted to be inserted into the squirter port so that it creates a continuous oil passageway from the oil gallery through the hollow tubular oil squirter body. The internal passageway of the receiving end includes structure that can work with an inserted valve or plug to control the flow of oil through the tubular body. The tubular body extends along the cylindrical axis of the squirter port to a second end, referred to herein as the discharging end. The discharging end may advantageously be fitted with an outwardly protruding flange and internal threads. 
     A removable oil squirter cat is connected to the discharging end of the tubular body. This cap extends from the discharging end of the tubular body into the piston chamber and includes a passageway extending from passageway in tubular body and out through a second end having an mice such that it when it receives oil from the tubular passageway, that oil can be squirted out of the orifice and into the piston chamber. The oil squirter cap has a first or receiving end that is adapted to be both attached and removed from the discharging end of the tubular body such that is can be removed to service the oil squirter assembly during an engine service or rebuild. Preferably, the receiving end of the cap is fitted with external threads that fit within and mesh with mating internal threads within the discharging end of the tubular body. 
     In addition to the orifice, the second or external end of the squirter cap also includes a mechanical configuration that allows use of a mechanical tool when installing or removing it from the tubular squirter body. The mechanical configuration may be a screwdriver groove within the top exterior surface of the cap. The second end of the squirter cap is configured as a flange relative to the first end. The flange configuration cap is adapted to but up against the external flange on the discharging end of the tubular body. 
     A coil spring and plug or valve member are fitted within the tubular body and secured in place by the cap. The spring and valve control the flow of oil through the oil passageway. A variety of different springs and valve members are contemplated. 
     The engine casing also includes a threaded opening or port that directly accesses an oil gallery. This threaded opening includes interior threads within the wall of the casing member, which are designed to mesh with a threaded oil gallery plug. The plug includes external threads that can be threaded into or removed from the oil gallery servicing port to improve and simplify servicing of the oil gallery and oil components along the path of the gallery. 
     The present invention further provides an engine casing for an air cooled internal combustion engine having rebuildable oil squirters that, are manufactured as part of the engine casing. These integral oil squirters eliminate the need for multiple parts and are similarly serviceable through a novel removable oil squirter cap. 
     In this embodiment, the engine casing is designed and machined such the internal oil squirter bores are machined to the same tolerances as the tubular body of removeable oil squirter. This embodiment of the oil squirter bore includes internal threads machined into the engine casing at the discharging end and a valve seat at the base of the bore or the receiving end. A flat surface, like a flange on the removable squirter, is machined into the engine easing at the exit end of the squirter bore within each the piston chamber. A spring and valve member are inserted into the squirter bore and the novel squirter cap of the present invention is threaded into the squirter bore. Not only can the squirter cap be removed to clean and service the squirter passageway, internal components and even the access the oil gallery passageway, it can also be changed out for a new cap to alter the orifice configuration or direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of an engine casing of the present invention. 
         FIG. 2  is an end view of the engine casing of  FIG. 1  showing case members separated. 
         FIG. 3  is a side view of the engine casing of  FIG. 1 . 
         FIG. 4A  is an end view of a case member of the present invention as also depicted in  FIG. 4B . 
         FIG. 4B  is an internal side view of a first member of the engine case of the present invention. 
         FIG. 4C  is an opposing end view of the member of the engine case of  FIG. 4B . 
         FIG. 4D  is a cross sectional bottom view of the engine case member depicted in  FIG. 4B  showing a removable oil gallery plug of the present invention. 
         FIG 5  A is an end view of a second case member of the engine casing of the present invention. 
         FIG. 5B  is an internal side view of the second member of the engine casing of the present invention. 
         FIG. 5C  is an end view of the second member of the engine case depicted in  FIG. 5B . 
         FIG. 6A  is a partial detailed view of the engine case depicted in  FIG. 1  showing an embodiment of the case separating mechanism of the present invention. 
         FIG. 6B  is a partial detailed view of the engine case of  FIG. 4  showing the removable oil gallery plug of the present invention. 
         FIG. 7  is an exploded view of one embodiment of the piston oil squirter of the present invention. 
         FIG. 8A  is a top view of piston oil squirter of the present invention. 
         FIG. 8B  is a side view of the piston oil squirter of the present invention. 
         FIG. 8C  is a bottom view of the piston oil squirter of the present invention. 
         FIG. 9  is a cut away side view of the housing for an embodiment of the piston oil squirter of the present invention. 
         FIG. 10A  is a side view of an embodiment of the cap of the piston oil squirter of the present invention. 
