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Why a Timimg Belt Instead of a Chain?

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belt chain instead timimg why
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11K views 67 replies 23 participants last post by  tjnielsen  
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#1 ·
Maybe this has been covered, but it seems that the timing belt on a 1.8T is a never-ending source of worry. In fact, almost every manufacturer now uses timing belts and have done so for a long time.

Time was when cars (my Dad's old Ford 390 V8, for example) had timing chains. Some people even replace these with gears. I never recall worries about replacing these chains, though they weren't roller chains. Is a chain really any better or does it really last any longer? Or, does a chain have roughly the same lifetime, but -- being internal -- harder to replace?
 
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#2 ·
I've always heard it's about reducing NVH above anything else.

Think about garage doors...chains are loudest, screws less so, and rubber belts are nearly silent.
 
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#4 ·
The belt is better for our finely tuned modern engines. OHC engines are popular now and chains would be really long causing additional problems, noise, and some loss of efficiency. (Of course that loss was kind of hard to notice in a big bore gas-guzzling V8 from back in the day. You might have a belt on the supercharger, but not for timing.) Those old chains were not maintenance free, either. They would gradually stretch and begin to wear and cause problems. Of course back then you could tweak the distributor and compensate a bit. Getting to one for maintenance was usually a nightmare, too. So chains did just tick along for years dropping slowly in performance as they aged. We'd often have to pull a chain and measure it for stretch. They were not cheap so they usually went right back in the engine if they were in spec. Now we mostly have timing belts which are smooth-running and better than chains but if they are neglected or snap it will bite your ass and your bank account and not think twice about it. Good riddance to chains in passenger cars, I say. True some cars were worry-free with a short chain, but nowadays we would not like them very much.
 
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#6 ·
Wow, this is more pro-belt commentary than I've heard in my entire life, all in one place. I had always heard 99% of people say chains were hands-down superior, although more costly and noisier.
 
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#9 ·
Wow, this is more pro-belt commentary than I've heard in my entire life, all in one place. I had always heard 99% of people say chains were hands-down superior, although more costly and noisier.

Just remembered VW is going back to chains - the 2.0 engine in the Audi is now chain drive .
 
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#11 ·
Modern chains aren't exactly designed for serviceability either. The 2.5L in the Jetta is chain too and it's between the engine and transmission so the transmission has to come out. Some Audi V6 and V8s were having chain problems and the chain is at the back of the engine. Replacement at the dealer is about $7000 to pull the engine and transmission and replace the chains, guides, fluids, reinstall, etc.

Belts are designed to be serviced.
 
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#12 ·
chittychittybangbang said:
Belts are designed to be serviced.
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Not exactly, especially on our Passat.

Why a timimg belt instead of a chain? Because it's cheaper to manufacture this way.

And chains also tend to "stretch" due to heat than belts? Very funny.

BMW and Mercedes Benz have been using timing chain for many years and they seldom have had any problems and the chain normally lasts the lifetime of the engine.

Toyota has switched to timing chain on all of their engines, I4, V6, and V8, the same on the Nissan. Honda is still using the timing belt on their V6 even though they switched to chain on their I4 since early 2000.

Using timing chain will be always better than timing belt for reliability and long life especially on interference engines. You will never know when the belt will fail, even if you have very low mileage but with older age. Chain will never deteriorate if you don't use it.
 
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#16 ·
I think belts got a bad rap, at least in the B5 Passat for two reasons. One, is the fact that the cost of replacement was so high due to needing to take apart the entire front end of the car to replace it. This really turned off customers to VW due to the overall cost to maintain the car. The second issue is that the belt is used in an interference engine. So when the belt broke, it meant that the top part of the engine needed major repair. I had an older Pontiac that had a 1.8 engine and a timing belt. The belt broke. The car left me by the side of the road. But after a new belt, I was on my way. No engine damage. I'd like to know more on why all the engines are interference. Could shaving some weight be that big a deal on the engine? I think in the end, the switch back to chains in the 2.0 was due to reduce the cost of ownership and bring more people back to vw that might have been turned off by the cost of belt replacement in the b5. Just my $.02
 
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#23 ·
gstrouse said:
I think belts got a bad rap, at least in the B5 Passat for two reasons. One, is the fact that the cost of replacement was so high due to needing to take apart the entire front end of the car to replace it. This really turned off customers to VW due to the overall cost to maintain the car.
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This is also not true, and a common misconception spread by those on this message board who advocate the complete removal of the nose (lock carrier) as opposed to standard "service position".

