Abstract:
A locking engine splay cap apparatus and method of use and manufacture comprising a splay cap and an engine block base having uniquely positioned and formed slots and protrusions which integrally mate. The mating provides optimum register of the internal combustion engine main bearing caps whereby cap chatter and inward deformation is minimized. The method of use allows smaller displacement and more efficient engines to produce higher powers without compromising reliability and durability.

Description:
BACKGROUND OF THE INVENTION 
   The art of the present invention relates to automotive engine crankshaft bearing caps in general and more particularly to an improved internal combustion engine bearing splay cap which uniquely registers with the engine block whereby a phenomena called “cap chatter” is minimized. 
   Internal combustion engines in part comprise an engine block having a crankshaft which is rotatably mounted within main bearings (traditionally a split sleeve bearing shell lined with a babbitt material). As aforesaid, the main bearings are usually split into halves and further mounted within the bearing seats formed between the engine block and the main bearing caps. That is, conventional engine blocks typically have half of the seat formed within the engine block base and half of the seat formed within each main bearing cap. Each of said seats are typically notched in order to secure and prevent spin of said main bearings via a protrusion on each of said bearing shell halves. The conventional engine block half seat also has an oil port which provides a pressurized oil flow through a hole within the main bearing half within the engine block half seat. When the main bearing caps are positioned and bolted onto and with said engine block base, a complete bearing seat is formed with the crankshaft rotatably held within said split main bearings. A conventional “V” type engine block typically contains one more bearing seat than the number of cylinders divided by two. 
   Conventional main bearing caps are typically machined castings held with the engine block via two bolts or studs through separated mounting holes on each side of the half seat. That is, each bolt fits through the cap and threads into a corresponding threaded hole within the engine block. Each conventional cap typically registers or positions via a shoulder on each side (outside) of said cap. That is, a conventional engine block typically has a recessed channel machined to a width substantially representing the shoulder-to-shoulder distance of said cap. The cap intimately fits within this channel and thereby is positioned or registered. When registered, the half seats of the block and cap form an optimum and aligned full bearing seat, especially after the seats are bored. 
   Modern internal combustion engines obtain significantly more horsepower from a smaller displacement. The increased efficiency provided by a smaller displacement engine is highly desirable for contemporary vehicle propulsion. Unfortunately, the increased stresses associated with the aforesaid requires improvements in conventional engine components, especially main bearing caps, in order to provide the durability and reliability of predecessor low power designs. Although sufficient for low power output operations, conventional main bearing cap configurations present significant durability and reliability issues when utilized with modern high power engines. When utilized with a higher engine power output, conventional caps tend to lose the aforesaid register. That is, the bearing seat halves tend to deform and no longer form an optimum circular full bearing seat. When higher power is applied, conventional cap seat walls tend to deform and the wall sides near the engine block tend to move toward the crankshaft centerline. (i.e. inward) This deformation is especially possible within the prior art since the there is no registration structure prohibiting cap deformation inward toward the crankshaft centerline. Main cap register failure typically creates what is known in the art as a main cap chatter. Main cap chatter has serious operational effects on an internal combustion engine including but not limited to premature main bearing and crankshaft failure, reduced efficiency, reduced output power, reduced oil pressure, and an introduction of harmful crankshaft harmonics. 
   The present art main cap represents a uniquely splayed cap in conjunction with a uniquely modified engine block which forms the apparatus and method of installation and use, all of which uniquely register in a fashion which minimizes the possibility of cap chatter or deformation. The term “splayed” means to be spread out or further apart. Splayed main bearing caps are spread further at the interface with the engine block. In short, a splayed cap is wider than a conventional cap and typically has four instead of two bolts for attachment. Splaying the caps provides superior strength relative to conventional caps, thereby allowing for reliable use within high power output internal combustion engines. 
   Although splayed caps have been found within the prior art, said prior art splayed caps register as conventional caps and exhibit the registration inadequacies associated with the prior art. That is, they only position or register with the engine block at the outside of the cap via a shoulder on each side. Since the splay cap is substantially wider than the conventional cap, registration of the prior art cap occurs over a wider distance than desired. That is, since the shoulder to seat distance for a conventional cap may be approximately an inch, for a prior art splay cap, the shoulder to seat distance is near three inches. Since the metallic cap material (typically a high carbon steel) has elastic properties for the same modulus of elasticity (Young&#39;s modulus) and applied crankshaft force, the prior art wider registering splay cap will allow for a greater movement between the cap and seat halves. (i.e. greater strain for equivalent stress) Unfortunately, this movement results in the same undesirable cap chatter and deformation which is present within conventional main bearing caps. Also, as with conventional caps, there is no structure to prohibit inward movement of the cap seat walls. 
