I changed my timing belt and water pump and I might have set my crank shaft and cam shaft with my timing marks and not the TDC mark, before I took off the old timing belt. I also put the new timing belt on (without moving the crank shaft and cam shaft) and tried to start the car, but it wouldn't turn over...new battery and starter sounds just fine...car will not turn over.

I have read that the crank shaft and cam shaft need to be placed at TDC when changing a timing belt...my question is...why? Does it really matter where they are located when changing a timing belt? Isn't really the problem come if either the crank shaft or cam shaft move while installing timing belt? I don't see the logic in having everything set at TDC...there is nothing special with how the timing belt is put on and logically you would receive the same results whether the crank and cam are on TDC or not. It seems the issue is, "DON'T MOVE THE CRANK OR CAM WHEN PUTTING THE NEW TIMING BELT ON." It all comes down to gears and the timing belt being fitted to fit into the grooves...and the groves will line up and the gears still look the same whether or not the crank and cam are set up at TDC.

I look at it really logical here...lets say I replaced my timing belt 180 degrees opposite of TDC and I removed my old timing belt (WITHOUT moving the crank or cam one bit) and I place my new timing belt on...in the exact same position, matter, belt lines up perfectly with teeth, etc. What variables have changed?

 

Every camshaft and crankshaft on planet Earth is indexed to No. 1 TDC. If you try to remove and replace the timing belt with the engine in any other position, chances are good you'll throw things out of time. Then you'll get confused and have to pull off the valve cover as you try to determine when No. 1's valves are closed (which begins the compression stroke) in order to re-index the engine. also your old belt is worn and stretched out so the new belt will throw things of. by cranking your car over you most likely have damaged your valves if so you just completely screwed yourself because you couldn't have just simply set it to tdc.

 

Okay, I have spent several hours taking pictures and Photoshopping my results. I am posting 2 different collages of pictures, because it takes my crankshaft 2 revolutions to complete one cycle.

 

I have discovered in my second collage pictures, that my cam is off just a little bit. So, I loosened tensioner, removed timing belt, adjusted the cam so that the TDC marks line with the head and the word "UP" is shown in the "UP" position, then I re-placed timing belt back on, tighten tensioner, and rotated crankshaft one rotation and sure enough, all marks are perfectly aligned up. I rotated crankshaft again for good measure and it checks out just as before. I throw on valve cover casket and re-insert spark plug wires and sure enough, my car started up!

 

i figured that much remember measure twice cut once when it comes to engine components you need to do everything by the book or manual.just count your lucky stars you didn't bend any valves otherwise you would have been in a world of hurt.