Results of measuring timing chain stretch via cam phaser adaptation.

[Novarider]

Strange, I wonder if they had a bad lot run through or a different plant manufacturing them as some people have huge stretch and some looks like theirs do not stretch much.

The idea of me changing these myself scares me, I am relatively knowledgeable but never gone this deep into an engine especially putting the car into service mode but the price difference might be enough to make me take the plunge. I’ll probably get a quote from the dealer to get a better idea. It looks like most people are in the $1500 range from a dealer.


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Service position is very easy to do. No reason to be intimidated by it.

[aschmi07]

2014 CAED 77k miles -2.73. Should be good for a while still.

[Theiceman]

2014 CAED 77k miles -2.73. Should be good for a while still.

barely half life ... at that rate you have about another 5 years.

[fastboatster]

had camshaft adaptation checked on some 2014 b8.5 with 79kmiles I was looking at last Friday. with -3.98 degrees of adaptation, PPI showed that the timing chain tensioner extended out about 7-8 teeth and tensioner/chain needed replacement soon.

[aschmi07]

had camshaft adaptation checked on some 2014 b8.5 with 79kmiles I was looking at last Friday. with -3.98 degrees of adaptation, PPI showed that the timing chain tensioner extended out about 7-8 teeth and tensioner/chain needed replacement soon.

Hmm yeah did not bother checking the tensioner itself--should probably check next oil change. thx

[Theiceman]

yup those numbers sound about right ...

the issue is the chain .. i was fully confident i could compress my new style tensioner , put a new chain on and be good to go ...i of course didnt .. but when i did mine it was on the very last indent and was fine.

[DaPlatypus]

Figured I'd add some data...

2010 @ ~81,000 with original chain & updated tensioner: -4.86

[Theiceman]

yeah based on what we have seen i think the chain lasts about 100K mile or 160k km .

[RDA990]

2013 A4 87,000 Miles
Engine Code: CMPA
Engine Build Date: 4/13

The car should have one a revised tensioner but I'm not sure about the chain. Within the past week I've been seeing -5.23°, -4.30°, and -5.19°. This with the vehicle at operating temp but had the ignition restarted (turned off then back on a few minutes later). I will visually inspect the tensioner this weekend to be 100% sure it is a revised model and check how extended it is. Based on what I see I'll determine if I have to do the job in the next few weeks before winter gets here or if this can wait until spring 2020.

Also, what is the correct way to get an accurate phase adaptation degree? Drive the car until operating temp, leave it idling, without shutting it off check the degree? I don't think the numbers I have been getting are accurate since I always check them after the car was turned off.

[old guy]

Engine up to temperature, car at idle. Read in real time. Rev the engine up to 2500 rpm and watch for increases. Take the highest reading.

[mtroxel]

what is the correct way to get an accurate phase adaptation degree? Drive the car until operating temp, leave it idling, without shutting it off check the degree? I don't think the numbers I have been getting are accurate since I always check them after the car was turned off.

Not sure there is a "correct" way. But I always leave mine on, idling, after I drive it, then check. Sometime when I have nothing to do I'll compare the reading I usually take, then take it after I turn it off. I'm betting there's a difference.

[Theiceman]

2013 A4 87,000 Miles
Engine Code: CMPA
Engine Build Date: 4/13

The car should have one a revised tensioner but I'm not sure about the chain. Within the past week I've been seeing -5.23°, -4.30°, and -5.19°. This with the vehicle at operating temp but had the ignition restarted (turned off then back on a few minutes later). I will visually inspect the tensioner this weekend to be 100% sure it is a revised model and check how extended it is. Based on what I see I'll determine if I have to do the job in the next few weeks before winter gets here or if this can wait until spring 2020.

Also, what is the correct way to get an accurate phase adaptation degree? Drive the car until operating temp, leave it idling, without shutting it off check the degree? I don't think the numbers I have been getting are accurate since I always check them after the car was turned off.

yeah just idling after a drive is how i do it. I think you are perfectly fine till next year with those number. you will have a new tensioner and old style chain. you are right on the trajectory for a 100K mile chain service.
anyone have the balls to put there new style tensioner back in ? and just throw a new chain in ? .. i totally weineed out and replaced the tensioner.

[mtroxel]

I would add this observation. Every internal combustion engine sold in the last 15 years has had overhead cams. All of those have either a belt or a chain. So take all the measurements you want, but the history of engine suicides in the last 15 years tell us you are playing Russian roulette if you are near 100,000 miles and have not paid attention to the timing system in your car. Am I wrong?

