Timing belts are a part we love to hate. They put a very real deadline on the life of your engine unless you spend many hours changing the timing belt; fail to do that in time and your machine is likely dead. But if you thought regular timing belts were bad, you haven’t met the disastrous technology of wet timing belts. They’re the ire of Europe, in particular, and they’ve won many enemies over the last two decades.
I’d never heard of wet timing belts until I came across this video on YouTube. What I found shocked me. The concept is simple enough: just build an engine where the crank pulley for the timing belt is actually in the oil bath of the sump. It’ll get nicely lubricated and run smoother and quieter, with a minor improvement to efficiency, which everybody loves. All good, right?
Well, reality has proven that’s not always the case. Wet belts have become a bugbear for many owners and mechanics. It’s one of those cases where many wish automotive companies had just stuck with the old way of doing things. They’re not just as bad as traditional timing belts—they may, in fact, be even worse. All thanks to one unexpected failure mode that can really ruin your day.
Why Use A Wet Belt?
The wet timing belt promised multiple benefits over a traditional dry timing belt. Lubrication from the engine oil was supposed to reduce wear and noise. More importantly, though, it reduced friction, which would provide an efficiency benefit, with fuel savings of around 1%.
The first mainstream engine that boasted a wet timing belt was the Ford 1.8-liter TDCI turbodiesel, as seen in the Ford Mondeo and Transit Connect. The original version of the engine used a timing chain from the crank to the diesel injection pump, and then a regular dry timing belt from the injection pump up to the cams. However, in 2007, Ford changed all that, using a wet timing belt to replace the timing chain. Traditionally, automakers had recommended that timing belts should never come into contact with oil, as it would degrade the rubber of the belt. However, these belts were manufactured out of special Hydrogenated Nitrile Butadiene Rubber (HNBR) that was more resistant to heat and oil, and also coated with Teflon for added resistance.
By design, the lower timing belt would come into contact with oil at the bottom of the engine. The wet lower belt was supposed to actually last longer than the upper dry timing belt, since it had the benefit of lubrication. Ford quoted a 100,000 mile, 5 year change interval for the dry belt, and a 150,000 mile, 10 year interval for the wet one.
The design quickly spread from there. In 2012, a wet timing belt made its debut on Ford’s 1-liter 3-cylinder EcoBoost engine. Renault also got on board, as did Volkswagen, Peugeot, Vauxhall and Opel. In the vast majority of cases, the wet timing belts were used on small displacement engines of 1.5 liters or less. Almost all are inline-three or inline-four engines.
Why Many Don’t Like Wet Timing Belts
First off, just google “Wet Timing Belt” and you’ll come across lots of stuff like this:
Yes, while there are plenty of examples of wet timing belts working just fine, despite the promised benefits, public opinion on wet belts is largely negative. You won’t find too many people singing their praises, but you can find a lot of gearheads raging against them. The reasons are simple. People are finding that they don’t last as long as promised, and they also introduce a significant additional problem that traditional rubber timing belts never had. We’ll get to that in a moment.
As you probably already know, a timing belt (whether wet or dry) syncs valve movement with piston movement and makes sure the valves are retracted from the combustion chambers as the pistons reach the tops of their strokes to prevent the pistons from colliding with the valves. If the timing belt fails on an “interference engine,” the engine will often die a very complete death as the pistons and valves collide. And so, it’s always wise to follow the manufacturer’s suggested interval for timing belt replacement and thus avoid the costly broken-belt scenario.
The problem is wet belts sometimes fail quite early. Why? Based on what I’ve found around the web, it seems the special compounds and coatings that make the belts more oil-resistant are not actually perfect. In many cases, they’re simply not able to keep a belt alive as long as automakers might have hoped. Sitting in hot oil just isn’t good for belt life, there’s no two ways about it. Using the wrong grade of engine oil or skipping oil changes can also potentially harm belt life. Contaminants in the oil and buildup of acidic content over time could make a difference, here.
This Peugeot engine had a wet timing belt rated for 112,000 miles or 10 years. This belt was looking ragged after just 75,000 miles and 6.5 years in operation.
