Chain sprocket mark at the cam should line up with head mark when crank is at zero. Pump gets mounted at 15 atdc when locked. Locking tool fits into hole on side of pump, and holds a raised line which will be centered in hole when in right spot. Access hole is covered with a 17mm bolt, below #6 injection line. I guess it can be mounted without a locking tool if the line is centered when done. The AB timing device is recommended for final adjustment.