[Charles.waite]

IMO, you’d have to be insanely cheap and/or stupid to not replace the tensioner if you’re in there. Reinstalling it due to cost is a false economy.

[Theiceman]

IMO, you’d have to be insanely cheap and/or stupid to not replace the tensioner if you’re in there. Reinstalling it due to cost is a false economy.

oh of course but inquiring minds want to know ....

[fastboatster]

I would add this observation. Every internal combustion engine sold in the last 15 years has had overhead cams. All of those have either a belt or a chain. So take all the measurements you want, but the history of engine suicides in the last 15 years tell us you are playing Russian roulette if you are near 100,000 miles and have not paid attention to the timing system in your car. Am I wrong?

Imo this is mostly correct for DI engines where timing chain also drives hpfp via camshaft. That does put more stress and load on the chain. If you only have port injection, then timing chains usually last, keyword is usually. Depends on the make and model, too.

[stres-tm]

i was thinking about this today, if the chain has little to no stretch then the tensioner is not moving back and forth presumably causing the failure so if i look at my current numbers (-2.75°) with old style tensioner maybe these two are more intertwined than i previously thought. i.e high stretch could cause earlier failure due to more lateral movement? either way i will change this out to the new style just was thinking about it earlier and thought we could discuss?

[old guy]

i was thinking about this today, if the chain has little to no stretch then the tensioner is not moving back and forth presumably causing the failure so if i look at my current numbers (-2.75°) with old style tensioner maybe these two are more intertwined than i previously thought. i.e high stretch could cause earlier failure due to more lateral movement? either way i will change this out to the new style just was thinking about it earlier and thought we could discuss?

The issue with the early style tensioner was failure of the clamp/pawl design. Adaptation numbers are simply adjusting for overall wear. Low adaptation numbers do not negate in any way the design flaw of the tensioner.

The tensioner doesn't move in and out more because of the wear. It simply indexes out to accommodate the wear.

[stres-tm]

But wouldn’t more indexing cause the pawl to adjust to the new setting causing the clamp to lift and be more prone to fail?

I’d bet there is some correlation between when it fails and overall stretch but not enough data points to be sure


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[old guy]

But wouldn’t more indexing cause the pawl to adjust to the new setting causing the clamp to lift and be more prone to fail?

I’d bet there is some correlation between when it fails and overall stretch but not enough data points to be sure

It only indexes out to accomodate for wear. It doesn't index back and forth. The problem occurs at start up. When oil pressure is applied to the tensioner it will move out to the tensioned position. This puts pressure on the metal clamp band. If it pops off the tensioner or the pawl fails it is no longer held in the proper position resulting in failure.

[old guy]

See if this makes more sense. Here's the adjuster without the spring clamp. The adjuster moves out as far as it can to maintain tension. this causes the pawl to index on the notches. You can see the amount of travel available in the oval opening. With the engine off and no oil pressure the pawl moves to the back of the opening and travel is limited by the pawl locking into the notch.

When you start the engine the oil pressure added to the spring pressure moves the tensioner out to maintain tension on the chain. It's this movement that causes the spring/pawl mechanism to fail. This can occur regardless of the starting position of the tensioner since it has already adjusted for the component wear.



It sounds like you are trying to convince yourself that a low adaptation value equates to a lower risk with the old style tensioner. Unfortunately that just isn't the case. The risk of failure is the same regardless of the adaptation value.

[Theiceman]

This thread is basically to mo itor hsin stretch so we know when to proactively replace chain and tensioner. Outside of this there is more than enough data to show you are playing Russian roulette if driving around on old t
Style tensioner regardless of stretch.

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[Theiceman]

while i am here i thought i would provide an update .. while i was playing with VCDS the other day trying to use it to learn AC for my buddy i pulled a snapshot of where I am with respect to this about 5K miles after my engine rebuild.

seems to be holding well.

[CanAvant]

So, my bank one phase is -4.88 on my 2014 allroad with 2 months of cpo left on it.
Is there any way to get the dealer to deal with this before my warranty runs out? Symptoms? Because I know they’ll disclaim the phase theory ;(

90000 km! Yikes

[old guy]

So, my bank one phase is -4.88 on my 2014 allroad with 2 months of cpo left on it.
Is there any way to get the dealer to deal with this before my warranty runs out? Symptoms? Because I know they’ll disclaim the phase theory ;(

The short answer is no.

Technically there is nothing wrong with your engine. The cam phase adjustment is simply the ECM adjusting the baseline cam position to accomodate for the wear of the components. Your 2014 should have the redesigned tensioner. I haven't heard of any tensioner failures with the new style tensioner as long as it is within the total adjustment range.