Replacement is a sizeable job.
Wet belt engines are typically found in small European market vehicles, so dealing with wet belts has become a common problem for European mechanics. These vehicles have also been sold elsewhere, but much of the content discussing wet belt problems comes from Europe and the UK.
For example, it’s easy to find videos on the early Ford TDCI engines from British YouTubers, like this replacement video from mechanic Alan Howatt. “I know a lot of ya have had your engines trashed because these belts have failed,” says Alan. He’s eager to sound the alarm for Mondeo and Transit Connect owners. “I would seriously look into it and have it replaced if it needs doing,” he warns.
More Ways To Die
Even if a belt doesn’t fail, it can harm the engine in other ways. For example, if the timing belt starts coming apart and shedding particles, these can end up blocking the oil pickup, starving the engine of lubrication. This can kill an engine even if the timing belt is still largely intact.
Make no mistake: This failure mode is entirely unique to wet timing belts. This never happened with traditional timing belts because they exist completely outside of the engine’s oil system. It’s a special and terrible feature of the wet belt design. You can find mechanics decrying this problem all over the place.
Yes, it’s really that bad. You don’t just have to worry about your timing belt snapping. You also have to worry about it shedding gunk and cutting off your engine’s oil supply. Instead of just one ugly failure mode, wet timing belts give you two! How lovely.
What Is To Be Done?
Knowing whether your wet timing belt is failing is key to avoiding major engine damage. However, it can be difficult to determine. A visual inspection, if possible, is a good start—if swelling or cracking is apparent, the belt should probably be changed. For Peugeot, Citroen, Vauxhall, and Opel models, a tool is commonly available for checking belts—it’s a simple width gauge. If the timing belt doesn’t fit in the gauge, it’s swollen enough that replacement is indicated.
The belt can be checked in-situ in some engines by inserting the tool through the oil cap.
Beyond that, it’s worthwhile looking in the sump if possible to make sure the engine oil pickup isn’t fouled. Simply changing the oil won’t solve this problem. The debris must be removed from the sump and pickup if present.
It’s difficult to understand why these belt designs even entered production. The benefits seem relatively minor, and the risks seem almost obvious. For my money, as an engineer, I’d speculate that the problems with these wet belts weren’t obvious in manufacturer testing. Automakers might put millions of miles on mule vehicles, but they don’t test a new engine design for five or ten years prior to release. They test on accelerated schedules. There are ways to simulate longer-term degradation and wear, but they’re not perfect. I can only guess that the belts seemed fine, only to start falling apart and causing grander problems when they got out into the real world.
Thankfully, these wet timing belts aren’t everywhere. Japanese automakers largely haven’t touched them, and vehicles with bigger engines have mostly stuck with traditional timing chains or dry belt designs, too. If you do have an engine with a wet timing belt, though, you really need to stay on top of things. Keep doing your oil changes on time, and inspect your timing belt regularly—well ahead of the manufacturer-recommended interval. If it needs changing, change it, and check your oil pickup, too.
It’s just another one of the weird ways automakers have changed vehicles, and not for the better. This happens from time to time, but usually, lessons are learned and things get better again. Here’s hoping wet belts go the way of the PowerShift transmission and cease darkening our engine bays forever more.
Image credits: Alan Howatt via YouTube screenshot, driving 4 answers via YouTube screenshot, Ford
It’s telling to see the wet belt inspection tools/procedures. I was told early on in car ownership that you never, neverneverEVER “inspect” a timing belt, because the part itself is so cheap, the changeover itself so easy but so hard to get to that by the time you’ve already moved everything out of the way so you can take the cover off, and done that, and you’re already committed to putting it all back you’ve done 98% of the work involved in changing one and might as well make the change and reset the worrymeter to zero.
Depends on the car. On my Accord I can pop off the valve cover on about 10 minutes and inspect the timing belt(it’s not a wet belt but it is under part of the valve cover). Replacing the belt requires some pretty major disassembly of the motor mount, wheel well, and accessory drive. At least a couple hours job.
