Zero Tolerance

Does my 2008 2.7 - 4 cyl. have one of those 0 tolerance engines where you screw up the head if the timing belt breaks ?

 

The 2.7 has a chain. I believe you are talking about an interference engine like Honda. If the belt breaks the valves hit the pistons causing big damage. Honda's newer 4 cylinders have switched to chain drive.

 

Bump for you....only because you are from my home town....
BTW...Welcome to TW!!

 

If the timing belt/chain breaks on ANY engine while it's running, you're done. If it skips a tooth... maybe not full damage. I'm not sure what the 2.7L would do if it skipped one tooth.

 

Here's an article that might help. Not all engines are interference engines. If the belt or chain breaks on a non-interference engine, there usually is not major damage.

http://en.wikipedia.org/wiki/Interference_engine#Interference

 

Toyota does not make any interference engines I believe. If our cam chains break they would not cause any damage whatsoever. We can spin our crankshaft without worrying about pistons at TDC (Top Dead Center) hitting an open valve.

 

This makes it very easy to work on and change belts on non interferance engines. When I change a timing belt or chain on an interference engine I probably mark 10 more spots on the pully/belt/casing/housing to make sure nothing goes wrong. If there is slack in the wrong spot it can cause a skipped tooth and that's an expensive repair if you crank engine without checking and pistons and valves collide.

 

I do correct my self that if A chain breaks like we have that might do some damage, not to the pistons or valves but to whatever parts the chain may hit. I don't worry much about our cam chains, I like them more then belts.

 

That is most definitely NOT true. Only "interference" engines will result in engine damage from a broken T-belt or chain.

The 2.7L Toyota engine is not an interference engine, so rest assured that your engine will not be damaged in the event of a timing chain failure. T-chains rarely break, although they are known to become derailed or skip a tooth. This is most often caused by broken guides and or tensioners. The chain might last 'forever,' but the guides and tensioner often do not.