It takes less than 20 minutes to unbolt the nose and slide it forward per factory specs. There are no hoses or electrical disconnected. Unbolt and slide forward. Done.

Those who think they only have enough room to do the job with the nose completely off either:

A) Don't have the right tools.
B) Don't have the patience and/or skill to work on a car.
C) Have never worked on anything but a VW and for some reason think it's really difficult.
D) All of the above.
 
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#19 ·
One, is the fact that the cost of replacement was so high due to needing to take apart the entire front end of the car to replace it.

Yeah , a local Honda dealer has been running an add for months for a TB special - $389 including water pump and $ $75 more if the tensioner has to be replaced .
 
#20 ·
you do know that honda engines are transverse and ours aren't? That's the issue right there. a 2.slow timing belt change is fast, cheap and easy LIKE A HONDA
 
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#26 ·
Honda went to chains because too many complaints from owners about the need to replace a belt and all the associated horror stories from the service techs about the perils of neglecting this service = worried & upset owners.

With the new engines, most mfg have gone to chains as the tensioner designs have improved enough to negate the concerns about noise and engine oils have also improved addressing the wear issues.

IMHO, once the Passat is set up in service position, the actual belt job is pretty straightforward. I've done 3 TB jobs in my life, my 2004 Passat 1.8T will be done this summer and I am looking forward to the job, gathering all the stuff, educating myself, spinning wrenches in my sleep :0)
 
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#30 ·
What a bunch of baloney. Chains are less refined than belts? Chains can't be super-tight? Chains make a ton of noise because they slap around? Chains stretch more than belts when they get hot? Chains disintegrate if they lose lubrication?

If these are the case, then the real mistake VW made was not using a timing belt to drive the exhaust camshaft, but using a tensioned chain to link the exhaust camshaft to the intake camshaft. And yet, to date I don't think anyone has ever needed to replace their cam chain(s), though the tensioners do wear out sometimes, but it's almost always the gasket that maintains oil pressure instead of the tensioner itself. And as long as the chain can be dipped into a puddle of oil (pressurized spray is NOT necessary), it will stay lubricated just fine.

Engines that use timing chains routinely run for hundreds of thousands of miles without requiring chain/tensioner service. VW used a belt because it was a little bit lighter, a little bit easier to service, and most importantly it requires service that the owner gets to pay for.

It's a bit of a stretch (pardon the pun) to use this comparison, but racing road bikes use chains that don't even maintain perfectly-straight chainlines because of all the gears that the riders shift between, and they are still upwards of 95% efficient at transferring power to the wheels, some going as high as 98% efficient. Unrefined my arse.
 
#32 ·
Is this another candidate for the Black-Hole? Because it seems like it's headed there.
For those that are getting red-faced over this: If you don't like it, get rid of it.
For those that do not mind it: Make sure you replace it at the proper interval.

A timing belt was used to make engineering the engine simpler; having a chain or two driving the DOHC system driven by the main Cam would be difficult to engineer with the amount of space provided. It was easier to simply have one belt do the same work one or two chains would be doing, rather than engineer the engine around the chains. Many auto manufacturers use the belt as opposed to a chain, so don't hate on VW for it just because you like to.
 
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#35 ·
Passat2.8 said:
A timing belt was used to make engineering the engine simpler; having a chain or two driving the DOHC system driven by the main Cam would be difficult to engineer with the amount of space provided. It was easier to simply have one belt do the same work one or two chains would be doing, rather than engineer the engine around the chains. Many auto manufacturers use the belt as opposed to a chain, so don't hate on VW for it just because you like to.
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Uh, no. A timing chain would be less than half as wide as the timing belt, leaving more than enough room for the dust shroud that the chain would need since it would be actively lubricated. Meanwhile, there wouldn't need to be a cam chain or associated tensioner, which would free-up some space on the back of the engine, so the Hall sensor could be relocated back there where it would never be an issue since they almost never fail. Sorry kid, better luck next time.

Thanks for the reminder that I can always ditch the car at the drop of a hat, though -- I'd forgotten it was as easy as taking it to the junkyard and tossing them the keys. :whistle:
 
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#33 ·
I've done both a Honda B18C5 Timing belt and my Passat, time wise, it was a wash. Taking the front end apart is a thirty minute job after the first time, which is about as long as it to me to get around the right side motor mount on my B series. I like VW's system, I think it is simple and easy to change. It is a 3-4 hour job once you know what you are doing. If the service position is scaring you from doing a TB job, you don't need to be doing it in the first place.
 