         FIG. 10B  is a cross sectional view of an embodiment of the cap of the piston oil squirter for the present invention. 
         FIG. 10C  is a top view of an embodiment of he cap of the piston oil squirter for the present invention. 
         FIG. 11A  is a side cut away view of an engine casing for a piston engine showing the placement of the piston oil squirter of the present invention. 
         FIG. 11B  is a partial view inside a piston engine casing showing the placement of the piston oil squirter of the present invention. 
         FIG. 11C  is partial cross-sectional view of the internal walls of one portion of the engine casing of the present invention showing a preferred location of the piston oil squirter. 
         FIG. 12A  is an external perspective view of a first half of an engine casing of the present invention. 
         FIG. 12B  is a detailed perspective view of the half of an engine casing of  FIG. 12A , showing a preferred location for an embodiment of an integrated piston oil squirter of the present invention. 
         FIG. 12C  is a further detailed view of  FIG. 12B , showing, an exploded, view of the embodiment of the piston oil squirter of the present invention, 
         FIG. 12D  is a partial sectional view of the engine casing of  FIG. 12A  showing the bore connecting the integrated oil squirter to the main oil gallery. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1  of the drawings, the present invention is directed to a rebuildable engine case  1  or housing, also referred to as an engine casing, for an air cooled, internal combustion engine supporting a plurality of reciprocating pistons (not shown). Like existing engine cases, the engine casing  1  of the present invention forms and provides supporting structure for internal engine components, including the pistons, piston rods and crank (not show). The engine casing  1  also forms internal oil passageways or galleries, often referred to herein collectively as an oil gallery, that allows oil to move from the oil pump (not shown) to every piston and piston rod chamber  3  and back again. The improved engine case allows improved access to repair and rebuild the engine components it supports and houses. 
     Referring no to  FIG. 2 , a preferred embodiment the engine casing  1  is formed from two case member halves  5  and  9 . Other embodiments may include additional or differing configurations of case members to form the same engine casing of  FIG. 1 . In this preferred embodiment, a first case member  5  or case half is designed to be mated to and secured against an opposing second case member  7  or half. A gasket (not shown) or other sealing agent may be used to seal the case members together. More specifically, the first or left case member  5  includes a flat planar surface  9  and the opposing second or right case member  7  is formed having an opposing or second planer surface  11 . The opposing right and left mating surfaces  9  and  11  are designed to mate and be secured and sealed to each other with the casing member bodies  5  and  7  extending away to form the rebuildable engine casing of the present invention as shown in  FIG. 1  and  FIG. 3 . The use of the terms first and second or right and left are only used herein to designate the opposing pieces and not to any specific engine application. 
     Referring now to  FIGS. 1 through 3  and as further illustrated in  FIGS. 4 and 5 , left case member  5  and right case member  7  include opposing attachment points  13  along or adjacent to the mating surfaces  9  and  11 . In a preferred embodiment, the attachment points of the case member, are bolt holes or bores spaced apart along each opposing planar mating surface  9  and  11  to allow the use of bolts or other threaded fastener. In another embodiment, fastener holes or bores  13  are spaced apart along one of the planar surfaces  9  or  11  and the opposing planar surface has mating bores with internal threads for receiving an engine case bolt (not shown). Alternatively, the engine casing members  5  and  7  may be secured together using any method or means that can also be removed to allow for the separation of the members from each other for service or rebuilding. 
     Referring now to  FIGS. 1, 3 and 6 , the engine casing  1  of the present invention also provides an integrated case separating mechanism  15  and method for separating the engine case members  5  and  7  to allow for servicing or rebuilding the engine internals. In a preferred embodiment, the engine casing  1  includes a plurality of case separators  15  spaced apart along or adjacent to the mating surfaces  9  and  11 . Traditionally, splitting or separating the engine housing members was tedious and often resulted in damaging the mating surfaces or worse, cracking one of the casing member. The case separators  15  of the present invention advantageously allow the case members  5  and  7  to be slowly and methodically separated while substantially reducing the risk of damaging the case members or mating surfaces. In other embodiments having additional casing members, the case separators  15  of the present invention are spaced apart along the mating surfaces of all these casing members. 
