Systems and methods for combustion engines with interchangeable components are described herein. An engine sub-assembly for a gasoline powered engine can include a crankcase having an opening extending at least through an upper surface thereof, the opening being configured to receive a crank arm therethrough, and a first mounting plate configured to be coupled with the crankcase. The first mounting plate can be selectively removable from the crankcase. The opening of the first mounting plate can generally align with the opening in the crankcase when the first mounting plate is coupled with the crankcase. The first mounting plate can be configured to receive a first cylinder block and to couple the first cylinder block to the crankcase. A second mounting plate can be configured to couple with a second cylinder block that is different than the first cylinder block and to couple the second cylinder block to the crankcase.

A cylinder head [20, 120] mountable onto a cylinder block [16] of an engine [10] is disclosed. The cylinder head [20, 120] includes at least one fastener boss [28, 128] configured for receiving a fastener [24], and the cylinder head [20, 120] is securely fastened onto the cylinder block [16] of the engine [10] by the fastener [24]. A boss cutout [30, 130] is formed on a lower portion of the at least one fastener boss [28, 128] that abuts the cylinder block [16] such that a contact pressure balance of sealing pressures around the cylinder block [16] is evenly distributed.

A cylinder block for an internal combustion engine includes a metal section and a resin section. The metal section includes: a cylinder liner; head bolt female screw portions that are screwed onto male screw portions of head bolts that fasten the cylinder block and a cylinder head; crank cap bolt female screw portions that are screwed onto male screw portions of crank cap bolts that fasten the cylinder block and crank caps and columnar portions that connect the head bolt female screw portions; and the crank cap bolt female screw portions. The cylinder liner and the columnar portions are integrated with each other.

An internal combustion engine has a cylinder block and a cylinder head fixed to each other with a plurality of bolts, and a piston fitted in a cylinder bore of the cylinder block so as to be able to reciprocate. A portion of the cylinder bore having a minimum diameter in a travel range of a skirt across which the skirt travels as the piston reciprocates is located within a range facing the skirt when the piston is at a bottom dead center. A clearance between the skirt and the minimum-diameter portion has a minimum value of a clearance between the skirt and a wall surface of the cylinder bore.

A first angle portion where part of a bearing cap side wall portion is cut out and a second angle portion where part of a bearing cap bottom surface portion is cut out are formed in a region (an angle region of a bearing cap) including a part where respective extension portions of the bearing cap side wall portion and the bearing cap bottom surface portion intersect each other, and a gap is provided between the crankcase side wall portion of a journal wall and the first angle portion and between a crankcase bottom surface portion and the second angle portion.

An engine includes an output shaft, a cylinder block, a cylinder head, a cap portion, and head bolts. The cylinder block, the cylinder head, and the cap portion are fastened together with the head bolts. The cylinder block includes a cylinder portion and a plurality of output shaft supporting portions. When an outer wall face of at least one of the plurality of output shaft supporting portions is viewed along an output shaft axial direction, the outer wall face includes a first rib diagonally extending from a supporting portion of the output shaft toward one of two head bolt holes.

An internal combustion engine and related components and methods of manufacturing and implementing an internal combustion engine and related components. The internal combustion engine includes a base, a cylinder block mounted onto the base, a cylinder head mounted onto the block, and a structural overhead member mounted onto the cylinder head, such that the cylinder head is positioned between the cylinder block and the structural overhead member. At least one through-bolt positioned in a through-bolt opening, the through-bolt opening extending from the base to the structural overhead member through the cylinder block and the cylinder head to couple the base, the cylinder block, the cylinder head and the structural overhead member together.

A cylinder head [20, 120] mountable onto a cylinder block [16] of an engine [10] is disclosed. The cylinder head [20, 120] includes at least one fastener boss [28, 128] configured for receiving a fastener [24], and the cylinder head [20, 120] is securely fastened onto the cylinder block [16] of the engine [10] by the fastener [24]. A boss cutout [30, 130] is formed on a lower portion of the at least one fastener boss [28, 128] that abuts the cylinder block [16] such that a contact pressure balance of sealing pressures around the cylinder block [16] is evenly distributed.

The presently disclosed subject matter generally relates to vehicle fastening systems that include head bolts. The disclosed head bolts are adapted to be used in internal combustion engines in a wide variety of vehicles. Specifically, the disclosed head bolts are used to fasten an engine's cylinder head to the engine block housing the pistons. Advantageously, the disclosed head bolt is constructed from carbon fiber material, providing several advantages over prior art fasteners. For example, the head bolt is lightweight, temperature resistant, and exhibits increased strength when compared to conventional head bolts constructed from steel and other metals.

A cylinder head [20, 120] mountable onto a cylinder block [16] of an engine [10] is disclosed. The cylinder head [20, 120] includes at least one fastener boss [28, 128] configured for receiving a fastener [24], and the cylinder head [20, 120] is securely fastened onto the cylinder block [16] of the engine [10] by the fastener [24]. A boss cutout [30, 130] is formed on a lower portion of the at least one fastener boss [28, 128] that abuts the cylinder block [16] such that a contact pressure balance of sealing pressures around the cylinder block [16] is evenly distributed.