The guide "Novel Variable Compression Ratio (VCR) Engine" offers a comprehensive analysis of the operation and benefits of engines with variable compression ratios. Unlike conventional gasoline engines that rely on a fixed compression ratio, the VCR engine allows for the adjustment of the compression ratio to meet the specific performance requirements of the vehicle. This results in improved fuel efficiency, a reduction in knocking noise, and greater flexibility in using different fuels. The author, Milind Yadav, examines the challenges of mass production due to the complexity of these engines and presents a novel concept for converting fixed compression ratio engines into VCR engines. The innovative mechanics, based on a split cylinder block, lift the cylinder head and enable the adjustment of the compression ratio. This conversion promises not only mechanical simplicity but also a significant increase in thermal and volumetric efficiency.