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Mechanical Failure

Practical Engine Building

Discussion and questions related to the course Practical Engine Building

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When sourcing components for a build, is there a way of determining, or finding documentation for the maximum horsepower and RPM rating for OEM components?

So if I were to want to build an engine for high rpm and aftermarkets were limited for crank selection etc.

Good question - I hate the use of, by many suppliers, of the 'power' rating for parts, especially when the same part is supposed to be used for high rpm N/A and high torque forced induction engines, which have very different compressive and tensile loadings. Similarly, transmission parts that give 'power' but not torque capacity or rpm limit. This sort of thing was addressed in a recent HPA video.

First step may be to check on-line for any sites for that make, model vehicle and/or specific engine. They would have direct experience to go by, especially for the OEM stuff. You mentioned crankshafts, some engines have very stout stock cranks being forged from the factory, others have strong nodular cranks - and some have relatively weak ones.

If you're going aftermarket, give some thought to the maximum rpm the engine will ever see, and the parts you're expecting to use, and contact the manufacturer directly. For example, if looking at connecting rods, it'd help if you had the piston weight, stroke, rod-stroke ratio, centre to centre length, 'boost' if forced induction/estimated peak torque for compressive loading, maximum rpm, etc, for them to estimate the actual loadings the connecting rod will need to accommodate - oh, plus things like block clearance, width, and all that other stuff. Many aftermarket specialists will have on-line forms you can fill out when inquiring about parts, too.

Do you have a specific engine in mind?