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#34 ·
Holy cats! I raised more of a ruckus than I had imagined fo such a simple-sounding question.

It seems that both work well, and that both have their share of problems. But, it also seems that technology may be now leaning towards chains rather than belts. That's fine by me!
 
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#37 ·
I'm in the timing chain camp. I've owned 3 SAAB's, all with timing chains, all with over 300,000 KM and I've never had any issues with the chains. Agreed, the tensioners can fail. However the failure is gradual and unless you're either a) deaf or b) clueless, you can catch it before it goes. Not so with a timing belt. Also, VW's decision to use a timing belt with a timing chain on the back is just plain stupid. It's entirely unnessecary to have two links in the timing system.
 
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#43 ·
Mister T said:
Also, VW's decision to use a timing belt with a timing chain on the back is just plain stupid. It's entirely unnessecary to have two links in the timing system.
Click to expand...
The chain link between the two cams allows for adjustability in the non-belt-driven cam by changing the position of the chain. It's a very simple, and reliable, timing advancement system. I'm really only familiar with my V6 heads, but I'm sure the I4 uses a similar, if not identical, system.
 
#41 · (Edited)
I think that was very to subtle for me to post, not really showing much emotion in it other than being mature enough to state that he went beyond his boundaries and insulted me. Last time I was stated to have insulted someone it was much more in the direction deux was going here. I was insulted, therefore he broke forum policy, end of story. Besides he brought this thread back to attention by posting what he did, quite unnecessary. I am not angry, nor was I when I posted my reply, so he did not get the "reaction" he wanted. We can all be civilized here. And you state it as "insulted"; he labeled me as a kid, and the last time I checked kid's did not know how to properly navigate and steer a 17,000 long-ton ship, or any ship for that matter. This is an automotive forum, and it is not the place to hang around waiting for the right post to make insulting comments at, as per the rules and regulations of the forum.
 
#46 ·
Well I am sorry I don't have a few thousand posts here; I guess since I don't I'm to be told what offends me personally and I'll take all the stuff that is thrown at me and not say anything at all. I'm really curious as to how I'm the bad one in this case as I have been more than civilized, calm and non-insulting to anyone. I spoke my mind and am done here, if you don't like it ban me; I have a clear conscience.
 
#50 ·
Those systems just happen to be patented since they operate so well. When those systems came out they were run by belts; after they had learned that belts are less reliable they had went to chains. Hopefully VW will learn their lesson and do a complete switch over, so don't praise other manufacturers for using chains now when they originally used belts and were in the same predicament VW is in now. Some say it was because VW was cheap, here is some evidence for you: at least they were not cheap enough to not realize that a safety should be put in place to stop the car from accelerating into oblivion.

This thread is like the Monday morning quarterback; well they should have, could have, and would have; it can't be changed now so we have to just deal with it. Stop hating on VW because of it and be thankful the cars are not defective in any was that they will flip over and kill us (Lexus GX460) or accelerate into oblivion (Toyota/Lexus) or do any manner of what engineering disasters the automobile industry has created.

Also, my father owned a Saturn SL1, and at about 150,000 miles the timing chain was slapping around horribly and needed replacement; chains are not perfect, everything has it's flaws.

Just so people here don't assume I don't have my head up my you-know-what; here is a list of sites with compiled information:

p=2533163#post2533163
http://www.car-techie.com/timing-belt.php
http://www.crxsi.com/articles/read/what-s-best-timing-belt-or-timing-chain-february-2009.htm
http://www.saturnfans.com/forums/showthread.php?t=78717
http://www.alldeaf.com/auto-talk/66181-do-you-prefer-timing-chain-timing-belt.html
http://www.aa1car.com/library/2003/us70343.htm
http://www.nsxprime.com/FAQ/Maintenance/timing_belt.htm
http://www.underhoodservice.com/Art...s_chain_reactiontiming_chain_replacement_on_toyotax2019s_22r_series_engine.aspx

Do I need to keep going? Chains are not godly; both the chain and belt have their share of problems. Perhaps maybe this topic can be laid to rest, and people will quit blaming VW for using a belt.
 
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#57 ·
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