I'm changing the timing and balancing belts on my F22A1 Accord. The old belts are already off so I won't be able to use the CAM gear or balance-shaft timing marks for TDC verification. I thought the job was done when I found something confusing on the final check. The F22A1 has a viewing portal for checking crankshaft timing (see photos). I found a mark that I initially thought was TDC so enhanced it with a white marker (figure 1). When I turn the crank pulley CCW, I see the red-color 15-degrees BTDC ignition timing marks (fig 2). If I continue turning the crank pulley CCW slightly further, I see a mark that looks like a cross (figure 3). When the timing mark is on the cross marking, the crank pulley arrow seems to point to a mark on the oil pump housing (figure 4). I now think the cross mark is the actual crankshaft TDC location. Here's my reasoning: since this engine rotates CCW, I expect the 15-degree-BTDC marks to appear shortly before the crankshaft TDC mark; the cross mark meets this criterion. Also, the marks on the crank pulley seem to confirm this reasoning.

I'm pretty sure the cross mark on the flywheel is the actual crankshaft TDC but was wondering if anyone has a different opinion. Does anyone know what the figure-1 white mark represents?

 

Not sure why I didn't think of doing this before. I put a long screwdriver into the cylinder-1 spark plug hole and watched it rise and fall as I turned the crankshaft CCW. It's TDC when the screwdriver reaches the highest point. I've confirmed TDC is when the indicator is at the cross mark (i.e., figure 3).

 

I tried to find a photo of the marks but nothing on the web other than it is a zero or a T