Letting Timing Belts (Chains?) Go too Long?

Automotive
#1

Continuing the discussion from Bridgeport…Ohh boy:

Please expound! I was looking into this recently as my vehicle is a 2007 and has ~130K on it. But I got trapped/sucked into the “101+ forum posts that all disagree with each other” syndrome.

Is there any indication or symptoms that a timing belt (or chain in my case, I think…) needs to be changed? My best understanding is that a timing chain, unlike a timing belt, should be “life of engine”, assuming one has ket up with oil changes per the manufacturer’s maintenance schedule/recommendations.

Is there a way to inspect this part? Again, my understanding is not, but…?

#2

When I was in college and quite broke, I decided that rather than change my timing belt (‘91 Honda CRX), I’d take a look at it instead.

I removed the top timing belt cover and rotated the engine by hand until I’d gotten a careful look at the entire belt. It looked fine.

Within 10k miles of that, a number of teeth sheared off the belt and while it didn’t break, it trashed the engine. Every valve (x16) bent, every valve guide cracked.

It was a $2000 screw up and that’s with me doing all of the major work.

Eking a few more miles out of a timing belt is serious false economy.

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#3

What are you saying you should have done differently?

#4

Replaced it at that mileage whether I thought it needed to be replaced or not.

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#5

One very CRITICAL Question: Does the engine have Interference or Non-Interference valves. If it has inference values and the timing belt fails - you trash the engine as valves are driven into pistons. If non-interference, if it just slips a tooth you’ll be able hobble somewhere or it will just feel like a total loss of power (Experienced both in my RAV4. First time was only about 15,000 over recommended change. Second time was about 5,000 short of time - strongly recommend you get OEM replacements belts)

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#6

I see…one of the “confusions” out on some Toyota (my make) forums is the distinguishment between life/replacement schedule for a timing belt vs. a timing chain. It appears from my reading that chains are generally designed/built for the life of a car, as opposed to belts, which do wear.

#7

That’ll be in the owners / service manual. If manufacturer says lifetime on a chain then I’d be comfortable with that in the absence of any reason to think my chain had a problem.

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#8

This was probably true for engines I grew up on (age of dinosaurs) because at 100,000 miles engine need to be rebuilt or getting there. Today engines often go 250K-300K. From what I’ve seen, while chains do stretch and will throw the timing off progressively, it seems most problems are with the tensioners and guides failing before the chains.

Old V8’s had the timing chains up front and were easy (relatively) to replace. But many engines, like my Ford 5.4L has two timing chains. One bank the chain is up front, not too bad. The other bank is at the back of the engine requiring the engine to be pulled.

One thing I love to look at is the Miata engine: not sideways mounted, the two cams and timing belt are right - changing the is super easy.

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#9

This is an actual picture of Kessinger’s first car:

image

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#10

I hate it when I get tagged in photos.

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#11

Hey! I had one of those… :wink:

DD

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#12

Interesting. Which year/model/application did ford go to that chain layout for the 5.4? My 05 F150 5,4 modular V8 is one where the chains were designed as a lifetime part, it have proven otherwise in the field. The two primary issues appear to be chain tensioner oil seals that lead to low oil pressure, and loose chains damaging the guides, which in turn damages the chains, and cam phasers that fail in far too many ways, leading to slop, which leads to impulse forces as things bounce around in the slop, and tears up the chain. But it doesn’t usually lead to catastrophic outcomes, unless the oil pressure drops enough that the valve train takes enough damage to drop a valve and kill things. They usually just get noisier and run worse, with more parts needing to be swapped until you finally go do the work.

Butt the good news is that on this one, both chains absolutely are on the front.

#13

Mine is a 2005. The chain itself doesn’t seem to be the problem, it’s the tensioners/guides that wear out and fall apart. It’s not just Fords, lots cars have the problem. So “it’s not the timing chains going bad” it just all the structure that supports

[) Ford Triton 5.4L Timing Chain Issues Alright – there are a few things to discuss here. We’re simply referring to these problems as timing or timing chain related. The timing chain itself can be an issue on the 5.4L engine. However, timing chain tensioners and variable valve timing (VVT) are known trouble areas too. The 2-valve 5.4 Triton does not have VVT, so that’s isolated to the 3-valve Triton.

We’ll avoid getting too technical for now. Long story short – timing is a critical part of proper engine operation. If these issues aren’t resolved in a timely manner further damage can occur. Usually 5.4 Triton timing problems arise from a loose timing chain. The chain then slaps around a little bit, and given enough time that’s all it takes to break the timing tensioner. Some 5.4’s also run into issues with the VVT and that’s primarily due to the cam phaser breaking.

When a timing chain or tensioner fails it’s possible to throw timing off pretty far. Ultimately, that may lead to the 5.4L Triton valves contacting pistons. That’s an engine out failure at the least, and may even destroy the engine beyond repair. It’s not extremely common for this to occur, so we don’t mean to scare anyone. However, it is possible which is why these are important problems to look out for.](The 4 Most Common Ford 5.4L Triton V8 Engine Problems - 5.4 Reliability)

#14

How are timing chain related issues diagnosed or detected? Not a chain failure, necessarily, but indications that chain (or supporting components like tensioner) need to be inspected and/or replaced?

#15

Timing may be off. Can usually hear the slapping noise has been my experience.

I prefer chains - I’ve never had one fail or any of my friends. Only one I personally know of was on a really tricked out high revving with high strength/pressure springs in the valve train. But that was again in the age when dinosaurs roamed the earth.

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#16

I’ve had a timing chain stretch. It was actually the day after I switched from Pennzoil to Valvoline or Castrol. It just quit running. It was an 84 Oldsmobile Delta 88 with the the 307. Not very many miles either. 85,000. However the timing sprockets were dicast. I still have it as a trophy on my wall in my garage.

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#17

That’s what I have noticed while researching…apparently chains stretch over time, especially if oil is not changed or drops too low, i.e. additional friction/effort for chin distorts it. I never saw it discussed on relevant forums what the symptoms of a stretched chain were, though.

@Photomancer mentioned one above…I guess there would be a drop in engine performance/acceleration power as a result? But that is true for several things, i.e. old spark plugs.