Can a cold piston bind in the choke of the cylinder?
This refers to a theory that when a cold engine starts the aluminum piston will expand faster than the steel cylinder and cause binding and scuffing in the upper choked section of the cylinder. Choke refers to a slightly smaller diameter tapered into the top end of the cylinder to allow for greater expansion due to higher operating temperatures at the combustion end. I don’t know if the theory is true or not, but I think there’s more to consider than just the thermal expansion coefficients of the dissimilar metals. While it is true that aluminum’s coefficient of thermal expansion is double that of steel, that alone does not predict or determine what will happen to the cylinder/piston clearance on start-up. First of all, with any temperature change aluminum (the piston) expands and contracts twice as much as steel (the cylinder). Therefore, at cold temperature the fit of the piston in the cylinder is LOOSER, not tighter, than at room temp or at operating temp. On cold startup the piston
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