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What do you guys make of this? The compression ring end gap appears to have been eroded?
The chrome plating is also breaking down, which caused the cylinder wall wear you see.
Or was it the other way around???
Looks pretty typical of a high mileage engine. The top ring always wears out and allows the combustion blowby you see on the piston. These engines could have benefited if they were made with an additional ring set.
Do not take this as gospel because I am not an expert but I've torn apart many of these that are very worn and the piston-to-wall clearance is extremely loose. Ancient alien theorists speculate that this allows the piston to rock in the bore at top dead center when the thrust load changes direction - thus causing the piston ring to run off-perpendicular to the cylinder wall and the corner of the ring (rather than the flat face) to run on the bore surface.
The taper of the bores on highly worn cylinders has been nearly .020" on a couple I've had machined. That's like running standard pistons in a bored block when the piston is in the top third of the bore.
Could someone point out the end gap in that pic? I can't see it.