     Referring now to  FIG. 6A , in a preferred embodiment, each case separator  15  includes an internally threaded bore  17  passing through the planar mating surface  9  or  11  of one of the case members  5  or  7 . The threaded bore  17  is axially perpendicular to the planar mating surface  9  or  11  it passes through. The threaded bore  17  is axially aligned such that when an externally threaded pushrod, bolt or similar device  19  is threaded into it, the pushrod end  20  contacts against the opposing planar mating surface  9  or  11  of the opposing case member. Preferably, the alignment is such that the maximum surface area of the pushrod end  20  contact the mating surface  22 . To support the force of the pushrod  19  pressing against it. the opposing case member  5  or  7  may have a hardened or specialized surface  22  aligned where the pushrod end  20  contacts it. 
     In a preferred application, a threaded bolt  19 , such as a hex head fastener is provided within each threaded bore  17 . A temporary thread locking adhesive or similar may be applied to prevent the bolt  19  from coming unthreaded during engine transportation and use. Whenever the engine casing  1  is desired to be serviced or rebuilt, and opposing case members  5  and  7  separated, the threaded fasteners are individually threaded further into the bore  17  of case ember  7  such that the bolt increasingly presses against the mating surface  22  of the opposing engine case member  5 . The case separators  15  are preferably positioned near or even adjacent to the fasteners used to secure the case members Obviously, the fasteners securing the engine case members  5  and  7  (not shown) would first be removed or at least substantially loosened prior to substantially actuating the case separator  15 . 
     Preferably, the case separators  15  are each incrementally actuated, one at a time, such that the force exerted by them on the opposing case member, is evenly distributed across the planer mating surfaces. In a preferred embodiment, the pushrods  19  are actuated (threaded inward) in a cross pattern similar to tightening lug nuts on a wheel assembly. In a preferred embodiment of the engine casing  1 , where the case separators do not include pushrods, the threaded bores  17  are of a standard fastener size, such as ¼ inch or 8 mm diameter, allowing a user to readily obtain and utilize such sizes. 
     Referring now to  FIGS. 1, 4D and 6B , the engine casing  1  also provides internal structures forming oil galleries to allow for the passage of engine oil. More specifically, the engine casing  1 , when assembled, is formed having and provides a series of oil galleries  24 . As known in the art, the oil galleries connect to form passageways for engine oil to move to and from the oil pump (not shown) throughout the engine to cool and lubricate internal components (also not shown). As is also known, these oil galleries require cleaning and servicing particularly, when rebuilding the engine and that accessing them for a thorough service and cleaning is very difficult if not impossible. The engine casing  1  of the present invention advantageously provides for cleaning these oil galleries  24  by providing a cleaning port  26  at an accessible location  28  within the engine casing  1 . Preferably, the engine casing  1  includes a plurality of cleaning ports to facilitate the cleaning and servicing of all the oil galleries not otherwise accessible. 
     In a preferred embodiment, the cleaning ports  26  are cylindrical bores having internal threads. The bores fluidly connect with an oil gallery  24  and are preferably located within a section of the engine casing  1  and sized to allow access for serving, including the use of pneumatic and vacuum tools. 
     An oil gallery plug  30  is used to seal each oil gallery port  26 . In a preferred embedment, the plug  30  is a conventional threaded plug having external threads that mesh with the internal threads of the service port  26 . Thread sealer and adhesive may be used to ensure the plug  30  and port seal and the plug does not become prematurely loose. To access the oil galleries  24  during servicing or rebuilding of the engine, the gallery plugs are simply unthreaded from the oil gallery ports. 
     In addition to oil galleries, the present engine casing provides for conventional oil nozzles or, squirters. The internal structure of the engine casing  1  includes an internal bore or cylindrical oil squirter port that connects the oil gallery to each piston chamber. This internal bore as shown in  FIG. 11C  is adapted to receive an it squirter as conventionally known. 
     Referring now to  FIGS. 7 through 10 , a preferred embodiment of the present invention includes a novel oil squirter assembly  34  of the present invention. In this embodiment, the oil squirter  34  is preferably slip fit into each cylindrical squirter port  32 . A high grade and high temperature adhesive is used to secure the squirter  341  within the bore  32 . Preferably an aircraft grade metal adhesive such as that currently available from Henkle under the name Loctite  640  may be used. If needed, the oil squirter assembly  34  can be advantageously removed using heat, above the highest engine temperature and adhesive rating, to break down the adhesive and allow removal without destruction of the squirter as in the prior art. The squirter  34  can then be serviced and reinserted using new adhesive. The present squirter assembly  34  may be used to replace existing oil squirters when rebuilding many prior art conventional air cooled multiple piston engines or as part of the engine casing assembly  1  of the present invention. 
