most likely a bent connecting rod.
A copper bond in the piston skirt refers to a layer of copper alloy that is applied to the piston skirt during the manufacturing process. This layer helps to improve thermal conductivity and reduce friction between the piston skirt and the cylinder wall, ultimately enhancing the overall performance and durability of the piston assembly.
Piston crown is the top, skirt is the side below the ring lands (ring grooves). The as you say, the skirt often has cut aways to clear the counterwieghts on the crankshaft.
That is not a knock, that's a piston skirt slapping against the cyslinder wall. It is either #2 or #4 piston, and if you remove the piston you will find that all the moly coat has been rubbed off the skirt. A new piston is what you need.
Poor lubrication. Excessive rpm's. Defective piston. Problem with the wrist pin, bushing or piston rod.
There is the penis, the testicles, the scrotum, the prostate, the sperm duct etc.
most auto mechanic preferred .002 clearance from piston skirt to sleeve
A larger piston skirt to cylinder wall contact raises piston cooling. With turbo motors, they have piston oilers, they spray oil on the underside of the pistons, cooling the piston /crown.
The piston is prevented from tipping in the cylinder by the piston rings, which provide stability and guidance as the piston moves up and down within the cylinder. Additionally, the piston skirt design and cylinder wall clearance also help to maintain proper alignment of the piston during operation.
low oil and a loose piston skirt
Aluminum expands much more than Cast Iron, so when the piston to cylinder wal clearance is measured at room temperature there must an allowance to allow for expansion when the piston heats up. The amount of clearance depends upon the design of the engine and the anticipated operating temperature. Air-cooled engines run very hot so they require more clearance than water-cooled engines. On a Cushman piston the reference point for more clearance than water-cooled engines. On a Cushman piston the reference point for clearance measurements is at the top of the skirt perpendicular to the piston pin All areas of the piston do not expand the same; the top of the piston runs the hottest so it expands the most. The skirt runs the coolest so it expands the least. For this reason the diameter at top of the piston will normally be smaller, and the diameter at the bottom of the skirt will normally be a little larger, than the diameter at the top of the skirt. Also, the piston does not expand the same all the way around its circumference. The diameter measured across the piston pin will expand more than the diameter-measured perpendicular to the piston pin. Therefore, the piston is "cam ground", or made slightly oval, with the smaller diameter measured across the piston pin. When the piston heats up to operating temperature it will then be round. If the piston were not cam ground, the to operating temperature it will then be round. If the piston were not cam ground, the piston to cylinder wall clearance would have to be extremely high when the engine was cold to allow for expansion, and it would not be round when at operating temperature. This could cause piston slap and other problems. piston to cylinder wall clearance would have to be extremely high when the engine was cold piston to cylinder wall clearance would have to be extremely high when the engine was cold to allow for expansion, and it would not be round when at operating temperature. This could cause piston slap and other problems Cushman engines are usually set to a clearance of about .006 inch measured at the reference point described in paragraph one. The clearance at operating temperature will be much less, and if sufficient allowance is not made for expansion, the piston will expand to much less, and if sufficient allowance is not made for expansion, the piston will expand to the diameter the cylinder wall and freeze up. During break-in everything is running extra the diameter the cylinder wall and freeze up. hot due to the increased friction, and the piston temperatures get very high. If the engine is run at high speeds during this period it will almost always freeze up and may damage the run at high speeds during this period it will almost always freeze up and may damage the engine The following measurements are from a Cushman NOS +.030 cam ground piston Top of skirt perpendicular to the piston pin 3.024 (.006 clearance) Top of skirt measured across piston pin 3.011 Bottom of skirt perpendicular to pin 3.025 Bottom of skirt parallel to piston pin 3.012 Top of Piston and ring lands 3.005 In this case the clearance to a nominal 3.000 inch cylinder bore is .006 inch, the elliptica amount is .013, the skirt is .001 larger at the bottom than at the top, and the top of the piston is .019 less than the widest point on the skirt. These measurements are for llustration only and individual pistons may vary considerably
PVC stuck open.Bad rings calapsed,Busted piston skirt.
A solid-colored top in any color that is in the pattern on the skirt.