Timing Chain Guides

[dishdude]

Thanks for the info. I'm neither concerned nor worried about tensioner and chain wear as suggested by another poster, just curious about the systems and, of course, how they may affect the Camry engine. The more you know, the better your luck.

I believe that once wear gets to a certain point, it does accelerate, but that's just a belief. I've not looked into it very deeply.

To be fair, this statement made it sound like you were.

This discussion has got me thinking about when to do the work on the Camry should I decide to keep it for the long haul.

Outside of a few complicated and problematic designs, timing chains are extremely reliable and last the life of the car. I'd venture to say most cars end up at the scrap yard with their original timing components. If the Camry were a problematic design, we'd know just based on the high number of those engines out there. I'm sure you don't abuse it, check the oil level regularly and keep to a reasonable OCI. Nothing to be concerned about here.

 

[D60]

To be fair, this statement made it sound like you were.



Outside of a few complicated and problematic designs, timing chains are extremely reliable and last the life of the car. I'd venture to say most cars end up at the scrap yard with their original timing components. If the Camry were a problematic design, we'd know just based on the high number of those engines out there. I'm sure you don't abuse it, check the oil level regularly and keep to a reasonable OCI. Nothing to be concerned about here.

I know I'm a one-note piano but most 3V Fords wind up at the scrap yard because of their timing set.

But yes, your overall point is valid and I'm not trying to be argumentative

 

[brages]

I'd venture to say most cars end up at the scrap yard with their original timing components.

I'm not arguing with you, either, just making an observation: many cars end up in the junkyard at low (to me) mileages. In 2006, the NHTSA said the average lifetime mileage of a passenger car is just a bit over 150,000 miles. You can definitely find vehicles in the 150k range at the local pick-n-pull.

My opinion is that a well-engineered car should be able to double that with regular minimal maintenance.

 

[Shel_B]

To be fair, this statement made it sound like you were.

Outside of a few complicated and problematic designs, timing chains are extremely reliable and last the life of the car. I'd venture to say most cars end up at the scrap yard with their original timing components. If the Camry were a problematic design, we'd know just based on the high number of those engines out there. I'm sure you don't abuse it, check the oil level regularly and keep to a reasonable OCI. Nothing to be concerned about here.

The original question was about guides, not chains. Guides were mentioned five times in the original post, including the subject of the thread. Chains were not mentioned at all.

There are myriad instances of damaged and worn guides causing serious, even catastrophic, engine failures in almost uncountable engine repair and teardown videos. Very few of those videos show damage to the chain.

 

[dishdude]

The original question was about guides, not chains. Guides were mentioned five times in the original post, including the subject of the thread. Chains were not mentioned at all.

There are myriad instances of damaged and worn guides causing serious, even catastrophic, engine failures in almost uncountable engine repair and teardown videos. Very few of those videos show damage to the chain.

It's the same discussion.

 

[Shel_B]

It's the same discussion.

That explains a few things ...

 

[Exhaustgases]

Timing chain guides are the inexpensive to manufacture system that all auto makers seem to choose. Heat and vibration, no rolling element and garbage material is why they don't last. Besides no manufacture would want them to last. Just can't sell parts and service or new cars if they do.
OHC is not a design for longevity.

 

[D60]

Timing chain guides are the inexpensive to manufacture system that all auto makers seem to choose. Heat and vibration, no rolling element and garbage material is why they don't last. Besides no manufacture would want them to last. Just can't sell parts and service or new cars if they do.
OHC is not a design for longevity.

It does fascinate me that it works at all, and indeed it works relatively well. I mean if my layman brain was designing such a system never would I think it would work to have a metal chain continously rubbing on a "plastic" surface as a means of retaining chain tension.

Part of the problem I see -- especially with the lesser tensioners -- is that they struggle to bond or attach the plastic to the metal backer, such that if the plastic cracks or splits the entire piece of "plastic" falls away. If they could somehow retain it more akin to brake pads, a single crack or chip wouldn't mean 100% of the friction material falls off.

 

[benjy]

neighbors 3.5 ecoboost had one chain under warranty + when the SECOND one went bad he dumped the truck, ONLY 70 thou THEN he buys a newer used one his dealer friend sad was cured GUESS what it got bad not long afterward!!!

 

[wemay]

Start around 3:00. He specifically talks about chain slap causing guides to fail.

Starting at ~5:45 he shows the chain wore through the plastic AND the metal backer! The piston of the tensioner punched through the guide and the piston is now in contact with the chain.

I can't believe he said "the chains are fine" at 11:39 after seeing all that carnage. I would have thought they were trash now too. Thanks for sharing.

 

[wemay]

Notice the uptick in chain wear over the last 30 years. But, the engines are squeaky clean. Noticed the uptick in excessive oil consumption too. And, no one argues flat tappet cam wear even though the blame game was a joke. Ford also doesn't care for the newer diesel oil specs with their older engines. Fuel dilution was ignored for too long by too many. Thin oil sure helps MPG but what about wear?. Lower zddp levels sure help with o2/AF sensor and catalytic life... Should a sensor or catalytic converter outlast an engine? Or should those cheaper parts simply be replaced as needed?

The wear is happening. The automakers, and oil/additive companies, seem to be continuously behind what is happening out there, in the real world. The R&D is happening at the consumer level.