So I wouldn’t say “never never never ever” about something that is only sometimes applicable.
Yeah… a lot of Volvos have a plastic cover over the timing belt that takes two seconds to remove, so this is not accurate.
With the exception of maybe a few very rare cases, none of what you were told is true.
Despite Lewin’s assertion that wet belts are primarily used on small three cylinder European cars, wet belts are alive and well in large American vehicles. Just not wet TIMING belts.
Ford currently uses wet oil pump drive belts on just about every engine they make, and GM uses a wet oil pump drive belt on the 3.0 Duramax. And an oil pump drive belt breaking will kill your engine even deader than a broken timing belt will.
Many of these engines are in fullsize pickups and SUVs, many costing $70k or more, and many of them nominally intended for long term high stress work. I mean, some are even diesel.
That’s truly evil.
Why does the 3800 engine have a reputation for durability?
Cam-in-block, with a short timing chain between the crank and the cam. No tensioners, no followers, but yeah it’s “wet”.
And on top of that, it’s NOT an interference engine.
Not really sure why the 3800 engine has a special reputation for durability, since all of the attributes which allegedly make it special(like the pushrod valvetrain) are shared with most of its contemporaries. Ford and Dodge transverse V6s in the 80s, 90s, and 2000s also use a highly dependable pushrod valvetrain.
Running 250mph straightaway speeds at Indy may have had some effect on their reputation.
The 1.0 Ecotec motor also has a second wet belt that is moving the Balance shaft. It appears in many cases they never get replaced, even while the main belt might get swapped. But with the class action lawsuit against those motors, it would seem that few make it to the point of needing replacement of the belt.
But GM should take note, this is the sole reason why I would never buy a 3.0 Diesel Silverado. the oil pump belt being wet is just a stupid design, but add in the location behind the engine and an engine out belt replacement is just bonkers to me.
Dry belts used to be easy, on A1 platform VWs it was a non-interference engine, with good belt access and you just needed wrenches and a tensioner tool.
Wet belts and low tension rings are chasing marginal gains at high cost
This definitely seems like one of those mileage vs time things where replacement intervals are by mileage, but should be more by time or a “3 years/150k miles, whichever comes first” kind of thing. And what is the point of the difference in intervals between the wet and dry even if it theoretically works out? To replace the wet belt, it looks like the dry belt still has to be removed, so one might as well replace it while they’re in there, even though it’s only 1/2 through its lifespan. Or, more intelligently so you’re not paying all that labor twice in 50k to get to that point in the first place, you do them all at 100k and not bother again until 200k. Unless that dry belt is an easy job with minimal labor (looks easy in the photo, but that engine is not in a vehicle and it’s pretty stripped down, so that doesn’t mean anything), it would be cheaper over the long term and offer better peace of mind to do them all at 100k, which is what Ford should have just specced. Really, though, it’s a terrible idea that shouldn’t exist and I wouldn’t buy a car with an engine that had one.
Funny thing about that 1.0 Ecoboom. Against the N/A 2.0 it could optionally replace in the Focus, you got a more expensive engine with a large failure issue (on top of just being higher stressed in the first place), a lot less hp (though some more torque over a broader range) and, in the real world tended to not even get much better mileage. Then they had all those problems with the DCT that came from a dry clutch when they could have gone with a wet clutch . . . oh, Ford, you were so close. Did someone mix up the subjects at a meeting?
That is exactly why every belt, wet or otherwise, does in fact spec the replacement interval in miles and years, whichever comes first.
Why am I picturing a bomb with a lit fuse while hearing the Mission Impossible theme?
Eric @ IDoCars on youtube did a few about web belts.. you know what is more stupid than wet belts? Put the wet belt in an inaccessible location eg against the transmission eg GM Duramax I6.
Granted plastic chain guides are just as bad, but at least the drivers should notice slapping chains.
The 3.0L Duramax is the first engine that I thought of when I saw the headline “wet belt”. That one just had it’s service interval increased to 200,000 miles, and while I am not on any small Duramax forums, I’ve not heard of them being problematic. I would bet that pulling off all the equipment on the front of one of those engines would be as much labor and pulling back the transmission and transfer case on a longitudinal engined, RWD-based pickup truck.
