Sorry this may be a ridiculous question to ask, but what is the purpose when doing the timing belt install in setting the crankshaft to the TDC?

I understand the reasons why I would do this when adjusting the valves so I could adjust the valve when the piston is fully compressed, but why with the timing belt? Is it so I could go back to that position if the crankshaft or camshaft accidently move during the install of the belt? I don't think I follow why this is done.

 

It's just a point of refernce. You can do it at 19*BTDC (or whatever) if you think you can get the crakshaft postion and cam in the EXACT right position. One tooth isn't gonna ruin your motor but it'll run like ***.

 

werd. ive heard of a guy who had a 600+hp mitsu and got a shop to replace the timing belt and the intake cam was off by one degree and he could barely get to speed on the highway without flooring it.