This is going to a stupid question but I'll ask anyway. Does the MINI have a timing belt or a timing chain. If it has a belt, does that mean if it were to break the valves would be destroyed?

 

The 1.6L TRITEC engine (Both normal aspirated & Supercharged versions) use a timing metal chain instead of the more costumary rubber timing belt found in smaller 4 cyl engines (Specially from Asian makes).

This is yeat another reason why the 1.6L Brazilian built TRITEC MINI engine (BMW-Daimler Chrysler joint venture) is such a terrific, simple engineered and well designed engine. The timing metal chain means increased durability and virtually no need for the costly replacement of a rubber timing belt when the engine nears 60K, 90K or even 100K miles.

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2002 MINI Cooper CVT (Pepper White/Black Roof)
2001 Chevy Impala LS (For Sale)

On Order: 2004 MCS (Chili Red/White roof) September '03 production date, October '03 delivery.

 

yellowdesmo...Cooper4us is right. Surprising isn't it? It was a good question...I couldn't believe my ears when I found out it had a chain either.

 

I think I have heard that, although timing chains are not likely to ever break, they do eventually stretch, necessitating some form of service. Anyone know if this is correct?

 

Yes, stretching is an issue. Also if the chain tensoner fails it's just like having a timing belt failure. The V8 Ford Tarus SHO's engine has a nasty habit of it's timing chain jumping the cam sprokets requiring very extensive repairs.

 

Well,
That makes me very happy. Just one more reason to love my MINI that much more. I never really could understand why most import cars use a rubber timing belt.

 

You also asked about what could happen if a timing belt were to fail. Sometimes, nothing disastrous happens. It all depends on whether the engine has enough clearance to prevent the pistons from smashing into the valves if the cam stops turning. Some do, most don't.

When such a collision occurs, it usually results in bent or broken valves, and sometimes even a shattered piston. What would have been a couple hundred dollar job to replace the timing belt now becomes a major repair expense. At the very least, the cylinder head will have to be removed so the damaged valves can be replaced. If the head has additional damage (like damaged seats, guides or combustion chambers), further head repairs or replacement will be necessary. And if an open valve took out a piston? An overhaul or engine replacement may be required.

 

You also asked about what could happen if a timing belt were to fail. Sometimes, nothing disastrous happens. It all depends on whether the engine has enough clearance to prevent the pistons from smashing into the valves if the cam stops turning. Some do, most don't.

When such a collision occurs, it usually results in bent or broken valves, and sometimes even a shattered piston. What would have been a couple hundred dollar job to replace the timing belt now becomes a major repair expense. At the very least, the cylinder head will have to be removed so the damaged valves can be replaced. If the head has additional damage (like damaged seats, guides or combustion chambers), further head repairs or replacement will be necessary. And if an open valve took out a piston? An overhaul or engine replacement may be required.

 

Yes, I must say that I was relieved, and felt a bit more secure knowing it was a chain and not a belt.
My buddy girlfriend's Integra just got done in, due to that. She didn't know. If you catch it right away, then there's a good possibility of saving a major repair bill. But you'd have to shut her down pretty quick, otherwise that engine is going to be a hurtin' unit.
Cheers,

 

For example some older Hondas required the timing belt to be replaced between 40K and 60K miles. I think the replacement frequency has been increased to 90K+ miles on current cars.

The 3800 Series II V6 engine (200HP, Pushrod) in my Impala LS also uses a metal timing chain.

 

yellowdesmo: Timing belts substantially reduce engine noise, the belt and associated sprokets/tensioners are much lighter and lower in friction for improved power and they are much less expensive.

When a belt is used, the entire front engine cover can be made of thin plastic and needs no gaskets, seals, or even a proper fit. There is also no lubrication needed for any component -- relieving the oil pump and eliminating some manufacturing complexity. Furthermore, rather than a heavy, expensive cam sproket that has been precisely machined for a solid piece of steel, a belt system can use a sproket that has been stamped from sheet metal. So other than the replacement need and it's associated danger, the belt system is vastly superior in every way - more power, less noise, lower weight and lower cost.

I'll take a chain anyday though. :smile:

 

Ummm -- hadn't thought about this aspect when I bought my MINI or I might have had second thoughts (no way back now, though -- I'm keepin' 'er!).

I've had two engines fail in this component (one of them twice). In one instance, my '76 Chevette busted its timing belt while I was stopped at a light. It just died and that was it. Replacement cost me about $100 at the time. The second belt failed a week later 'cuz they'd either put in the wrong belt or set it up incorrectly. No big deal except for the hassle.

In the other case, the timing chain failed on my '72 Celica. The engine was LUNCH. It happened in a heartbeat and that was all she wrote for that car. As you might imagine, this experience made me a little gun shy about engines with timing chains. I'm banking on the fact that timing chain technology has improved somewhat in the ensuing 30 years . . .