I think the 200k miles applies to the latest revised i6.. who knows what they have changed to warrant the extra intervals.
I learned of this design just this year. My son has a Citroën C4 Cactus that he carefully maintains. He also deals with a trusted independent repair shop that has serviced his vehicles for the last few years. When the car was in the shop for some brake work around 75,000 km, the owner said that the timing belt should really be replaced because he had seen so many failures. Sure enough, the belt had started to crack. They also dropped the sump to check the oil pickup, which was clean, thankfully.
Ford uses them now in their current iterations of the 5.0 and 2.7 EB so it’s spreading. I can’t find much mention of trouble so far other than a random netizen claiming they’re superior because they can take more peak horsepower. (ignoring the long-term wear question)
I read something about a specific oil being required but that it might not be available in North America.
Anyways, it goes down in my book as “yet another sneaky landmine a buyer shouldn’t have to know about when buying a car” in the auto industry alongside Hyundai/Kia quietly skimping on immobilizers, etc.
Now if those belts were reasonably easy to replace and with realistic replacement intervals that one can depend on, I’d be more forgiving.
Order of preference:
Yes, especially numbers 8 & 9. In the late ’60s through ’70s, and I believe into the ’80s, some GM V8s, and perhaps some of their other engines too, used Cloyes-type timing chains (aka silent, link belt, or non-roller chain). To make sure it was a really bad design, the cam sprocket was aluminum with nylon gear teeth. Many engines would skip timing because the nylon teeth wore and disintegrated. Burnt paint on the center of the hood was an indication of a backfire through the carb and subsequent carb fire.
My ’78 Cougar had the plastic cam gear that was molded over a metal sprocket. I thought it was knocking even though the timing was right and the engine was only ~8.2:1 compression. It turns out what I was hearing was the timing chain slapping the inside of the timing cover because all the plastic teeth had broken off and the timing chain was only loosely being driven by the underlying (and quickly wearing) sheetmetal sprocket.
As it turns out, in typical 70’s GM fashion, they did one worse – they did the plastic cam gear thing, but omitted the sheet metal sprocket core, so when they (inevitably) sheared the plastic teeth off the cam gear, the cam just stopped instantly and you ran pistons into valves. This was an especially prevalent failure on the odd-fire Buick V6 of that era.
Plastic has no business being used in critical internal parts on an engine. The siren song is strong – they’re cheap and light and won’t rust and etc. etc., but the reality is that the (necessarily) accelerated durability tests that manufacturers use to qualify their products don’t catch the weird, slow degradation chemistry that seems to happen to most plastics in one form or another. Some plastics when exposed to infrared radiation (like the sort of thing that is emitted by, I don’t know, our sun, for instance) for long enough (~years) just… cease being plastic anymore and return to the monomer dust form that they were originally, independent of how they may have been mechanically loaded during use. Same thing if they’re exposed to low concentrations of things like ozone over extended periods.
The reality is that there is no way to accelerate these mechanisms, so manufacturers just Don’t Know if there is a failure mechanism lurking out there that will make a new material fail in some novel way when put into a new service / environment. But plenty of them have enough hubris to *think* they know all possible failure mechanisms and that their processes have all of them covered, so surely they won’t be bitten this time…
The wet belt is the reason I passed on a GM 3.0 liter diesel.
All GM 3.0 liter diesels (Silverado, Tahoe, Escalade…) use a wet belt driven oil pump.
It has a rated life of 150,000 miles.
In Opels genius they put the belt (along with the timing chains that run everything else) on the BACK OF THE ENGINE.
So a wet belt change requires dropping the transmission and is a 9 hour job.
You know what doesn’t have a wet timing belt, or any timing belt, or any plastic timing chain guides? A rotary. Must be the most reliable engine ever built!
(and proceeds forget to add oil on fill up) haha
haha, yep, that’s definitely a risk. Considering that I’ve had to rebuild the engines in both my RX’es…
Fiesta ST 1.6L has a wet belt for the oil pump. My change your oil reminder light just came on for the first time in 100k miles. Dun dun dun….
