Posted by wally on Tuesday, August 17, 2004 at 6:35PM :
In Reply to: Re: Keith, you got me... posted by Keith in Washington on Tuesday, August 17, 2004 at 0:01AM :
Yeah right, you will get no power if the valves are open when it fires (I've rebuilt dozens and worked on maybe thousands). What I was referring to was the obvious: In say a four cylinder engine, #1 and #4 are at tdc, each for different reasons, say #4 is firing and #1 has just pushed out exhaust and is now starting to pull in gas/air. At this moment, #2 & #3 are at bottom-dc, but I have no fix off the top of my head what their valves are doing, never a concern to me.
So Keith, there are two different reasons for a piston to be at TDC, and to my thinking, they ARE 180 degrees apart. You seem to imply that tdc is only for firing.