I was replacing the timing belt on my new B20Z and getting it ready to drop into my car. I had a few questions though.

If I take off the timing belt can I spin the crank freely without worrying about the pistons hitting the valves? Or is there some danger that if a valve is fully open I could tap it with the top of a piston when I rotate the crank?

What are the benefits/drawbacks of advancing/retarding the timing?

What would happen if I move the intake cam forward or back a tooth? The exhaust cam?

 

someone here must know

 

I wouldn't do a complete revolution of the crank. If you need to move it to get the block set back to perfect TDC it will be fine just don't move it too much. You could tap a valve if you had the cam off TDC too. Just be careful!!!


[Modified by JDMspecEG6, 11:18 PM 8/6/2002]

 

I am nearly 180 degrees away from TDC on the number one piston. If I want to set the timing properly I would have to spin the crank 180 degrees. What if I backed off the bearing caps on the cams? That should let the valves lift up a few millimeters. At least enough to spin the crank without worrying about tapping a valve right? Is there an easier way to do this?

 

It won't matter if the valves touch the pistons when you turn it over by hand. Unless you are running extremely aggressive cams very a piston with a very high dome, then i doubt they will even touch in the first place.

 

I think I got myself out of trouble. I used the timing marks on the cam gears and the crankshaft to return the crank to the position it is supposed to be in. Then I replaced the timing belt and spun it so that #1 cylinder was at tdc.

Now that it is near where it is supposed to be, how do I set the timing correctly. Do I just line up the little notches on each side of the cam gears so that they are even with the valve cover gasket? What about the crank pulley? It has 4 notches on it. Three that are right next to each other and another notch that is right next to those. How do I line up these notches?