You could ask them to make a visual inspection to see how far the tensioner is extended. But quite frankly I would be surprised if they agree to the request.

[Theiceman]

The short answer is no.

Technically there is nothing wrong with your engine. The cam phase adjustment is simply the ECM adjusting the baseline cam position to accomodate for the wear of the components. Your 2014 should have the redesigned tensioner. I haven't heard of any tensioner failures with the new style tensioner as long as it is within the total adjustment range.

You could ask them to make a visual inspection to see how far the tensioner is extended. But quite frankly I would be surprised if they agree to the request.

I agree with this. My 2014 had over 8 degrees with no issues beyond vibration at idle. Car is technically working and there is nothing for Audi to fix.

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[elscotto80]

New data point: -3.56* with 131k mi on motor, new tensioner, guides, seal, etc @ ~75k mi. I did not do the chain at that point, so seems that the chain is wearing just slightly.

[Theiceman]

New data point: -3.56* with 131k mi on motor, new tensioner, guides, seal, etc @ ~75k mi. I did not do the chain at that point, so seems that the chain is wearing just slightly.

If you think about it it is right on spec. 3.56 on 55k is pretty much what I would expect.

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[elscotto80]

Yup. So at this rate, a new chain and tensioner will be needed around 200k?

If you think about it it is right on spec. 3.56 on 55k is pretty much what I would expect.

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[old guy]

If you think about it it is right on spec. 3.56 on 55k is pretty much what I would expect.

Here's another way to look at it. My adaptation was -2.4° at 55k miles. New style tensioner, old style chain. Since elscotto80 only replaced his tensioner and wear pads his chain has 131k miles of wear.

Lets assume his new wear at 55k is similar to mine. Subtracting the -2.4° from his -3.6° of adaptation would indicate that the chain wear adaptation alone at 131k miles would be in the neighbourhood of -1.2°.

Obviously there are numerous other factors but overall definitely less than I would have expected.

[elscotto80]

Good points. Certainly good to know it's got a lot of life left.

Back when I did the timing stuff, I wasn't very aware of the issues most of of face with it. The shop recommend the work, which I eventually got reimbursed. Win win.

Here's another way to look at it. My adaptation was -2.4° at 55k miles. New style tensioner, old style chain. Since elscotto80 only replaced his tensioner and wear pads his chain has 131k miles of wear.

Lets assume his new wear at 55k is similar to mine. Subtracting the -2.4° from his -3.6° of adaptation would indicate that the chain wear adaptation alone at 131k miles would be in the neighbourhood of -1.2°.

Obviously there are numerous other factors but overall definitely less than I would have expected.

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[Wartowski]

My vcds show information like this after 30 mins normal traffic drive, how is it look? I have A4 b8.5 160k km. Oem chain and tensioner as I know. Why those 2 information degrees is my car 15.x and other have 28.xxx?

[elscotto80]

Did you take these with the motor running?

My vcds show information like this after 30 mins normal traffic drive, how is it look? I have A4 b8.5 160k km. Oem chain and tensioner as I know. Why those 2 information degrees is my car 15.x and other have 28.xxx?

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[old guy]

Which engine?

[Wartowski]

I did that motor idling after 30 min drive. Engine 1.8tfsi cjeb (125kw), facelift.

[mtroxel]

OK, slightly different motor. So its hard to compare those camshaft adjustment values. You're right, on the 2.0 we routinely see 28° +/- instead of the 15° range you’re seeing.

[Wartowski]

6 months earlier my results were like this (not driven, just idle long time at normal temperature):

Camshaft adjustment intake bank 1:specified value 15.0°
Camshaft adjustment intake bank 1: actual value 15.2°
Camshaft adaptation intake bank 1: phase position -0.3°
Camshaft speed: (RPM) 808 /min
Calculated oil temperature 101.0 °C

[Theiceman]

Yeah cant compare. But if I were to say anything it would be that .3 degrees phase adaption is very good regardless of target.

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[Danzzo]

Is P/N: 06k-109-158-AD an updated chain or should I get a different chain installed? I'm at 120k miles right now but the timing chain service was done at 68k miles:

[Charles.waite]

That’s not the newest chain revision. I wouldn’t necessarily tear the engine apart to replace it (unless the engine is already torn apart) because you can always monitor chain stretch with the cam phase adaptation value in VCDS. Chain failure is unheard of, even though stretch is common. I’d not be concerned assuming the tensioner is the revised design.