Originally Posted By: Hokiefyd
Originally Posted By: CrackyWainwright
What do you gentlemen know about this? Thanks.
Both timing chains and timing belts offer individual benefits. The fact that both are used today is evidence of this. Having grown up on timing chains, I always had a preference for them. But, after changing the timing belt on our 2005 MDX and finding the job to be a breeze, I've sort of changed my tune.
A timing chain is usually designed as a non-serviceable system. Sure, you CAN fix it if it breaks. And some manufacturers have had to go into warranted engines to replace a chain on a poorly-designed system. But they're generally regarded as "for the life of the engine" systems. If it really lasts that long, then that's great. They sometimes don't, and my batting average is about 50/50 here. I've had excellent modern timing chain systems (Cadillac Northstar) and I've had some poor ones, too (Nissan KA24E). Various manufacturers have had some trouble with timing chains over the past few years, so they're certainly not a sure thing. They're not always done right. Unfortunately, nobody seems to know this until years down the road. They are becoming more popular as engine bays are becoming tighter -- a chain is usually a more compact design. Both from the spatial standpoint (it's physically thinner than a belt) and from the access standpoint (you don't have to provide clearance). This often means that a chain failure is not a DIY job, and sometimes requires pulling the engine to repair. They're also gaining popularity because of their low ownership cost. Chains have pros and cons.
So do belts. The are a designated "wear" or "service" item, which means that they should not be a determining factor in the life of the engine or vehicle. Like tires or brakes. You can buy OEM timing belt parts for a few hundred bucks, replace them on a sunny Saturday morning of your choosing, and you're good to go for another 100,000 miles. I like that they don't require any support from the lubrication system, and that they don't degrade the oil like chains can. I like that they're a DIY item, even if some choose to not go that route. I can only speak for why I like them, and that's an aspect that I like -- I can service it myself. A timing belt's only real downfall, in my opinion, is that it needs to be changed. For a DIYer, that becomes a non-issue, at least for a Honda V-6, which is pretty easy to do. For someone who can't or won't do it themselves, then, yes, that's a cost that needs to be recognized.
Here's a thread of mine about doing the belt on our 2005 MDX. I look forward to doing the belt on my '09 Ridgeline this spring.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2985744
I sometimes draw an analogy to valvetrain systems. Timing chains are like hydraulic valve lifters. Both are designed to be maintenance-free for the life of the engine, requiring no attention from the owner. Timing belts are like solid lifters with manual lash adjusters. Both are maintenance items that need to be addressed.
Chains, like hydraulic lifters, are great if they don't fail. If they fail or get noisy, they often require a tremendous amount of effort to replace because they're not designed to be serviced. Belts, like manual lash adjusters, require that periodic attention. But, because they do require that periodic attention, access for servicing is generally much easier. Keeping an engine running by servicing it and tuning it is a favorite past-time of mine. Newer systems that take me out of the picture, as a DIYer, generally have less appeal to me.
That's a great response. Thanks for the details. I wish I had the tools, knowledge, and patience to do work beyond oil changes here at home; I could have saved $10,000 over the last 10 years if I could do mechanic work myself. Having so few independent shops in rural Alabama, I have had to resort to dealership service departments WAY too often.