So, I use a grade thicker oil, and/or maybe bottle or 2 of thicker oil, and I use oil with more zddp than required, a pretty good oil filter, and a typically shorter than 'recommended' interval. All my timing chains/guides/tensioners/vvts are doing pretty good. I don't suffer from oil consumption issues(except for the 2-strokers and rotaries). Most of my engines are doing pretty good with compared to neighbors/relatives/colleagues/coworkers/contractors, and definitely better than the 100's of threads started in 100's of forums complaining about engine noises, sludge, oil consumption, and failures.

But, the thought of changing the oil out a little earlier, using a quality oil/filter, using the dipstick often, being selective with fuel/oil/filters/intervals, is beyond the capability of zombie sheeple drones only worried about their drivethru products and phone glued to face lifestyle. More trust their radio talk show or youtube/instagram/tictoc personality. If there is something you can do to prevent the make believe 'inevitable', would you do something about it?

Its just all antidotal anyway, just like automaker R&D. So, what are you going to do about it?

I don't surrender to "inevitable". And, my antidotal experiences are certainly against the grain of the fools that surrendered.

I also don't have a perfect commute or boring driving style. I could 'egg on gas pedal drive' pretty much any engine for a long low wear life but don't like causing traffic jams(see these clowns daily).

Excellent post.

 

[Cujet]

neighbors 3.5 ecoboost had one chain under warranty + when the SECOND one went bad he dumped the truck, ONLY 70 thou THEN he buys a newer used one his dealer friend sad was cured GUESS what it got bad not long afterward!!!

Completely preventable. It’s not at all difficult to reach 400k miles with these.

The solution is M1 EP at 5000 mile intervals.

 

[350Rocket]

Thank you. That's a good starting point for further investigation. I discovered that Stanyl has a melting point of 295-deg C, so engine heat should have little if any, effect on the material. I need to do more reading.

I'd like to find out what material the guides are in my car, not that there's much I can do about it at his point. It's just a matter of curiosity.

These "plastics" seem to be relatively new materials. I wonder what was used before they became available. Since these materials came into general use around mid-20th century, I wonder if any cars used timing chains AND needed guides prior to WWII, which, to my understanding, seems to be the time that the development of plastics and polymers started to accelerate. Carothers developed Nylon around 1939 and started working with synthetic rubber in the early 30s. I know that there were just a handful of engines using overhead cams prior to 1910. I'm guessing that they were gear driven.

Anyway, thanks ... some interesting reading lies ahead.

They used nylon coated timing gears on most v8 engines back in the 70s and into the 80s. They were known to fail early, though some seemed to last a lot longer than others. Oil changes were probably a huge factor, especially with inferior oil of the time. They didn't have guides though.

 

[350Rocket]

I did the waterpump in our 2009 Flex over 3 years & 60k kilometres ago, the decision was to do all the chains and guides while in there, but I admit the old guides looked virtually as good as new with 206K Kilometres on them. Yes this Flex had a regular diet of PP 5W20, but I have no idea if this was the explanation.

My mom's 2010 Taurus needed the water pump at 360,000kms. It got sold cheap to a mechanic I used to work with and he fixed it. The timing chains were worn out and adjusters were completely maxed out. If had 3k oil changes, all conventional, mostly bulk Pennzoil, and whatever the dealer used when it went there. She bought it new.

 

[SHOZ]

The chain on my Gen Coupe 2L had stretch but the guides didn't have any wear at 100k miles.

 

[SC Maintenance]

I think part of the problem might be that belts were designed to be serviced - usually like 75K miles, so servicing was part of the overall design plan.

Chains were supposed to be the design life of the engine - so engineers went crazy out of the box with the design and when the guide material didn't prove adequate, well the designer had moved on. It worked on paper. Early VQ40's had both bad material that failed on the secondary tensioners, and poor bonding and overall design of the secondary tensioners. Both had problems. They figured this out and not only improved the material, and improved QC of the chain links to ensure no burrs, but they also added something to some of the links to carry oil more readily in the chain. Later builds have had no such problem, but if you look a the complexity of the routing its no wonder it had issues.

Also correct me if I am wrong, but DOHC engines with belts usually had the belt driving one cam and a direct gearing to the second cam. I am sure that's now always true, but the ones I have seen have been.. With timing chain driven engines they often have secondary chains - so your adding multiple chains and guides that can fail.

 

[brages]

Also correct me if I am wrong, but DOHC engines with belts usually had the belt driving one cam and a direct gearing to the second cam. I am sure that's now always true, but the ones I have seen have been.. With timing chain driven engines they often have secondary chains - so your adding multiple chains and guides that can fail.

I don't think that's correct. One pulley for each cam is common for DOHC with timing belt.

 

[SC Maintenance]

I don't think that's correct. One pulley for each cam is common for DOHC with timing belt.

So this design would be unusual then? I haven't had a whole lot of experience with timing belts.

 

[brages]

I don't think it's weird for a V engine. I think inlines usually do the pulley on each cam, though.

 

[Exhaustgases]

They used nylon coated timing gears on most v8 engines back in the 70s and into the 80s. They were known to fail early, though some seemed to last a lot longer than others. Oil changes were probably a huge factor, especially with inferior oil of the time. They didn't have guides though.

And older yet some times phenolic was used to make gear teeth in some gear drive setups, the only reason to use non metal in those applications was to try to make the engine quieter for some fussy goofs. The non metallic gears and sprockets had low durability, and pretty much destined to fail at around 100,000 miles so maybe that was also part of the plan as well.