I have been working on a 2011 Accord with a 4 cylinder F23A1. I had removed the cover on the rear balance shaft to replace the o ring underneath but am unsure if I realigned it correctly when I put it back together. Haven't found any posts specific to the F23A1. The gear has a notch on the outside edge but there is also a line scribed into the the face of the gear. Also the oil pump housing has two places on the housing side by side that may be the alignment marks at about 12 oclock position. See pictures. I aligned the notch to the right most mark on the oil pump housing that puts the mark on the face of the gear at about the 5 oclock position. is this right?

 

The gear that drives the actual rear balance shaft is not a 1:1 ratio. So the visible timing of the outside sprocket is always changing each time it spins.

So... The proper method is there's a plug bolt on the back side of the block, where you insert a pin. I forget the details, but search for timing-belt instructions. Something like a 6mm allen wrench or a drill bit of some particular size. That locks the shaft into the proper position to synch with the cam & crank at #1 TDC.

 

I had a bolt in place to hold the balance shaft in position when I took it apart and then back together but because I removed the cover that the belt driven gear is attached too and pulled the whole assembly off and go to put it back together I assume that when I mesh the two gears that are under the cover back together one of the pointers on the outside belt driven gear is supposed to line up with a marker on the oil pump housing although I don't understand why this would be necessary.

 

The mark at 5 o'clock is in about the right spot. Since you have the bold holding the shaft in place, the balance shaft will be properly aligned.

You make a good point about the marks not being so important. Do not forget to remove the bolt holding the rear balance shaft in place. That is very important.

 

Post #2

FSM, page 6-28

 

Thanks for the link to the repair manual that cleared some things up looks like I did it right the 1st time.