d318 cat engine

1-5-3-6-2-4
Flywheel should have marks with cylinder pairs 1&6, 5&2, and 3&4, but be aware that the flywheel can be installed incorrectly.

The best way to be sure is to watch the rocker arms. At TDC one set will have clearance and the mateing set will be "On the rock" meaning Exh closeing and Intake opening. You can put #6 rockers on the rock and set#1 I&E,#2 I,#3 E.#4 I and #5 E. Then turn the crank 360 Deg and set #6 I&E,#5 I,#4 E,#3 I and #2 E or set them individually as you bring each piston to TDC.
Later Bob

just where are you suppose to look for these marks is thier a cover hole or look through where you adjust the clutch

Right front side of the clutch housing sort of near the engine oil dipstick.

look for a small cover held on by a couple of bolts. Should be a pointer in there and marks on the front of the flywheel. You can do it all from the top if you want, just watching the rocker arms like Bob says.

thanks for the answers while i had the head off i marked tdc on #1to adjust by what i was doing was to see if all the marks lined up properly for future use thanks for the help jw45

thanks for the answers while i had the head off i marked tdc on #1to adjust by what i was doing was to see if all the marks lined up properly for future use thanks for the help jw45