Timing my B8 - Popping noise

[edadelman]

I have my 2.0TFSI engine pulled from my 2009 A4. I installed new timing and balance shaft chains, guides, tensioners and a cam bridge. Everything seems lined up and I’ve checked and rechecked timing after turning the engine by hand a number of times. It all seems fine and all measurements are correct.

When I am turning the engine over by hand I hear a popping sound about every half rotation. Like a valve or something is opening up. Truly sounds like an air popping noise. It doesn’t sound like metal tapping but I want to make sure this sound is normal before I put it back in the car. Does anyone know what I might be hearing?

[Allowencer]

Do you have the rockers flipped?

Intake rockers are different from exhaust rockers

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[Theiceman]

i have also heard issues with the phaser unit on the intake cam cause this,popping out of its detent. The problem is we don't really know what its supposed to be like without oil. but i would get a buddy if necessary to listen real carefully while you turn before putting it all back together.

[edadelman]

Do you have the rockers flipped?

Intake rockers are different from exhaust rockers

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Did not touch the rockers. Just did the timing and balance shaft chains.
Have not touched the rockers. Just did the timing and balance shaft chains.

[edadelman]

i have also heard issues with the phaser unit on the intake cam cause this,popping out of its detent. The problem is we don't really know what its supposed to be like without oil. but i would get a buddy if necessary to listen real carefully while you turn before putting it all back together.

I am going down this same line of thought. The oil is drained. Maybe I should fill it while it is on the stand and listen again?

[Allowencer]

Good to know rockers weren't touched. It more than likely is the intake cam adjuster, but that's concerning if it pops out of the parking position. That is what eventually led to the failure if my intake cam.

Some noises will be heard on the valve train naturally as you aren't freely spinning the engine. Each time you push down, applying torque, everything in the timing circuit will feel that torque too. This only happens on initial starter engagement and then it's a consistent rotation. If you can try to consistently rotate without stopping, you might not hear those noises.

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[Theiceman]

I am going down this same line of thought. The oil is drained. Maybe I should fill it while it is on the stand and listen again?

no as this normally runs with oil pressure, that will do nothing more than make a horrific mess lol.

[edadelman]

Good to know rockers weren't touched. It more than likely is the intake cam adjuster, but that's concerning if it pops out of the parking position. That is what eventually led to the failure if my intake cam.

Some noises will be heard on the valve train naturally as you aren't freely spinning the engine. Each time you push down, applying torque, everything in the timing circuit will feel that torque too. This only happens on initial starter engagement and then it's a consistent rotation. If you can try to consistently rotate without stopping, you might not hear those noises.

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Is there a way for me to verify the intake cam adjuster coming out of the parking position? Can you see this?

[Allowencer]

Is there a way for me to verify the intake cam adjuster coming out of the parking position? Can you see this?

You would have to take it apart and look at the cover of the stator. Be careful if you do, there's a spring and pin that will shoot out as that is what locks it into "starting" position.

Here's pics of mine when it broke

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[Allowencer]

I found the broken cam, here's a better picture. The pin attempts to lock into the back face of the stator. Overtime it wears down the hole and it is now a ramp where it can easily slide out

The little wiggle channel is where oil flows and builds pressure to push on the face of the pin to unlock the parking position. ~6-7 PSI is all that is needed. By then there's enough oil pressure within the vanes of the actuator to where it can be controlled and adjusted by the computer.

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[edadelman]

I’m starting to think these might be normal noises related to the valves opening and closing and that maybe I am just a bit paranoid. I put a lawn flag in each cylinder as that is where the noise seems to be coming from. Mostly I think the number one cylinder but for sure also seems like it is in the others. As I bar the engine over it does it at almost but not quite the top of the up stroke and pretty close to the bottom of the down stroke.

One more thing. This engine never jumped time and I never got any camshaft or timing related codes. It needed a new rear main seal so I pulled the engine to do that and did all the chains and a new water pump while I had it out. Compression was fine before I pulled the motor so I don’t think I have bent anything.

[Theiceman]

sounds like you Re good to go if you did all the timing correctly

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[CO-Alrd]

What did you end doing here? I just torqued the crank bolt and when I rotate by hand, I also hear a popping sound that I don't remember hearing when I took everything apart. I am certain that my timing is correct as I checked it countless times and again after bolting the pulley on with the upper timing cover removed. My nerves are getting to me here so I'm hoping you didn't have any issues after your timing job!

[Allowencer]

The popping sound comes from the intake cam and it's once every rotation due to valve springs and valve train pushing back on the camshaft. This causes the cam actuator to bounce a bit and make a popping noise. Once oil is all filled into everything, it minimizes that noise.

If you were to put the engine together, prime it with oil for pressure and then manually spin it (without the plugs in), that noise shouldn't be present anymore.

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[RPMtech147]

A little popping noise has been normal when rotating a fresh timing set in my experience.

[CO-Alrd]

That makes me feel much more confident to bolt the front end back on and complete this job! The thought of toasting the valvetrain in a car is not a pleasant thought so I appreciate the responses.

[CO-Alrd]

That makes me feel much more confident to bolt the front end on and get the job over with. The thought of having to pull the front end and do the timing job plus a valve job has made me extra cautious as I've only had the car for two weeks and decided not to drive it at all until the timing job was done. -6.5 degrees and about 7 grooves exposed on the tensioner so it was definitely time!

[Allowencer]

Ensure you measure the timing marks to know if you are really on time too.20230617_162045.jpg20230617_162100.jpg

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[CO-Alrd]

So I wrapped up the timing job about a month ago and all is well. I will say that the instruction in the service manual are not super precise with the visual guide for caliper location but the caliper arm should be on the opposite side of the cam bridge tab in your photo. I measured to the next link on the chain to see how far I'd be off if I got it wrong and it was very obvious. I still measured 20 times with two different calipers to be sure!

[Allowencer]

True, outer edge is the real proper way. The spec is 61-64mm for that measurement. You measure to the camshaft's mark on the sprocket though, not the chain's link.

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