Why I don't like timing belts ...

I've broken lots of timing belts but never a chain. Why do auto manufacturers use belts at all? To save a few ounces on weight? To ensure that the dealers will have a steady supply of service customers?

 

In the early days of belts they were touted as being quieter, but I think that modern chains are not nearly as noisy as the ones of 30 plus years ago. Most engines designed in the last 10 years or so have chains, the 2AZ-FE in my Toyota being a case in point. I too would be reluctant to buy any car that had a belt-driven camshaft.

 

Spot on mate, chains used to be a lot louder than belts 20 yrs ago.

Most, if not all manufacturers are heading away from belts now as you mentioned. Which is a good thing.

Ive only ever replaced a few worn timing chains in my lifetime, but still change many cam belts at 100K.

 

Belts are fine in non-interference heads.

 

chains noisy? nah they are just one more instrument in the orchestra

 

+1!

 

A Dino or Alfa timing chain "rattle" is music to my ears!

 

Music to everyone's ears I reckon!

 

The Chain on my 1993 Toyota pickup broke when the engine only had 155,000 miles on it ( i bought it new) . There is a thread floating 'round the fourm about a Lamborghini that broke a chain at only 90,000 miles.

 

Interesting!!!

 

Agreed. Much less of a problem in non-interference heads, but you're still immobilized and in need of a tow.

 

Yes it was the tensioner that failed first i believe. Stopped for gas just before it happened and heard a knocking sound but thought it was just bad gas or something, then it failed at 70 mph going up a hill on the interstate. I think the knocking noise was the failed tensioner banging round inside the belt cover.

 

And easier before it breaks and you have to reset the timing. Not real hard but still. Coming up on my second belt change in our Volvo did it @ 80k and turned 171k last week.

 

That sticker is worthless. W/O a receipt or a pic cd documenting the work that sticker means nothing. Just see your first post

 

I never had a chain break but I had one stretch so bad it wore a hole in the timing cover on a Jeep 4.0 straight six with 250K mi. Replaced the chain and sprokets used a little JB Weld on the cover and was good to go in an afternoon. Gotta love the old AMC 6. It lasted another 20k and was going strong when a semi ended the Jeeps life (and almost mine)

 

Belts have less mass and bulk, so maybe easier to design a high revving, more compact engine with belts? Chains are better for maintenance.

 

You have to watch some chains, as the gear teeth are covered in plastic to reduce noise. The plastic breaks and next thing you know you have pieces in the oil pan. All too common problem on Chevy V8's.

 

When I was working at the dealership in Denver I saw a Enzo break its chain before it hit 10k miles. Luckily for the owner it was still under warranty.

 

I can only wonder what all was damaged due to that.It would be interesting to know if the owner got a brand new engine or if they fixed it.Wonder what the cost would have been if it was not in warranty!

 

The sticker is meaningless unless it comes with records showing every part that touches the belt was also changed.
I was recently helping a friend with a Porsche that had bent valves. Belt was changed less than 6 months / 2,000 miles ago. One of the belt rollers locked up, which was never changed.

I'm working on a Mercedes with bent valves - this engine has a double timing chain.

My friends ZO6 also bent most of it's valves to due a failed chain.

 

Measuring wear (stretch) on a belt is possible but impractical. A visual inspection can give you a good idea of a belt's health.
Not only do t-belts themselves require more frequent servicing but they necessitate an additional oil seal at the cam and in engines where the water pump is driven by the t-belt a simple water pump bearing failure can destroy an interference engine.

 

Be patient all.....

We may not be too far away from electronically-triggered, pneumatically-actuated valves --- which means the end of camshafts and anything needed to drive them

A former classmate of mine heads up a group in Engine R&D for Ford, and he tells me they (and several other automakers) are making good progress on implementing such a design right now