Anyone done wet timing chains? Just wondering what new and awesome failure modes those would have.
Actually all (I don’t know of exceptions, could be wrong) timing chains are “wet” as they’re within the valve covers of the engine, and by extensions lubricated by oil. Should they be dry, the guides, metal or plastic, would wear so quickly as to guarantee they’d be out of time before the first oil change is due.
Ahh yes, a link to the Chevy Trax forums. A vehicle so bad and horrible to not only own, but also drive, that a wet belt is one of the expensive things you don’t have to worry about breaking… first (or third, even).
They’re better than BMW timing chains.
I don’t mind the idea of a wet belt so much, but I don’t like the level of disassembly required to service them. If its a wear part then it should be relatively easy to replace. If it’s behind all the engine seals then it’s going to be painful.
I just did timing belts on my Odyssey 3.5L V6 and it wasn’t too bad. Got it done in a long afternoon and now it’s good for another 80k miles.
If the Japanese manufacturers haven’t touched it you know it’s poor tech.
..unless it’s Subaru, aka Japan’s own Yugo
I’m guessing the logic behind it was that customers like having a quieter and smoother engine, and regulators will consider even a 1% improvement in fuel economy a win. Furthermore I would bet that the engineers who told them this would happen based on their knowledge of chemistry and real world operating conditions got told to shut up and go back to their nerd stations.
> the engineers who told them this would happen
Those people were let go a decade ago for “not being a cultural fit”.
Given the low value of the subcompact cars these are installed in, this basically amounts to planned obsolescence.
The dealer price to replace a timing belt on a 1.0 Ecoboost is $3-4000. For a 10 year old Fiesta or Focus, you’re often better off getting a new car.
That is what sucks about this if these peeps cannot afford a new car and cheaper cars are planned to be obsolete hopefully there is something you can buy that is affordable and will last.
This is one reason why you hardly see PT Cruisers anymore. Timing belt replacement required at 100k, which costs a couple grand. By that point that’s twice what the car was worth. So it’s either sell the car or let it explode. Either way it ain’t getting fixed.
The interesting thing about the PT Cruiser is that the engine is non-interference. I recently came across a 2009 PT in the junkyard that was very obviously a pristine, low-mile car. The engine was unbelievably clean inside! It was scrapped because the timing belt broke. I can only assume that whoever quoted the job didn’t know that it was a freewheeling engine and they must have quoted a cylinder head replacement. The connecting rods & hydraulic lash adjusters from that one will live on in the 2.4L that I’m building for my endurance racing neon.
From what I understand, because of the cramped nature of the engine bay and how the engine sits in it,.the official procedure for timing belt replacement requires a lot of extra work making it a very expensive procedure. There are ways around it, but the book that shops use make it very time consuming and therefore expensive.
I gotta wonder how much of that would be saved if they’d given the PT a deeper, more clamshell-like hood like the fat-fender ’40s cars it was based on had.
The engine mounting system has a bunch of complexity on the passenger side of the engine where the timing belt sits. The power steering hoses/reservoir & the A/C hoses get in the way too. The cramped nature of the PT underhood area (stupid fender design) makes the car a pain to work on. I could see how an independent shop could probably quote a timing belt replacement with a new tensioner, idler, water pump (driven by the timing belt), and accessory belts for $1000 in labor and maybe $300-350 in parts cost. If they started adding on the replacement of the front crankshaft and camshaft seals or other leak repairs, it could hit $2k or more.
People paid extra for that engine in the first place! The N/A engine was a good deal cheaper, massively more reliable, and made a lot more hp for not much less real world mileage. I don’t think they sold many, though, at least not in the Focus.
As a (possibly biased) former 1.0L owner I don’t think this is completely true.
The Ecoboost made a couple more hp than the 1.6 and a lot more torque. The mileage difference was enough to pay for the engine ($995) in a reasonable time frame too.
