Help me estimate true odds of timing belt failure

[spark55155]

Shannow, you are incorrect when you say "most will fail in an average time." In fact, almost all timing belts will be in very good condition in an average time.

To be more precise, The “bell curve” absolutely does NOT describe the relationship between the age and mileage of a car and the likelihood of timing belt failure. If the bell curve described this, after some number of miles the chances of a timing belt failure would DECREASE with increasing mileage – but we KNOW this isn’t the case. The curve that describes the failure rate of timing belts approximates what is known as the “bathtub” curve, which is sort of the OPPOSITE of the bell curve. I hope you haven't been telling too many people about your "bell curve" theory!

 

[Bottom_Feeder]

Thanks for the warning, Doc Brown!

 

[JC1]

Originally Posted By: The Critic

Paying $500 now to ensure several more years of trouble-free operation is a no-brainer.


He's in Canada. When I called around a few years ago for a timing belt and water pump replacement for a 97 Civic the cheapest price I was quoted was around $450. Doing the other stuff is a lot more pricey in the Great White North. Plus we pay 13% taxes on top of that.

For instance when I replaced the 3 accessory belts for the 97 civic the price was around $60 from the local parts place.

He could probably drive the car until the belt brakes and replace the engine with a used Civic engine for around $1000 installed. Installing a new timing belt along with it. I know that'a a stupid approach, but some people might chance it.

Regards, JC.

 

[Anduril]

I've never understood this. What advantage, if any (besides hopefully getting the owner back to the dealer every so many miles to pay for replacement) is offered by a timing belt/interference engine design as opposed to a non-interference or chain design? From what I know, the answer is "none," and for that reason I did (and will continue to) only buy chain-equipped vehicles that do not need expensive changes or risk even more expensive engine damage.

 

[tc1446]

Originally Posted By: Anduril
I've never understood this. What advantage, if any (besides hopefully getting the owner back to the dealer every so many miles to pay for replacement) is offered by a timing belt/interference engine design as opposed to a non-interference or chain design? From what I know, the answer is "none," and for that reason I did (and will continue to) only buy chain-equipped vehicles that do not need expensive changes or risk even more expensive engine damage.


While timing chains are likely to outlast belts, they do indeed wear out. Had one installed not long ago in my 04 Corolla to the tune of $600. Mechanic was [censored] about thin chains now in use and showed me one he has just changed in his daughters Mazda (I think it was). Car had around 160K on it and chain had been ticking for some time. At least it did give some warning.

 

[Clevy]

Originally Posted By: demarpaint
I would change it when they recommend changing it, if I were to stretch the interval I would probably not go past another 20,000 miles. So it they call for a 60K change 80K would be the max.

The belt could last the life of the car or break at 60,001 miles. I don't like getting stranded, especially when the maint. intervals are clearly stated. JMO


I agree with this statement.
The interval is set so that catastrophic engine failure can be averted. The belt could very well last double the prescribed interval or it could fail before the scheduled change,you just can't know for sure.
I'd never buy a car with an engine that has a timing belt. Extra maintenance that can be avoided.
Take your chances if you want.

 

[hattaresguy]

Originally Posted By: Anduril
I've never understood this. What advantage, if any (besides hopefully getting the owner back to the dealer every so many miles to pay for replacement) is offered by a timing belt/interference engine design as opposed to a non-interference or chain design? From what I know, the answer is "none," and for that reason I did (and will continue to) only buy chain-equipped vehicles that do not need expensive changes or risk even more expensive engine damage.


Cheaper to build, and cheaper to make a quite engine.

Gears are the best but making a quite OHC V engine gear driven costs a fortune. But when money is no object...the 6.75L Rolls Royce V8 is gear driven. It takes 80 hours of hand fitting to get those gears to mesh so its as quite as a Lexus V8.

 

[y_p_w]

Originally Posted By: tc1446
Originally Posted By: Anduril
I've never understood this. What advantage, if any (besides hopefully getting the owner back to the dealer every so many miles to pay for replacement) is offered by a timing belt/interference engine design as opposed to a non-interference or chain design? From what I know, the answer is "none," and for that reason I did (and will continue to) only buy chain-equipped vehicles that do not need expensive changes or risk even more expensive engine damage.


While timing chains are likely to outlast belts, they do indeed wear out. Had one installed not long ago in my 04 Corolla to the tune of $600. Mechanic was [censored] about thin chains now in use and showed me one he has just changed in his daughters Mazda (I think it was). Car had around 160K on it and chain had been ticking for some time. At least it did give some warning.

They have to be lubricated too, and oil issues have resulted in timing chain failures or at least wear. Timing belts tend to fail quickly, but they're running great to that point. A chain could start slowly getting sloppy.

I do remember when Honda began to recommend 90K timing belts even when they previously spec'ed 60K. They were also a huge pain since they drove the water pump.

Which reminds me that it's almost been 10 years and over 100K miles on my WRX. I can't find the recommended intervals, but I thought it was recommended at 105K miles. I understand that Subaru timing belt changes are a lot easier.

 

[wirelessF]

Here is a true feat: Tundra V8 original timing belt at 262,000mi.

http://www.tundrasolutions.com/forums/1gen-tundra/252498-original-timing-belt-262-000-miles/

Belt is noticeably stretched which surprisingly there are no cracks or missing pieces in the belt.

 

[Cujet]

I've had 2 belts fail on me. Both times, the car simply stopped. No drama, no warning.

On the boss' Porsche 944, it was very expensive. On dad's Pontiac, it was a simple matter of installing the new belt.

Both failed within the specified replacement interval. And both times it was during steady state operation down the highway.

In each case the idler was also in need of replacement.

 

[Errtt]

I've had a few vehicles with timing belts. Still have one, 98 Camry I have my youngest drive full time. College kid.
I'll change as recommended rather than risk any borrowed time. Have never had one break.
Had a friend what was overdue on his car (eclipse). Said he would have it done after return from vacation as he'll have a few days free at home before returning work. It broke and stuck him & his wife while out of town on vacation. Have that happen on a fairly busy overpass between towns.