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Timing Chain Tensioner Failure

icy604

Passed Driver's Ed
I'll start this off by giving a brief description of my car and it's condition...

Disclaimer: I am fully aware of the issue with the timing chain tensioner and it's indiscriminate, sporadic failure on any EA888 gen 1 motor.

I drive a 2011 GTI 6MT with 128,000 kms on it. I've got APR Software and and APR Downpipe. I meticulously do 5k km oil changes and my car has had a carbon cleaning, new plugs, coils, LPFP, and injectors all within the past year.

My story begins earlier this week on a drive up to a local mountain. I enjoy driving my car, and will say that I enjoy driving quite spiritedly, as I was on this day. My car was running perfectly on the climb up to the parking lot at the summit of the mountain, but upon arrival I noticed when I put the car into neutral from about 30 km/h in 2nd gear to coast and find a parking spot. I immediately noticed that the revs dropped down to about 300-400 rpms which I found very strange. I put the car back in 2nd and it started feeling like it was misfiring and sputtering. I figured that this couldn't possibly be a fuel or ignition problem so I assumed the worst, shut the car off and pulled out my OBD Eleven. There were zero engine fault codes, not even one misfire. I didn't want to sit there and crank the motor if the tensioner failed so I got it towed to my work (a Porsche dealer with lots of ex VW techs, I am actually training as a tech as well). We got the car in the shop, pulled the plugs and coils out and borescoped the cylinders. We didn't see anything indicative of valve-piston contact (no crescent-shaped contact marks or shiny marks on the pistons). After this we were manually turning the engine and it moved freely with no concerning noises or resistance, so we threw the plugs and coils back in and started the car up. The car ran poorly and we were monitoring misfires on a vagcom, seeing random misfires on all four cylinders and after about 15 seconds the car finally threw a cam/ crank sensor correlation fault. When we saw the fault, we shut the car off immediately, pulled the plugs again and we started to turn the engine manually again. We began slowly turning the engine and after about 45 degrees of rotation the engine didn't want to turn anymore.

So in my mind there are a few possibilities as of right now:

1. The chain slacked off due to lack of tension and it is bound up in the timing case right now, causing the engine to not want to turn.
2. The engine has reached a point of not wanting to turn because timing has jumped far enough to cause valve-piston interference (maybe that's what we are feeling with the resistance to rotation).
3. Timing jumped just enough initially to cause the car to run poorly, but not bend the valves.

My understanding is that the car would still run if the timing was advanced by a couple of teeth. My question is if the valves were bent, would the car run at all? Does anyone know how much forgiveness these engines have in terms of timing advance before bending valves? I've read some people get lucky and jump 6 teeth or less and only need to re-time the engine. I am hopeful that we got lucky and the fix will just be re-timing the engine.

As of right now I have new chains, guides, tensioners, and replacement hardware/ gaskets coming, but we cannot work on the car until Monday.

Has anyone got any experience they can share with me for the time being to ease the tension... (pun intended)
 

Joe_Mama

Autocross Champion
Disclaimer: I am fully aware of the issue with the timing chain tensioner and it's indiscriminate, sporadic failure on any EA888 gen 1 motor.

So you knew about the tensioner problem and decided to not address it?

If it was the old tensioner, it definitely let go and you definitely jumped timing and you definitely have bent valves. Yes the car can run with bent valves if they aren't bent severely.

You jumped in and bought all new timing components without even knowing for certain if it even slipped time. Now if you go ahead and install all your new timing stuff and the car still runs like shit it's because you bent the valves and need a new top end.
 

icy604

Passed Driver's Ed
So you knew about the tensioner problem and decided to not address it?

If it was the old tensioner, it definitely let go and you definitely jumped timing and you definitely have bent valves. Yes the car can run with bent valves if they aren't bent severely.

You jumped in and bought all new timing components without even knowing for certain if it even slipped time. Now if you go ahead and install all your new timing stuff and the car still runs like shit it's because you bent the valves and need a new top end.
It most certainly jumped time already because of the cam/crank correlation faults. The plan is not to run the car as soon as the new timing components are installed. The plan is to install the components and then conduct a leak down test for each cylinder.
 

Joe_Mama

Autocross Champion
It most certainly jumped time already because of the cam/crank correlation faults.

Uh... ok? i already said that


If it was the old tensioner, it definitely let go and you definitely jumped timing

So youre evading whether or not you were driving on the old tensioner so ill just assume you were.

In that case, like I said before you most certainly have bent valves. Just because you cant visually see the bend doesn't mean it isn't there.

You can buy new valves and hope for the best or you can buy a new (used) motor/top end. That is the most likely outcome.
 

icy604

Passed Driver's Ed
Uh... ok? i already said that




So youre evading whether or not you were driving on the old tensioner so ill just assume you were.

In that case, like I said before you most certainly have bent valves. Just because you cant visually see the bend doesn't mean it isn't there.

You can buy new valves and hope for the best or you can buy a new (used) motor/top end. That is the most likely outcome.
My understanding is that there is some forgiveness with how much it jumps time before it bends the valves. I've heard of guys jumping only a few teeth and only having to re time the engine and calling it a day
 

Joe_Mama

Autocross Champion
It isnt impossible but it is highly unlikely. Prepare yourself
 

icy604

Passed Driver's Ed
It isnt impossible but it is highly unlikely. Prepare yourself
I assumed the worst right off the bat. I will keep this thread updated on what happens. If the valves are bent, can you recommend any particular aftermarket components? Or just stick to oem?
 

Joe_Mama

Autocross Champion
OEM parts only for stuff like this, absolutely. In fact, if that timing kit you ordered isn't an OEM kit, I would just return it unopened and get the OEM kit. the aftermarket chains are junk
 

Joe_Mama

Autocross Champion

icy604

Passed Driver's Ed
OEM parts only for stuff like this, absolutely. In fact, if that timing kit you ordered isn't an OEM kit, I would just return it unopened and get the OEM kit. the aftermarket chains are junk
I got all the timing stuff from our VW store. What about APR or IE valve springs?
 

icy604

Passed Driver's Ed
Status update: car is re-timed with a fresh chain and tensioners (balance shafts included) lucked out with no bent valves. Ended up replacing the bearing bridge, and spool valve while I was at it. Feels like a totally different car now.
 

zrickety

The Fixer
Status update: car is re-timed with a fresh chain and tensioners (balance shafts included) lucked out with no bent valves. Ended up replacing the bearing bridge, and spool valve while I was at it. Feels like a totally different car now.
Lucky dude. My thread was linked above, car was running, parked, then bent valves on startup.
 
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