timing belts vs chains

Thought I'd ask here first, as this seems to be a very knowledgeable group.
What is the advantage of a timing belt, as opposed to a timing chain, in an automobile? The reason I ask is I just paid $583 for a set of new belts, timing belt and water pump for my 90 Maxima. The newer models have a chain which does not require this expensive maintenance (to my knowledge). Nissan did a good job with this car so I can't believe they just threw on a belt instead of a chain without a reason. So why?

Belts are cheaper to manufacture and they keep you going back to the dealer! My old 84 Porsche 944 timing/balance shaft belts usually run $1200, cause once you have it apart, you should replace the seals, tensioner and water pump. I'd prefer a timing chain that needs no maintenance.
Rob

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notos&w said:
Thought I'd ask here first, as this seems to be a very knowledgeable group.
What is the advantage of a timing belt, as opposed to a timing chain, in an automobile? The reason I ask is I just paid $583 for a set of new belts, timing belt and water pump for my 90 Maxima. The newer models have a chain which does not require this expensive maintenance (to my knowledge). Nissan did a good job with this car so I can't believe they just threw on a belt instead of a chain without a reason. So why?

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Belt advantages: lighter, quieter, cheaper to manufacture, *slight* efficiency improvement

Belt downside: PITA maintenance item, potential for significant engine damage when it breaks [for some engines]. Engine damage true with chains too but they rarely break.

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Doug S said: Engine damage true with chains too but they rarely break.

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About the only reason you see a real timing chain anymore on a lot of cars--dependable.
Last time I was looking at vehicles I asked about the chain vs. belt and most salespeople didn't know. I had to ask the mechanics.

-Jason

I believe many manufacturers still put timing chains on their larger (V6 and V8) engines. Its mostly on 4 cylinder engines that I see timing belts. A belt will have less rotating mass, and not rob as much power from the engine as a chain would. Things like that can be important on smaller 4 cylinder engines.

Out of our three cars (all four cylinders with timing belts), two are interference engines, one is not. That means if the timing belt breaks on either one of our Neons, valves will contact pistons, and major damage will result. It isn't really a big deal to me though. I change the timing belts myself, and they only cost $50-75, which isn't too bad to do once every 100,000 miles (6-7 years for us).

-Keith

A belt is pretty much a necessity on a overhead cam engine, the chain doesn't flex and bend around the curves as much. Chains last the lifetime of the engine so you don't have to pay 500-1500 every few years (or every couple years if you actually drive anywhere). A chain is less likely to fail than a belt which is why you have to replace the belt every so often. I try not to own an engine with a belt, I want the extra relaibility. They say the belt can last 60-80k miles, well they say the same about your fan belt or radiator hoses or tires (same kind of rubber) so I ask why do you carry a spare tire then? I replace my fan belt and rad hoses before 50k and stick the old ones somewhere under the hood incase the new ones were ever to break, I can swap the old one on for long enough to buy a replacement.

I beleive the factory chain in my Cherokee is rated at 300,000 miles before it needs to be changed.

Most motorcycles still use timing chains rather than belts, but in center of compact transverse 4, where would you put a belt...

Though Honda,in particular, went through a long period of chain and tensioner problems, tensioners that didn`t,loud rattling sounds, slack cam chains eating there way out of the side of the barrels.

Honda used the third way at one point, gear driven cams.

Some didn`t need servicing just go dealers for regular warranty modification.

I always reckon on about 36K for a belt, manufacturers say 60K, they also sell a reconditioned diesel cylinder head for £550 + VAT the one time I had to buy one...

Adam

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Eugene said:
I try not to own an engine with a belt, I want the extra relaibility. They say the belt can last 60-80k miles, well they say the same about your fan belt or radiator hoses or tires (same kind of rubber) so I ask why do you carry a spare tire then? I replace my fan belt and rad hoses before 50k and stick the old ones somewhere under the hood incase the new ones were ever to break, I can swap the old one on for long enough to buy a replacement.

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Timing belts (at least the ones I've seen) are definitely not made the same way as normal serpentine or V belts. Because of the requirements to last longer, as well as the possible catastrophic consequences (on an interference engine), they have to be made more durable than standard accessory belts. I've got 102,000 miles on my Dodge Neon. I changed the timing belt at 100k miles (factory recommended change interval is 105k miles). The belt was still in great condition, and I would have had no problem with using it for another 15-20k miles. I changed my two accessory belts (V belts) at 70-80k miles. Both still had a lot of life left in them.

Timing belt manufacturers recommend 50-60k belt change intervals because they want to sell you twice as many belts as you really need. Chrysler would not have specified a 105k mile timing belt change interval if belts were only going to last 60-80k miles.

I've still got the original radiator hoses on my Neon, the stock accessory belts were in good condition at 70-80k miles, and the timing belt was still in good shape at 100k miles. Did I mention the car is raced about two weekends a month, and isn't treated very gently the rest of the time? I think I've only had one timing belt break on a car in over 300,000 miles of driving cars equipped with timing belts, and that was on a used Volvo that was not an interference engine, and we just had it towed to a shop and had them replace the belt.

Belt and hose manufacturing has come a long way in the last 30 years. They are built a lot better than they used to be.