   The present art splay cap represents a uniquely registered splay cap apparatus and method of manufacture, installation, and use which provides the benefits of the prior art splay cap strength while further registering the cap much closer to the bearing seat in a form which minimizes bearing seat wall movement in any direction. The present art minimizes the deleterious effects of material elasticity over greater distances by utilizing cap slots which intimately mate with uniquely formed engine block protrusions near the bearing seat. The present art thereby provides a more secure lock of the cap into the block and minimizes the ability of the cap to move inward. All of the aforesaid provide greater stability and durability than prior art splay caps. 
   Accordingly, an object of the present invention is to provide a locking engine splay cap and method of manufacture and use which locks the cap with the block and eliminates the ability of the cap to move inward. 
   Another object of the invention is to provide a locking engine splay cap and method of manufacture and use which minimizes main bearing seat deformation and cap chatter. 
   Another object of the invention is to provide a locking engine splay cap and method of manufacture and use which has more cross sectional strength than conventional main bearing caps while providing a registration which minimizes deformation due to material elasticity. 
   A further object of the present invention is to provide a locking engine splay cap and method of manufacture and use which locks in with the engine block. 
   A still further object of the invention is to provide a locking engine splay cap and method of manufacture and use which reduces distortion of the main bearing bores by increasing the cap&#39;s resistance to closing under high loads. 
   SUMMARY OF THE INVENTION 
   To accomplish the foregoing and other objects of this invention there is provided a locking engine splay cap and method of manufacture and use for obtaining optimum efficiency and durability from high power engines. The apparatus and method especially minimize the cap chatter and deformation associated with prior art main bearing caps. 
   The apparatus is provided as a unique splayed cap in conjunction with an engine block base designed to intimately mate with said splayed cap. For a preferred embodiment, the splayed cap (also known as a splay cap) comprises a bottom side having a half bearing seat with a half circular form and an engine block interface of substantially planar form, a front side and a rear side having two separated cap slots translating there between within said interface (one on each side of said half bearing seat), a right side having a right side shoulder, a left side having a left side shoulder, and a top side having four mounting holes bored through said cap and exiting at said interface. Two of said mounting holes are separated and positioned between said left side and the cap half seat and the remaining two are mirrored in position between said right side and said cap half seat. In the preferred embodiment, each cap slot is positioned between said two mounting holes on each side of said cap half seat. Also in the preferred embodiment, the mounting holes nearest said right and left sides are canted outward or toward their respective right or left sides in the transition between the top side and engine block interface. 
   In the preferred form, the engine block base which mates with the engine block interface of the locking engine splay cap has the conventional attributes understood by those skilled in the art with the modifications as described herein. That is, the engine block base has the conventional engine block attributes including half seats with half seat notches for the bearing shell halves, threaded cap holes which are separated and align with the two cap mounting holes nearest said cap half seat, and a main channel which approximates the right to left shoulder distance of a traditional main bearing cap. The present art modifies the conventional block attributes by forming (usually via vertical or horizontal milling) right and left splay cap channels to the right and left of the engine block half seats with each having right and left channel shoulders respectively which respectively mate with the separated right and left side shoulders of the splay cap. Said cap channels have a width and placement which does not overlap the main channel and further forms the engine block protrusions between the cap channels and the main channel when the cap channels are formed. The engine block protrusions as afore described mate with the cap slots to provide an optimum cap register and further minimize the inward movement of the cap toward the crankshaft centerline. The present art further modifies the conventional block attributes by placing threaded splay holes within said right and left splay cap channels which follow the cant angle of the splay cap mounting holes nearest said right and left sides. 
   For the preferred embodiment, the present art splay caps and block modifications are not utilized at the end cap locations representing crankshaft input and output. For the preferred embodiment, traditional form bearing caps are utilized at the end bearing locations. Alternative embodiments may utilize present art splay caps and block modifications at more or less locations than the preferred embodiment. 
   The art of the present invention may be manufactured from a plurality of materials including but not limited to steels, high carbon steels, tool steels, stainless steels, titanium, aluminum, (and alloys thereof) and high temperature composites. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Numerous other objects, features and advantages of the invention should now become apparent upon a reading of the following detailed description taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a front perspective view of a locking engine splay cap of the present invention shown apart from an engine block. 
       FIG. 2  is rear perspective view of a locking engine splay cap of the present invention shown apart from an engine block. 
       FIG. 3  is a top plan view of a locking engine splay cap of the present invention shown apart from an engine block. 
       FIG. 4  is a bottom plan view of a locking engine splay cap of the present invention shown apart from an engine block. 
