im about to tune my car on thursday and im hella scared that my timing belt will slip

stock gsr with p30 pistons BC3+ cams and supertech valves
as far as i know the guy installed supertech dual springs part number SPR-H1002D
specs:
seat:70@33.5
open 190@12
max lift14mm


his cam gear slipped when he was tuning the car also.

so im wondering what are the most common causes of belt slipping and skipping a tooth?

 

slack not correctly taken out of timing belt

 

on a built motor should it be according to manual as well or is there something extra need to be done with bigger cams and higher pressure springs?

 

Just incase you need to redo the timing.
When doing your timing you start the belt around the crankshaft than around the tensioner than around the water pump than around the EXHAUST CAM THEN YOUR INTAKE CAM when putting the belt on the intake cam you pull down on the tensioner with the belt creating slackthan around the water pump onto the intake cam. Than turn the crank 180 degrees and tighten the tensioner. Since you made the belt snug on the intake side Theres slack on the exhaust side not to much after the belt runs down past the crankshaft the tension does its job and removes The slack than you tighten the tensioner in that position.
You could also check the deflection in the belt I don't know how much is too much but ill check later and edit
Slipping the belt past a tooth is from too much slack