what is the contact between the piston and cylinder wall like? first of all, does the piston rind stick out slightly from the piston or is it flush with the piston? there must be a very thin layer of oil coating the walls because i doubt its metal to metal contact. please explain what part of the piston actually touches the wall, and how its able to move up and down with such ease, but still be tight enough that the air full mix doesnt leak under the piston.

 

read and think

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sport_Injected &raquo;</TD></TR><TR><TD CLASS="quote">what is the contact between the piston and cylinder wall like? first of all, does the piston rind stick out slightly from the piston or is it flush with the piston? there must be a very thin layer of oil coating the walls because i doubt its metal to metal contact. please explain what part of the piston actually touches the wall, and how its able to move up and down with such ease, but still be tight enough that the air full mix doesnt leak under the piston. </TD></TR></TABLE>

yes very close..but not metal to metal....the wall clearance is measured in micrmeter...i think it's .036micr..(i forgot..) piston rings (remember the rings locate almost to the top of the piston, when piston moving up, the rings will be at the top first) has some volume to hold oil so at BDC (bottom dead center) it absorb oil and when moving those oil in the rings spread oil to wall and give piston smoother friction to TDC...yes very thin layer...thin enough to not let oil leak..that why older rings or older car...tend to have low compression test number and leak oil to compussion champer and released by exhaust valve..taht why you see some car **** out smokes while driving on the freeway or something...anyway

well i might not get the whole picture at the moment ..correct me if anyone found an error

 

btw that's not a noob question....that question requires ton of reading and experience...or watever i bet you 5 out of 10 people in this HondaTech have no idea how to explain ur question

 

the pistons should NEVER touch the wall. but sometimes it does, and causes damage to the cylinder wall
the rings are hitting the cylinder wall and they are holding the compression in

yeah looks like we need more experience in this thread


anyone have some concrete answers?


Modified by johnzm at 12:34 AM 10/21/2004

 

good question, not a noob question. to you. Anyway, its is my belief that the piston does touch the wall but not metal to metal, theres alwasy a film of oil, but the rings do touch the wall, so they make the air tight seal, also the oil actually helps make a seal as well, ask me later when i'm an engineer and i'll have a flawless response. good question.