Just curious, which new cars still use a timing chain?

[eng2d2]

Yeah that's exactly the point where timing belts are an issue. My previous 94 Del Sol had 240k miles and still ran great, but needed a belt. I decided it wasn't worth dropping the cash into having a mechanic do it, so I learned myself. It wasn't bad actually, aside from getting the crank pulley bolt loose. The sucker was tight after not moving for almost 20 years. Bright side? Total job cost less than $80.

What was your labor hours including reading and watching video? Those are not free. I would only get cars with timing chains.

 

[XavierMace]

JLee can vouch for my mechanical ineptitude. I still managed to replace a timing belt on a IS300. If I can do it, I'm pretty confident anyone in this conversation could.

 

[Ken g6]

As a computer guy but not a car guy, I'm surprised the whole thing isn't computer-controlled solenoids yet.

 

[Yuriman]

What was your labor hours including reading and watching video? Those are not free. I would only get cars with timing chains.

At the time I was a poor college student. My time was worth almost nothing. If I owned a car with a belt now and I still didn't know how to do it, I'd probably have a shop do it instead. But not everyone is in the good financial position I'm now in.

As a computer guy but not a car guy, I'm surprised the whole thing isn't computer-controlled solenoids yet.

Companies have experimented with this, but it's neither cheaper, nor as reliable. You'll likely see it come to million dollar hypercars first, but it's not even ready for that.

 

[eng2d2]

JLee can vouch for my mechanical ineptitude. I still managed to replace a timing belt on a IS300. If I can do it, I'm pretty confident anyone in this conversation could.

Yes but how long? By yourself??

 

[XavierMace]

Yes but how long? By yourself??

It was pretty much an all day job.

 

[ondma]

Not to mention a place to do it.

 

[jlee]

You have to change the timing belt like 5 times for the half a million miles. Meanwhile, there's good chance motor with stock timing chain can hit half a million miles. All the newer Toyota engines use chain instead of belt. I would much rather have chain instead of belt. Belt vs chain might not matter much to you since you probably change the belt yourself but someone like me who's mechanically inept, it's expensive taking it to the dealer for timing belt change.

You're still going to need a few water pumps in there, which drastically cuts the cost difference you think exists.

What was your labor hours including reading and watching video? Those are not free. I would only get cars with timing chains.

If your time is worth enough that one day every eight years to replace a timing belt is a problem, you should have no difficulty dropping $700-1k to have a timing belt service done every eight years.

 

[frozentundra123456]

You're still going to need a few water pumps in there, which drastically cuts the cost difference you think exists.



If your time is worth enough that one day every eight years to replace a timing belt is a problem, you should have no difficulty dropping $700-1k to have a timing belt service done every eight years.

You might, but at least with a timing chain you can wait until the pump is actually leaking, and you know it needs to be replaced. You dont have the conundrum of spending 700 plus on an old car when you dont know if it really needs it. I have never kept a car close to 500k, but at least until 100k I have never had a water pump fail except for a ford escort that ate them every 30 or 40k. It actually seems that most manufacturers are now going back to chains, which I think is a good thing. I could more easily accept the extra maintenance required for a belt if they had some major functional advantage over a chain, but I dont know of any. Maybe they are a bit quieter??

Edit: I really think the idea of replacing the belt one's self is a rather unlikely scenario, even though some here have done it. You need tools, a good place to do it, and a fair amount of skill. Plus you are risking engine damage by having an inexperienced person do it. I have several friends with cars with belts, and none of them have ever tried it themselves.

 

[Yuriman]

For what it's worth, I replaced a belt in a parking lot in an afternoon having never done it before, and lacking most of the "right" tools. Took a 6ft piece of PVC on a breaker bar to get the crank pulley loose, that was easily the hardest part. When I did it, I hadn't ever done anything more complicated than a valve adjustment or replacing an axle.

I was actually off one tooth on the timing and had to pull it back apart, but once I'd figured it out, it took no time at all.

 

[NutBucket]

https://www.amazon.com/Powerbuilt-648796-Cranks-Pulley-Removal/dp/B0000TMLWQ

A godsend for those bolts!

 

[lsd]

You're still going to need a few water pumps in there, which drastically cuts the cost difference you think exists.



.

The last 3 cars I've owned all have timing chains and all have a water pump that sit in an area that did not require the removal of any timing components/covers. A water pump replacement shouldn't cost anywhere near what a timing belt replacement would cost and for a diy'er it would be a far less daunting task too.

 

[jlee]

You might, but at least with a timing chain you can wait until the pump is actually leaking, and you know it needs to be replaced. You dont have the conundrum of spending 700 plus on an old car when you dont know if it really needs it. I have never kept a car close to 500k, but at least until 100k I have never had a water pump fail except for a ford escort that ate them every 30 or 40k. It actually seems that most manufacturers are now going back to chains, which I think is a good thing. I could more easily accept the extra maintenance required for a belt if they had some major functional advantage over a chain, but I dont know of any. Maybe they are a bit quieter??