       FIG. 5  is a right plan view of a locking engine splay cap of the present invention shown apart from an engine block, a left side plan view being substantially symmetrical therewith. 
       FIG. 6  is a front plan view of a locking engine splay cap of the present invention shown apart from an engine block. 
       FIG. 7  is a front perspective view of an engine block base of the present invention showing the present art cap channels and protrusions not found on conventional engine blocks. 
       FIG. 8  is a front perspective view of an engine block base as shown in  FIG. 7  with installed splay caps of the present invention mounted thereon. 
   

   DETAILED DESCRIPTION 
   Referring now to the drawings, there is shown in  FIGS. 1-8  a preferred embodiment of a locking engine splay cap  10 . The art of the present invention represents a unique splay cap  11  and associated engine block base  54  components which collectively form the locking engine splay cap  10 . In the preferred embodiment, the locking engine splay cap  10  comprises a splay cap  11  having cap slots  18  within an engine block interface portion  16  which mate with engine block protrusions  66  within an engine block base  54  in order to minimize cap chatter and deformation under high power applications. Unlike prior art splay caps, the present art minimizes the ability of the cap  11  to move inward toward the crankshaft centerline  64  and further minimizes cap material elasticity effects, all in order to provide an optimum cap register. 
   The splay cap  11  portion of the present invention comprises a top side  12 , bottom side  14 , a front side  20 , a rear side  22 , a right side  22  having a right side shoulder  26 , and a left side  28  having a left side shoulder  30 . The bottom side  14  has an engine block interface  16  of substantially planar form with a cap half bearing seat  32  having a half circular cap seat wall  34  and a cap slot  18  on each side of said seat  32 . In a preferred embodiment said slots  18  are approximately 0.180 inch in depth and 0.260 inch in width and transition from said front side  20  to said rear side  22 . Said slots  18  are preferably separated and symmetrically positioned relative to a crankshaft centerline  64  and in a single exemplary embodiment separated by approximately 4.8 inches. Alternative embodiments may utilize more than two slots  18  positioned symmetrically or asymmetrically or further utilize slots which do not fully translate between said front side  20  and rear side  22 . Preferably said cap seat wall  34  has a cap half seat notch  52  which mates with a conventional protrusion on a main bearing shell half. 
   From said top side  12  through said bottom side  14  are cap mounting holes  36  and splay mounting holes  37 . Said cap mounting holes  36  comprise two holes, each separated and positioned between a cap slot  18  and said seat wall  34 . In a preferred embodiment, the cap mounting holes  36  are of the same diameter and separation as those found on a conventional crankshaft bearing cap supplied with the base engine block. Alternative embodiments may utilize other diameters or separations provided the engine block is modified to accommodate such. The splay mounting holes  37  comprise two holes, each separated and positioned at said bottom side  14  between a cap slot  18  and said shoulder  26 ,  30  in a preferred embodiment. Said splay mounting holes  37  preferably cant or angle toward said shoulder  26 ,  30  as each transitions from said top side  12  through said bottom side  14 . In a preferred embodiment, said top side  12  has one or more steps  15 , preferably one at each of said right  24  and left  28  sides, having an angle relative to said engine block interface  16  which is substantially equivalent to said cant angle whereby a head or nut of an attachment bolt  38  positioned through said splay mounting hole  37  may seat flush. In a preferred embodiment, said cant angle is approximately 15 degrees with alternative embodiments utilizing any angle which fits within the geometric limitations of said splay cap  11 . 
   The engine block base  54  of the present art is uniquely formed or modified from a conventional engine block base. Within said block base  54  is the conventional main channel  58  having the engine block half circular seat  46  with a block half seat notch  48  to secure the crankshaft bearing and the threaded cap holes  56  for attachment bolts  38 . The present art preferred embodiment leaves the aforesaid substantially unchanged. That is, the main channel  58  into which is seated and registered a conventional main bearing cap is kept at the depth as manufactured with a conventional engine block. A preferred embodiment of the present invention slightly widens said channel  58  approximately 0.020 inch whereby the interface with said splay cap slots  18  mate intimately with perfectly machined and true main channel sidewall  49  surfaces. Alternative embodiments may forego said widening without departing from the scope and spirit of the present invention. 