-Keith

My Renault 11 TC (4 cylinder 1237cc) has a chain. It's an old pushrod OHV engine, which means that I don't really have to worry about chainging a timing belt every five minutes. However, I've got a noisy tensioner! And getting to it to inspect the cause requires me to remove the water pump, alternator, half a dozen pipes from the air con, and drop the sump...not fun. Unless it gets noisier, it's getting ignored! Even if the chain did go, I've got a head complete with valves down the road anyway!

I'd certainly take a chain over a belt any day. Unfortunately, all of my favourite cars (apart from my Renault, which was bought as s stop-gap while I fixed the old Metro (Which also has a chain, despite being a 998cc 4 cylinder engine made in 1981) - however, I ended up liking the Renault that much that I've kept it). Lada have a belt on their 1300 and 1500 engines, not sure about the 1700i as I've never had a chance to poke around under the hood of the newer Nivas which were the only ones fitted with that engine. All the Saab 900's (Classic model anyway) had belts. Only car we've had a t-belt go on was our old FOrd Sierra 1.8. That took out the valves. The engine was shot anyway, so we just replaced the whole unit (£200 for a recon engine).

Timing? Maintenance? Hmmm. Quaint.

/ubbthreads/images/graemlins/grin.gif

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NeonLights said:
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Eugene said:
I try not to own an engine with a belt, I want the extra relaibility. They say the belt can last 60-80k miles, well they say the same about your fan belt or radiator hoses or tires (same kind of rubber) so I ask why do you carry a spare tire then? I replace my fan belt and rad hoses before 50k and stick the old ones somewhere under the hood incase the new ones were ever to break, I can swap the old one on for long enough to buy a replacement.

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Timing belts (at least the ones I've seen) are definitely not made the same way as normal serpentine or V belts. Because of the requirements to last longer, as well as the possible catastrophic consequences (on an interference engine), they have to be made more durable than standard accessory belts. I've got 102,000 miles on my Dodge Neon. I changed the timing belt at 100k miles (factory recommended change interval is 105k miles). The belt was still in great condition, and I would have had no problem with using it for another 15-20k miles. I changed my two accessory belts (V belts) at 70-80k miles. Both still had a lot of life left in them.

Timing belt manufacturers recommend 50-60k belt change intervals because they want to sell you twice as many belts as you really need. Chrysler would not have specified a 105k mile timing belt change interval if belts were only going to last 60-80k miles.

I've still got the original radiator hoses on my Neon, the stock accessory belts were in good condition at 70-80k miles, and the timing belt was still in good shape at 100k miles. Did I mention the car is raced about two weekends a month, and isn't treated very gently the rest of the time? I think I've only had one timing belt break on a car in over 300,000 miles of driving cars equipped with timing belts, and that was on a used Volvo that was not an interference engine, and we just had it towed to a shop and had them replace the belt.

Belt and hose manufacturing has come a long way in the last 30 years. They are built a lot better than they used to be.

-Keith

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I realize they are better now, but I like to be prepared and look at every potential. I also replaced my compact spare witha full size tire for that very same reason. I also carry a repair manual and tools, spare spark plugs and wires, bulbes and fuses. I guess its a habbit from early on when I moved away from my parents to go to college, I had no one close by to call for help if anything happened and had a truck that came from a repo auction and was raced. I run my vehicles hard and for many years (still have that old truck too) and use them for work and to haul crap when I need to so I have to be extra picky.

i must say every timeing belt i replaces was in great condition except a ford escort gt but the owner who had the car b4 didnt put the timeling belt cover on corect and it made a grove in belt.but i still replace em at arounfd 60k.just because i dont like being on the side of the road and sure dont want to replace a timeing belt on side of road

We've got a Volvo 850 that needs it's timing belt religiously changed every 70k. It's an inerference engine of the worst kind.

We purchased the car in January with about 96,000 miles and after debating it for a few months decited to just go ahead and have the belt changed ($400 is a whole lot cheaper than a $4000 engine job). Mechanic, who is 100% absolutely trustworthy, said belt was literally in shreds and ready to go any moment.

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Eugene said:

I realize they are better now, but I like to be prepared and look at every potential. I also replaced my compact spare witha full size tire for that very same reason. I also carry a repair manual and tools, spare spark plugs and wires, bulbes and fuses. I guess its a habbit from early on when I moved away from my parents to go to college, I had no one close by to call for help if anything happened and had a truck that came from a repo auction and was raced. I run my vehicles hard and for many years (still have that old truck too) and use them for work and to haul crap when I need to so I have to be extra picky.

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I agree with you about needing to be prepared. I keep a well stocked tool bag in all three of our cars, full size spares in two of them, and the third will soon follow, as well as necessary fluids, spare parts, etc. Although it is usually redundant, we also have a AAA+ membership, just in case.

-Keith

Yea, I have the fliuda snd stuff still in my old truck, my cap wouldn't quite fit the new one so I untill I sell my old truck I don't have a good place for spare fluids. I have helped more people than myself thouh. Junlstarted I don't know how many people, helped a person replace a battery whose terminal had snapped off and patched a radiator hose for a lady and her son in a rest area.

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Zelandeth said:
All the Saab 900's (Classic model anyway) had belts.

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Oddly enough, it's only the 6 cylinder Saab's that had timing belts, the 4's have always and still have timing chains.

V6 Saab...I still think that's an oxymoron.