Edit: I really think the idea of replacing the belt one's self is a rather unlikely scenario, even though some here have done it. You need tools, a good place to do it, and a fair amount of skill. Plus you are risking engine damage by having an inexperienced person do it. I have several friends with cars with belts, and none of them have ever tried it themselves.

If you're only going to 100k you don't generally need to change a timing belt anyway.

 

[frozentundra123456]

If you're only going to 100k you don't generally need to change a timing belt anyway.

Well, I hadnt planned to stop at a 100k, but one car had a catastrophic transmission failure, one went to 130k, and a couple met untimely ends at the hands of my wife. One of these was an Escort, and the timing belt broke at about 60k, conveniently for Ford, right after it went out of warranty. It had the catastrophic transmission failure as well, and required I believe it was 2 additional water pumps before it died, and of course a new timing belt with each water pump replacement. (total of 3 replacements in less than 100k) One of the most awful cars reliability wise that I have ever had.

The only car I have had go well over 100k is a Civic with 13 years and 150k on the clock. That one I replaced the belt at 90k and it is due for another based on time, but not mileage.

Have to say I have not had really good luck reliability wise with cars until I started buying Japanese brands. They have all been very good.

 

[JCH13]

Belts:
+lighter (supports higher RPM redline)
+quieter
+less drag
+more robust (no oiling system needed)
+easily adjusted cam timing with new cam gears
+easily upgraded for built engines
+wear does not appreciably increase belt length
- potential catastrophic damage during failure (the one timing belt failure I witnessed was in an interference engine and everything was unharmed, cams tend to settle into the safest resting configuration)
-wear out more quickly
-high likelihood of failure if service interval is ignored

Chain:
+Nearly indefinitely life
+/- up-gradable in some engines
+generally fewer drive parts to service than belt drives
+generally cheaper than belt drives
-wear increases chain length (cam timing slowly moves away from optimum, offset by the use of VVT system potentially, might explain why OEMs are generally moving back to chain)
-louder
-more drag
-heavier
-relies on multiple oil channels (one to lube, one to tension) if there are any oiling system problems the chain is at risk of failing
-potential catastrophic damage during failure, more likely to cause damage because there will be pieces of metal in the oiling system, and I heard that a timing chain bunching up on a timing gear cases a hellacious amount of damage.

There are good technical reasons why belts have been used and continue to be used. There is a real convenience benefit (and maybe cost benefit) to using timing chain.

Take your pick, but one is not automatically better than the other for all situations... except for rotary engines, which have no timing belt, chain, or other nonsense. Clearly it is the superior engine.

Here is another problem though. I still have the Civic I mentioned above. I replaced the timing belt at around 90k. Now the car is 13 years old and has 150k. Do I spend *another* 700 bucks to replace the belt on a car that is only worth maybe 3 or 4 thousand dollars. It still runs and drives perfect, but it seems stupid to spend 20% of the value of the car on a "maintainence" item. OTOH, it is an interference engine, and I dont want to trash the car, since it still runs very well and my wife likes it. And believe me, I have neither the skill or facilities to replace it myself.

Trade it in on a new car, lose way more than $700 in depreciation, increased registration/insurance costs, and sales tax (if applicable), you'll definitely come out ahead!

You'll pay or you'll pay... simply the cost of owning a car. Usually repairing is less expensive than buying a new/newer car when the TCO is considered.

 

[NutBucket]

Great post JCH.

There's always an exception, right? So when Honda designed the F20C for the S2000 they used a chain. And as we all know, it has a 9k redline...and I believe every other Honda 4-cylinder to that point used a belt. Of course, the K20 came out shortly after with a chain too.

 

[JCH13]

Great post JCH.

There's always an exception, right? So when Honda designed the F20C for the S2000 they used a chain. And as we all know, it has a 9k redline...and I believe every other Honda 4-cylinder to that point used a belt. Of course, the K20 came out shortly after with a chain too.

Thanks. Always an exception to every generality!

The super-high-50k-foot view is that the exact decision does not matter nearly so much as the implementation details of that choice.

 

[darkswordsman17]

As a computer guy but not a car guy, I'm surprised the whole thing isn't computer-controlled solenoids yet.

There have been attempts to do so (think most companies probably have an R&D vehicle that has an engine with them), with the most recent being Koenigsegg's "Freevalve" (they actually spun it off into its own company, and I think its been working to become a supplier), but from what I recall the cost alone makes it a non-starter for most companies (I think the sensors alone are more expensive than the whole valvetrain of most cars). I believe there is a Chinese company that's supposed to be producing an engine that utilizes it, but I don't know if it came out yet and if so if it is any good.

Fiat also has a system but its not quite the same. It actually is in production though (called Multi-Air). When the FCA merger happened Fiat talked about developing/integrating Multi-Air onto all the Chrylser engines (and talked it up as being great for the Hemi), but I don't think that materialized for probably plenty of good reasons.