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Discussion Starter · #1 ·
Just thinking. In the past, when a belt or chain broke, the valves would slam into the pistons if the engine was an 'interference' engine.

I could only imagine what would happen if you're cruising along, in gear, and the electricals cut out. Electric boost to the steering goes to heck, and the engine valves on the intake side would all go to default position. Either open or closed. In either case, there is a chance the intake valves would slam against the pistons.

Whats wrong with my logic? Clearly Fiat thought of this. What truly happens? Any gearheads out there?
 

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Discussion Starter · #2 ·
Sorry, it was late at night. I meant Fiat MultiAir II 2.4 engine mostly. Not the MultiJet.
 

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@JFS

I'm not a mechanical wizz or anything, but I'm not aware of any new technology that keeps bad things from happening when a timing belt goes.

full disclosure: I've never done any significant tinkering with anything that didn't have a carburetor.
 

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@JFS

I'm not a mechanical wizz or anything, but I'm not aware of any new technology that keeps bad things from happening when a timing belt goes.

full disclosure: I've never done any significant tinkering with anything that didn't have a carburetor.
With a time by chain and non interference design, you are unlikely to break the chain, but if you do, your valves don't smash into the pistons. So there's labor to get things back to normal, but not rebuilding the engine.

The 2.4 from what I found is timing chain and interference design.
 

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Timing chains do stretch.
And after they stretch, the wear accelerates.
And they do break.
With an interference engine, you're totally screwed.


The Land Rover Freeloader was infamous for the timing belt/chain/rope/thread going at 70K miles.
The joke was the light on the dash was a "Change Engine" light.
 

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Just thinking. In the past, when a belt or chain broke, the valves would slam into the pistons if the engine was an 'interference' engine.

I could only imagine what would happen if you're cruising along, in gear, and the electricals cut out. Electric boost to the steering goes to heck, and the engine valves on the intake side would all go to default position. Either open or closed. In either case, there is a chance the intake valves would slam against the pistons.

Whats wrong with my logic? Clearly Fiat thought of this. What truly happens? Any gearheads out there?
chains generally don't break...the guides will wear and make noise or maybe skip a tooth...chains will let you know when there is a problem...don't worry have fun....this motor is bulletproof....good luck
 

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chains generally don't break...the guides will wear and make noise or maybe skip a tooth...chains will let you know when there is a problem...don't worry have fun....this motor is bulletproof....good luck
This is, in my experience, correct. Only time I had to replace a timing chain, there was no mystery something was not right, and I got it fixed before it broke. IT was also ~22 years old by that point.

I'd be much more concerned about several other areas of the vehicle being the source of insurmountable repairs than the fact it is an interference design with a timing chain.
 
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