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The timing belt on my 2000 4 runner broke w/3.4 L broke while driving down the highway. I am curious if my cams can become out of phase which would throw off my "VALVE" timing; not ignition. I keep reading different posts here and there that people go back and forth with saying that they can and cannot become out of phase. If so any accurate knowledge is greatly appreciated.THANK YOU
 

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I'm not sure exactly what you are asking so I'll try to just describe the systems you mention.

1. This truck has 4 cams, two for each head. Each pair of cams is driven by the timing belt through one sprocket in each bank.

2. The sprocket drives the intake cam which is connected to the exhaust cam by a gear under the valve cover. This is a special gear that is designed to eliminate backlash, however, unless you remove a cam there is no need to mess with it. Removing cams is not part of a timing belt replacement.

2. Since the timing belt broke both cam pairs are most definitely out of time with the crankshaft. You will have to line everything up when you install the belt. Everything is well indexed and this is easy to do if you just take your time. So yes, your valve timing is definitely off, that's what the timing belt is for.

3. Each pair of intake/exhaust cams should still be timed correctly with respect to each other, since the gear that connects them is not related to the timing belt.

4. The engine is not an interference engine, so a new timing belt should be all you need to get it running again. It's wise to change the front end seals (crank, 2x cams), tensioner, idler bearing, and water pump while you are at it.

5. Maybe you've been reading about a VVTi engine with cam phasers? Your engine does not have these.
 
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