Hello, I am manu5, I suppose you talk about the F9Q engine, to block the crankshaft you have to take a screw with a glass of just low glass from the oil recuperator. There you put a 7mm drill if I remember correctly and you are turning the crankshaft pressure with the drill until you find the site that is blocked. The camshaft is left with a brand that is pointing to the upper part, if you look at the camshaft lid see that wears a notch, usala of reference. Assemble the strap with a line at the point of the camshaft, another in the piñon of the cyguñal that also carries and the remaining is the pump. Then turn 2 laps and check that there are no mechanical shocks. Turning 2 laps, the lines can never match you with the points because the belt makes its different cycle. I hope the information serves you, there I would exchange the 2 most tensioning crazy rollers. all the best. Manu5.