Q: Connector rod vs compression ratio

asked by on January 16, 2017

does connecting rod length have an effect on compression ratio?

The short answer would be yes, the connecting rod does have a direct affect on the compression ratio. For example, if you were to use a shorter connecting rod in a given engine when doing a rebuild, a piston manufacturer would suggest a piston design that has the connecting rod pin located lower on the skirt, in order to maintain the same compression ratio. If a longer rod were being used, than what was removed, the piston design would have the pin location closer to the top of the piston, closer to the rings. Of course, there are limitations when making these kinds of modifications. Piston designers will take into account the skirt design, piston ring layout, and several other factors. There are several good technical articles that can be found by companies such as Callies, GRP, Sealed Power, TRW, Arias, Wiseco, and many more.

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