   To the right and left of the main channel  58  is a right splay cap channel  60  and a left splay cap channel  62  respectively. Said channels  60 ,  62  are preferably machined to the same depth as the main channel  58 . In a preferred embodiment, each splay cap channel  60 ,  62  is positioned and machined to a width which preserves separated engine block protrusions  66  on each side of said main channel  58  between said main channel sidewalls  49  and said splay channels  60 ,  62 . Via the aforesaid, the protrusions  66  are formed to substantially the same width as said cap slots  18  whereby each may intimately mate with a corresponding cap slot  18  and provide the secure registration of the present art. The outer walls  65  of each splay cap channel  60 ,  62  are separated a distance which substantially represents the width between the right side shoulder  26  and the left side shoulder  30  of the splay cap  11 . The preferred embodiment forms said outerwall  65  distance approximately 0.003 inch less than the width between the separated shoulders  26 ,  30  of the splay cap  11 . When assembled, this further provides an intimate mate with said splay cap  11  and engine block base  54  in order to provide yet further registration security. Alternative embodiments may reduce or increase said 0.003 inch tolerance without departing from the scope and spirit of the present invention. 
   Within each splay cap channel  60 ,  62  is a threaded splay cap hole  63  which is bored at a canted angle relative to said channels  60 ,  62  in order to substantially follow the cant angle of said splay mounting holes  37  within said splay cap  11 . That is, when an attachment bolt  38  is placed through said canted splay mounting hole  37 , it threads without binding into said threaded splay cap hole  63 . When assembled with said splay cap  11 , said cant angle provides an outward pre-load to said splay cap  11  in order to that the cap  11  is less likely to deform inward toward the crankshaft centerline. Alternative embodiments may utilize more or less than the number of threaded splay cap holes  63  specified in the preferred embodiment without departing from the scope and spirit of the present invention. 
   Further alternative embodiments of the present art replace the engine block protrusions  66  with block slots of substantially the same width as said protrusions  66  to form keyways and thereafter insert and substitute keys within said block slots to form the equivalent protrusions  66 . This alternative embodiment utilizes keys of a height, width, and length whereby said block slots and cap slots  18  are fully filled and intimately mated when the splay cap  11  and engine block are assembled. Still further alternative embodiments invert the position of said protrusions  66  and said cap slots  18 . That is, the slot  18  is placed and positioned on the engine block base  54  and the protrusion  66  is placed on said interface  16 . 
   The method of manufacturing and assembly for the locking engine splay cap  10  begins with the splay cap  11  and engine block base  54  as afore described. That is, the splay cap  11  and engine block base  54  are machined, cast, or formed to the specifications described. Obviously particular attention is paid to the dimensional specifications of the cap slots  18  and shoulders  26 ,  30 , especially including the separation width of such, whereby an intimate mate with said engine block protrusions  66  and said outer walls  65  is respectively maintained in order to assure optimum registration. In a preferred embodiment, said splay cap channels  60 ,  62  are milled within said engine block base  54  yet are not milled at each end bearing cap location where a conventional cap and oil seal would be placed. Alternative embodiments may mill said end bearing cap locations as the preferred embodiment and utilize the splay caps  11  of the present art with non-conventional oil pan sealing means. 
   Upon completing the aforesaid, the locking engine splay cap  10  is assembled with main bearings, crankshaft, seals, and oil pan substantially as a conventional cap engine as understood by one of ordinary skill within the art. That is, prior to crankshaft and bearing assembly the splay caps  11  are mated and installed, torqued with the attachment bolts  38 , and the half seats  32 ,  46  are bored to the precise bearing seat diameter desired. The splay caps  11  are then removed and upon placement of the bearings and crankshaft, the splay cap  11  is then reseated and re-mated with the engine block base  54 . The attachment bolts  38  (usually threaded studs with nuts utilized to secure said splay caps  11 ) are then inserted through said cap mounting holes  36  and splay mounting holes  37  and threaded with said cap holes  56  and splay holes  63  respectively. The cap slots  18  are intimately mated with said engine block protrusions  66  and each shoulder  26 ,  30  is intimately mated with the block base  54  outer walls  65 . Each of said attachment bolts  38  (typically via said nuts) are optimumly torqued to maintain the mate and register of said splay caps  11 . As aforesaid, the outer wall  65  mating is in compression for the preferred embodiment and the attachment bolts  38  within said splay mounting holes  37  further apply a an outward tension upon the body of the splay cap  11 . 
   Those skilled in the art will appreciate that a locking engine splay cap  10  apparatus and method of use and manufacture has been shown and described. Said present art is capable of assuring precise and secure registration of the described main bearing caps whereby cap chatter and deformation are minimized thereby providing improved engine efficiency and durability, especially in high horsepower applications. 
   Having described the invention in detail, those skilled in the art will appreciate that modifications may be made of the invention without departing from its spirit. Therefore, it is not intended that the scope of the invention be limited to the specific embodiments illustrated and described. Rather it is intended that the scope of this invention be determined by the appended claims and their equivalents.