Hi,
I've been wondering about the following for quite a while... does a piston contact the cylinder wall directly or it is completely seperated by the piston rings around the total circumfence? Or only partially on the thrust side? I searched the web for hours but can't seem to find an answer to this very basic question...
Jeroen
It touches at the bottom of the piston on the thrust side , there's a machined bearing pad there on most designs
duncanwood mumbled:
And slaps about a bit when the engine's wearing.
The piston contacts the bore wall in service. It is meant to. When the bore wears and or the piston wears, you get piston slap. Initially just when the engine is cold, then as things get worse, all the time.
Search for 'slipper piston' as these have the most pronounced contact pads and you'll see where a piston is designed to contact.
HTH
does a piston
seperated by the
on the thrust
The greatest contact pressure is on the thrust side, with lesser pressure on the opposite side during the compression stroke. These 2 sides receive the greatest wear, but as the ring grooves are deeper than the width of the rings, there's also light contact on the sides in line with the cylinders. Mike.
Some pistons have offset gudgeon pins to reduce sideways thrust, wear and noise on the power stroke.
Huw
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