I have a 05 camry with 2.4 engine. Engine was recently swapped with a parts car engine. The upper oil pans needed swapped which means the balance shafts were swapped. I originally retimed them via timing marks and TDC. There is a bad vibration and after research on the toyota forums it needed to be at BDC.
This got me thinking. What is BDC? TDC is top on compression stroke of the #1. The crank is at the bottom each revolution but twice each combustion cycle.
So What is BDC?
this brings me to another question. Where did TDC come from. Top Dead Center. My thought is it has to do at the time when the crank stroke is aligned in the center of the rotational circle of the engine? Top Dead Center is when it is aligned on the top side with the piston closest to the head and Bottom Dead Center is when it is aligned on the bottom and the piston is furthest from the head.
Anytime i think of TDC I assume it is always on the compression stroke. Maybe I have just conditioned myself to make that assumption and it is actually refereed to TDC on the compression stroke.