     The oil squirter assembly  34  has a tubular body  36  that, as noted, tits within the internal bore of the casing member. More specifically, the tubular body  36  has a receiving end  38  that is adapted to be inserted into the squirter bore or port  32  so that it creates a continuous oil passageway  39  from the oil gallery (not shown in  FIG. 7 ) through the hollow tubular oil squirter body  36 . In a preferred embodiment, the exterior surface of the tubular body  36  is tapered at the receiving end  38  inward towards the adjacent oil passageway  39 . The taper  38  advantageously facilitates alignment with the oil squirter bore  32  within the engine casing  1  ( FIG. 11C ). 
     The tubular body  36  extends from the receiving end  38  within the squirter bore  32  outward along its, cylindrical axis  37  to a second or discharging end  40 . In a preferred embodiment, the second, end  40  is a flange having a larger diameter than the tubular body  36 . The flange  40  advantageously seats the oil squirter assembly  34  against a flat surface within the piston cavity or chamber or chamber  3  and aligns it within the squirter bore  32 . In another embodiment, the engine casing  1  may include a larger counter bore within the oil squirter bore  32  such that the tubular body and flanged end  40  are flush, or even, below the casing surface forming the base or side of the piston chamber  3 . 
     In a preferred embodiment, the internal passageway  39  at the receiving end  38  of the tubular body  36  forms an internal valve seat  42  and,internal threads  44  are provided within the discharging end  40 . The tubular body  36  is prefer ably made from a single piece of metal, such as a steel or other high strength metal (relative to the generally aluminum casing), but any material or combination of materials may be used that can tolerate engine stresses and temperature conditions and not be damaged during installation. For example, the tubular body  36  may have a metal outer shell with a lining or partial lining to facilitate forming the valve seat  42 , flange, internal threads or even for facilitating the function of any internal components. 
     The oil squirter assembly  34  of the present invention includes an oil squirter cap or orifice plug  46  that is removably attached to the discharging end  40  of the tubular body  36 . This oil squirter cap  46  has a first or receiving end  48  that is adapted to be both attached and removed from the discharging end  40  of the tubular body  36  such that it can be removed to service the oil squirter  34  during an engine rebuild. Preferably, the receiving end  48  is fined with external threads  49  that mesh with mating internal threads within the discharging end  44  of the tubular body  36 . A non-permanent thread, sealant and lock, such a one from Loctite or Henkel, may be used to ensure the cap  46  remains threaded within the tubular body  36  but still can be removed for servicing, such as cleaning and accessing the internal components. 
     The cap  46  has a hollow passageway  50  that extends from its receiving end  48  to an opposing external or discharge end  52 . This passageway  50  allows for the oil that is pumped into the tubular body  36  of the oil squirter  34  to pass through the cap and be pumped into the piston chamber as can be seen in  FIGS. 11A, 11B and 11C . In a preferred embodiment, the discharge end  52  includes or forms an orifice  54  that can be adapted to provide the desired oil squirting characteristics, including flow, pressure, volume and discharge direction. In the preferred embodiment illustrated, the orifice  54  is an opening machined directly within the discharging end  52  that ties into the passageway  50  passing through the cap  46 . 
     In a preferred embodiment, the external or discharging end  52  of the squirter cap  46  provides a mechanical configuration  56  that allows use of a mechanical tool when installing or removing it from the tubular squirter body  36 . This mechanical configuration  56  advantageously allows the use of a tool, such as a screw driver, other driver, or wrench, to assist in installing and removing the cap  46  with thee tubular body. In a preferred embodiment illustrated in  FIG. 10 , the mechanical configuration  56  may be a screwdriver slot or groove provided within the top exterior of the discharging end  52  of the cap  46 . Alternatively, any other tool receiving or meshing configuration may be provided as part of the discharging end  52  of the cap  46 , such as, for example, a Phillips head or Torx socket, an Allen, hexagonal or other socket or any other configuration adapted to receive a driver or other tool. 
     In the preferred embodiment shown, the discharging end  52  of the squirter cap  46  is configured to provide a flange or larger surface relative to the first end  48  of the squirter cap. During installation, the under surface of the flange  52  is adapted to contact and butt up against the outer surface of the external flange on the discharging end  40  of the tubular body  36 . The flange end of the cap  52  may also be configured as a hex head or other bolt configuration to allow use of a wrench or the like when installing or removing it. 
     The cap  46  is preferably made from a single piece, of steel or high strength metal but any material or combination of materials may be used that can tolerate engine stresses and temperature conditions. For example, the cap  46  may be constructed from a high strength durable composite, ceramic, plastic or be made from a metal with a replaceable plastic orifice. 
