You are correct timing chains last damn near forever they can still break but it doesn't happen as often. Most if not all nissans cars have timing chains (Gotta thank nissan for that). And no you can't instal a timing chain on your neon it would take a lot of time, modifcation, lots of money.

 

My altimas have tensioners that don't have any rubber Although they tend to be noisey, but I would take my loud timing chain over a belt anyday seen to many belts break and cause way to much damage. Most timing chain driven engines allow for freewheeling valvetrain which means if the chain breaks your not ****ed. I am not totally sure if the engine in my altima does allow for that or not, a couple people have had them break with no damage but I know of one person that had to get a couple new valves. There always has to be an exception to the rule.

 

Yeah, I meant faced with servicing a timing chain or replacing a belt, I'd take the belt. The example of a friction tensioner was '30s era technology used by Nissan/Datsun and others into the '70s. I agree that timing chain technology has done pretty well in keeping pace with the increases in engine service life. But even Nissan's robust KA24 engine had a reputation for having timing chain guides replaced on the way to 200+K miles.

Belt vs chain and interference vs freewheeling are really separate issues. If our Neons were freewheeling, a busted belt would not be that big a deal..... especially since it probably should have been changed already anyway. The belt/interference combo is a result of manufacturers trying to optimize price/performance. Isn't the reason "most timing chain driven engines allow for freewheeling valvetrain" due to the fact that they are generally older or more conservative engine designs?

There are cases where I'd prefer a chain, too. All else being equal, I'd take a 90K mile car with a chain vs one with an original belt. Also, since age does matter to belts, I'd prefer a chain on a vehicle that I was planning to keep for many years but drive infrequently.

Both consumers and manufacturers will be better off when timing belt life is extended beyond 160K miles. I heard a rumor that even Toyota has a growing awarness that problems caused by deferred maintenance (timing belts, etc.) are affecting their reputation versus Nissan in the US market - though their preliminary conclusion was that Nissan owers just take better care of their cars [sm=smiley20.gif].

 

Yeah pretty much.

I like that conclusion!