Reliability-wise, I’m not so familiar with the reputation of the 1.6 (after all, most were attached to Powershifts anyway), but I put 80,000 most trouble-free miles on my 1.0. I used to work with a guy who had double that (although he was already stressing about the timing belt, going back to my original post).
I had the 1.6 in my fiesta. 150,000 miles and it never had an issue. Radiator fans died, and the alternator failed, but I put a borescope under the valve covers and it was pristine. The transmission on the other hand fucked the car and I sold it for $500 to a shady dealer. Now an old lady drives it not knowing it has the ford racing handling kit and sway bars.
I don’t know about the 1.6. I was thinking of my mk3 Focus, which had a 2.0 with 160 hp 146 lbs/ft. and was rated at 40 mpg (for the DCT, I had a 5MT and averaged 36 on 87 in Boston traffic). I put over 200k on mine with . . . I changed the plugs once because I felt I should even though there was no sign of issue and I had to clean up the connector for the HPFP with some fine sandpaper as it had picked up some corrosion, throwing it into limp mode. Oil changes every 10k with no appreciable usage between changes. Car got totaled, but I drove it off the hood of the Camry that died in the fight and several miles home with a pancaked muffler it struggled to breathe through. Granted, the people with the problems are the ones you hear about most, but there seems to have been a fair number of disappointed 1.0EB owners out there, especially considering how few Focuses seemed to have that option. Not much for complaints about the 2.0 N/A, but the damn DCTs most people bought might have killed them before the engine could have a problem.
On the bright side, the PowerShift debacle ruined most of those Fiestas and Focuses in North America long before the timing belt will wreck the engine.
Kind of like pointing out that one can save money on buying shoes after stepping on a landmine, I know.
The Fiesta with the 1.0 was manual transmission only.
It’s (more than a little) confusing but the Focus 1.0 did offer a traditional auto rather than the PowerShift. An MT article referred to it as the dual-clutch, but the Ford brochure specifically refers to the 2.0’s auto as a PowerShift but not the 1.0. The EPA site also specifically mentions AM for automated manual on the 2.0 and not the 1.0.
The 1.0 was surely a smaller portion of the model mix when it was offered and certainly a fraction compared to the hundreds of thousands of PowerShifts sold to that point.
But it isn’t just in low value or subcompact cars. Plenty of vehicles over $50k use wet belts, if not wet timing belts.
This is why every small car should use a Harbor Freight 670 V twin. Sounds like a Harley or like a church mouse, can reliably make a decent amount of power and uses metal timing gears. Plus it can be attached to a manual or automatic transmission.
I’m being only somewhat snarky.
Would.
Air cooled engines are great, and timing gears are great as well.
By all measures the Audi V-10 Diesel w/ a chest full of timing gears should be reliable as an anvil.
My old VM Motori turbodiesels in my Alfas had timing gears and were the most reliable engines I’ve driven back in the 90’s.
They were also dead simple indirect injection diesels before ECUs and emission controls. There was only 1 electric wire on the engine, going to the shut-off valve on the fuel pump to turn the engine off when you take the key out.
The dry belt interval jumped out to me – 5 years, for a modern belt? eesh. 7 years is what the last few belt holdouts have been on the time interval from what I understand – like Honda, when Toyota still had them, so on. With that at least you’re probably close to the mileage interval based on average mileage.
That’s pretty impressive, our 95 Escort with the 1.9 CVH had a 60,000 mile belt change interval. It also had an accidental service reminder because the crank pulley would spit out its rubber insert every 58,000, prompting a timing belt replacement since we were most of the way there.
Yeah, for older engines I would expect more conservative mileage intervals, back when say, spark plug replacement was often 30k mi and “no tuneup for 100k miles” was a big marketing push. I think most people also lean toward mileage rather than time, so there’s the “but the mileage is low!” objection even though some things would need replacement sooner.
Pretty sure my Toyota has a 7 year/90k interval.
Just had it done, in addition to some other things in the path of work like a new water pump.
I wasn’t expecting just how much smoother and better my engine runs after the replacement.
That’s what most of my searches were indicating for mileage on Toyotas. Honda tends to be 105k under normal driving for a while now. But 7 years did seem to be consistent between both brands for time.