     When installed as illustrated, the cap  46  extends from its receiving end  48 , which is threaded into the discharging end  40  of the tubular body  36 , outwardly and into the piston cavity  3  ( FIG. 11C ). The oil passageway  50  through the cap  46  provides a continuous oil passageway that extends from the oil gallery squirter bore  32 , though the oil passageway  39  in the tubular body  36  and out through the orifice  54  in the cap  46  such that it when the, oil squirter assembly  34  receives pressurized oil from the oil gallery, that oil is squirted out of the orifice and into the piston cavity  3 . 
     In a preferred embodiment, the oil squirter assembly  34  includes a coil spring  58  and valve member  60 . More specifically, a compression spring  58  and valve  60  are fitted within the tubular body  36  and secured in place by the removable cap  46 . The spring  58  is preferably a coil spring as known in the art though a variety of different springs that can apply pressure to the valve are contemplated. The valve  60  is used to generally seal against the valve seat  42  within the tubular body  36 . The spring  58  pushing against the valve  60  seats it against the valve seat  42  as is also known. When oil pressure within the oil squirter bore  32  is sufficient to overcome the spring force, the valve  60  is pushed back from the valve seat and oil flows into the tubular body  36  and out the orifice  54  In a preferred embodiment, the valve  60  may be a sphere but any configuration that provides sufficient sealing against the valve sear t  42  may be used. The spring  58  and valve  60  are preferably made from a metal, including a spring steel, but the valve may also be made from other materials such as a plastic or ceramic. 
     The oil squirter assembly  34  is designed to serviced by simply removing the cap  46  from the tubular body  36 . The removeable cap  46  also allows flexibility when installing or modifying the internal components. For example, the described spring  58  and valve  60  may be installed either with after installing the tubular body into the engine casing  1 . Alternatively, one could wait until they were ready to actually build or rebuild the engine within the engine casing assembly  1  of the present invention to install a specific spring and valve or change out to a differing set, or even a different set of internals, allowing much greater flexibility in determining things like flow, pressure or other attributes desired from the squirter assembly. The oil squirter assembly  34  may also be cleaned while installed in the engine casing  1  or after being removed. 
     Referring now to  FIGS. 1 and 12A through 12D , the present invention further provides an engine casing for an air cooled internal combustion engine having rebuildable oil squirters that are manufactured as part of the engine casing. These integral oil squirters eliminate the need for multiple parts and are similarly serviceable through a removable oil squirter cap. 
     In this embodiment, the engine casing  64  is designed and machined or otherwise provides for internal oil squirter bores  66  that have a similar diameter as the internal passageway  39  of the tubular body  36  of the prior embodiment shown in  FIG. 9 . This is embodiment of the oil squirter bore  66  includes internal threads  68  that are machined or otherwise formed into the engine casing  64  at the opening or discharging end. Internally a valve seat  70  is provided at the receiving end or base of the oil squirter bore  66  where it joins with the oil gallery  24 . A flat surface  72 , such as a flange, is machined into or otherwise provided on the engine casing  64  at the exit or discharging end of the oil squirter bore  66  within each piston chamber  3 . 
     An externally threaded plug or cap  74  having an oil passageway and orifice is removably threaded into the mating threads within the oil squirter bore  66 . In a preferred embodiment, the external or discharging end of the squirter cap  74  provides a mechanical configuration  75  that allows use of a mechanical tool when installing or removing it from the integral oil squirter bore  66 . This mechanical configuration  75  advantageously allows the use of a tool, such as a screw driver, other driver, or wrench, to assist in installing and removing the cap  74  with the threaded bore  66 . In a preferred embodiment illustrated in  FIG. 12C , the mechanical configuration  75  may be an hexagonal socket provided within the top exterior of the discharging end of the cap  74 . Alternatively, any other tool receiving meshing configuration may be provided as part of the discharging end of the cap  74 , such as, for example, a Phillips head or Torx socket, a screwdriver or other socket or any other configuration adapted to receive a driver or other tool. 
     Similar to the previously disclosed embodiment, a spring  78  and valve member  80  are preferably inserted into the oil squirter bore  66  and the novel squirter cap  74  of the present invention is then threaded into the squirter bore. Not only can the squirter cap  74  be removed to clean and service the squirter bore or passageway  66 , internal components and even the oil gallery  24  may also be cleaned and serviced. 
     The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms or methods disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above teaching, including but not limited to, modifications to dimensions and materials.