"Out Of Phase" and "Piston "Throw"

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vekenti

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Can someone explain to me what out of phase and piston throw is? please and thanks , N.J.M
 
"out of phase": This has two meanings:
1. Static: Camshaft angle does not match crankshaft angle. eg when the timingbelt is replaced incorrectly. This causes the valves to open and close at the wrong times. Can lead to engine failure if valves collide with the piston, wont start otherwise.
2. Dynamic: Valve position does not match crankshaft angle. When rpm is very high, the valvetrain wont be able to perform the original timing due to mass inertia. This causes pushrods to flex in OHV engines. And valve springs will be too weak to close the valve on time due to inertia. Performance decreases at high rpm, danger of collision with pistons (applies to OHC Engines, too).


"piston throw": The conrod is broken by means of broken into (several) pieces.
Eg. defect in manufacturing (very rare), deficient lubrication over a long time or low oil pressure over a long timeor or over-rev. Engineering faults with performance-tuning or factory-tuned "performance" engines (japanese!!). Leads to engine failure.
 

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