I had an 89 Civic SI for 250K miles. I replaced the timing belt at about 70K intervals. The worst thing about doing the job was having to remove the engine mount that was stuck inside the loop of the belt.
My VW TDI’s (dry) timing belt change interval is 130,000 miles. When I replaced it, it was 8 years old and it looked like new (no cracking/flaking, and the tensioner was a bit past half-way between the limits but still within spec).
I figured the problem would be that they would slip with all the lubrication.
Well, they’ll certainly be slipping when the teeth are stripped clean off!
Sigh, 25+ year experience maintenance engineer here. Oil and elastomers do NOT play well together. Who thought this was a bright idea???
“Who thought this was a bright idea???
Some Accountant, you silly engineer.
I hate all timing belts. Chains or gears are much more reliable in most cases. As I have said on here before my dad killed his chevy sanic by improper install of its new belt (he left some block in place that is supposed to hold things in place and to be taken out once the new belt is back on)
I’m all for gears but only if they’re steel.
I’ve been working on cars for the last two decades. Give me a dry belt over a chain or wet belt on any overhead cam engine. I’ve had to replace too many stretched chains or broken guides, or failed cam phasers, especially recently with BMW N20/N26 and Ford Ecoboost 3.5 engines. Dry belts? You know when the change is due, you can get an estimate well in advance, and you can budget for it. Hell, on quite a few dry belts, you need zero special tools and they can be done in the driveway by your average amateur/hobbyist gearhead.
Makes sense only vehicles I currently own have are chains or gears and haven’t had to replace any of them and all of the chains are either GM or Toyota and the gears is a Cummins. But I have heard the horror stories with BMW or Audi chains. Hopefully none of my vehicles will have similar issues.
I would think that the belts stretch too. On my old integra it was the timing belt tensioner that took out the engine. Now on the wrx the chain sounds like crap on startup until it gets some lube on it after sitting for the weekend
Ford 3.5 Ecoboost has enter the chat. Timing chains driving not only the cams, but the water pump, so when it craps the bed, there’s also the potential to dump coolant into the plastic pan. But the first issue is, can phaser rattle on cold start, then, as miles accumulate, the plastic lined chain guides disintegrate. Audi’s 20 timing gears are starting to look better all the time. It might sound cool to have them howling away as the engine revs to 6K rpm. 😉
The one caveat I have is, the belt should have the timing marks painted on it. I did my daughter’s Pilot and it was a bitch lining up the little pip on the cam wheel w/ the notch on the valve cover for the rear bank of cylinders. Only later did I see a v6 cam belt w/ the stripes on the outside and it made so much sense.
This is a strange reason to hate all timing belts… So your dad didn’t remove the block that holds one of the cams in a fixed position when replacing a belt, and that block did its job and kept the cam from moving when cranking the engine likely causing the belt to skip or strip and pistons hit valves… so all belts are bad? Are all disk brakes bad because you forgot to install the pads once?
Oh it isn’t because he messed up was just sharing the story. I do not care for them because they need to replaced around 100k miles give or take and if not replace in a timely manner it can lead to costly repairs.
Or you can go with a timing chain that gradually stretches, throwing the timing off in 100,000 – 150,000 and decreasing your engine performance until it gets bad enough to jump a cog. And speaking of costly repairs, check out the price of a timing chain set.
I think way too many people speak so fondly about the reliability of timing chains based on the tensioner-free super-short chain for the old cam-in-block V8s. Modern timing chains are a nightmare, in my opinion.
The old “short” timing chains weren’t all that and a bag of chips. I had a 318 mopar that stretched the timing chain so much that it fell off the bottom of the crank sprocket when the engine was shut off then bent the valves in 2 cylinders when Herself tried to start it. So, yeah, not that great either. At least w/ the old engines you could remove the distributor cap and turn the crank back & forth to see how many degrees of slack the chain had to the camshaft.
not to mention how easy a timing belt replacement is compared to a chain & guides job, especially when you have to do the job twice to fix that timing cover oil leak you got after the first attempt 🙂