Timing belt breakage

[Jim]

Hi all. Can someone tell me what would happen if the Timing belt broke while driving the car? Already know that with an interference engine, one can bend the valves and damage the pistons, but besides that, what actually will the engine do or what symptoms will the engine produce, loss of power, etc? Thanks in advance. Has not happened, just curious.

Topic

[Bryan]

Here’s an animation showing what’ll happen when a timing belt gives way:

Cheers!

-Hinoki

[zero]

Most modern engines are interference. It’s safer to assume they all are and the few outliers car be counted on their won.

Any time a timing chain or belt breaks, the engine is pretty much a goner. Pistons and valves don’t like to make contact. It’s cheaper to just replace your timing belt.

[Mike]

If the belt breaks, the engine will simply wind down to 0 RPM and then not restart. When trying to restart it, the starter will usually turn at a constant speed instead of going ruh-ruh-ruh like normal. Customers have described a mechanical churning noise in some cases if it grenades. Some engines the valves will harmlessly hit the pistons and make a little mark, and the stems will bend out of the way without breaking.

Other engines, the valve stems break instead instead of bending:

[David]

I bought an 89 Prelude that the belt was broken on and 10 of the 16 valves were bent, head work years ago was $400. and then put it all together and fired it up. Ran fine for 4 yrs till I sold it.

[Author]

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