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Is this valves hitting after timing belt change

Is this valves hitting after timing belt change

 
Old 09-24-2015, 07:02 AM
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Default Is this valves hitting after timing belt change

Hey guys. First post.

I'm working on my Sons 2000 A6 4.2. He took it apart 3 years ago for a timing belt change. At this time I do not know the reason. But I will ask him. I know the car did run. So for what ever reason he never finished. Now I am doing it.

He used the proper crank pin and cam locking bar. Installed new belt at the time. But that's as far as it went.

Following the instructions I set the tensioner by using the drill bit. I torqued the cam pulley bolts, but they were all ready torqued. I could be wrong, but I'm not sure if he took off the pulleys. IDK for sure. I then took off the cam bar.

Here's where I messed up a little. I took the crank pin out and put the plug back in. Then I read in the instruction to turn the motor over 2 turns and put the crank pin back in. So I redo all that. When I do that I here a strange noise as I'm cranking the motor by hand. It sounds like a valve spring slamming closed. I don't know what it is. I hope its not valves hitting. It does it on both sides every 180*. I am hoping it could just be lack of lubrication from sitting for 3 years. It does not feel like anything is hitting when I crank it. I just hear something in the top end.

Here's what has me worried. It says to put the cam bar back on. Well it wasn't exactly lined up perfect. Meaning it didn't just slip right in place. But if I used just a little force I could get it to go on. In doing this I felt something give a little allowing me to then get the cam bar lined up perfectly. I could only guess this would be a cam sprocket spinning. I rechecked the torque and it was on the money. I did give it just a little extra in case torque wrench was off.

So can you guys watch this video and tell me if this is a disaster waiting to happen. Or could it be just lack of lubrication from sitting. In the video I am working the ratchet back and forth to show that the noise is in the same place.

Please advise. Thanks

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Old 09-29-2015, 02:39 PM
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Wow. I have 100 views and not 1 opinion.

Any of this sound remotely familiar.
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Old 10-01-2015, 10:03 PM
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Originally Posted by Quick Cal View Post
Wow. I have 100 views and not 1 opinion.

Any of this sound remotely familiar.
Yes, It sounds like the valves slamming shut.

Because there is no engine oil pressure, the cam chain tensioners are not taking up the slack on the cam chain, so when you pop over a cam lob, the valves slap shut.

so long as you can turn it over freely like you are doing all should be good.


sorry but speaking from 2.8 v6 experience, on this 4.2 v8 board looking for something else.
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Old 10-02-2015, 01:42 AM
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Originally Posted by bydand View Post
Yes, It sounds like the valves slamming shut.

Because there is no engine oil pressure, the cam chain tensioners are not taking up the slack on the cam chain, so when you pop over a cam lob, the valves slap shut.

so long as you can turn it over freely like you are doing all should be good.


sorry but speaking from 2.8 v6 experience, on this 4.2 v8 board looking for something else.

Thank you very much.
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Old 10-29-2015, 09:22 PM
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no hold on thats the front cam adjuster chain jumping, i have spent the last 2 weeks taking my cams off and plugs and doing the cam chain timing and with mis info, what it looks like happened is the steps you or son did missed the part about leave cam sprocket loose with crank plug in by the way make sure you rock engine back and forth to get pin seated i made that mistake the first time, then pull the pin and ease the timing belt adjuster then add 11lbs of tourqe to adjuster then tighten the cam sprockets to 55nm or 41 lbs with the lock bar on during all this. then 2 turns of crank = 1 full cam sprocket turn, know if you dont have cam sprockets loose you will turn the engine by hand and it will force the chaine to jump since there is no psi from oil in the cam adjusters and its just spring tension pushing them apart.
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Old 10-29-2015, 09:25 PM
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Originally Posted by Quick Cal View Post
Thank you very much.
but take the spark plugs out that will take all the pressure out of the turns and help you with identifying the noise,
i do have a 2.7t but am also helping bently publications update the service book for the a6 with tq and steps for timing that are missing
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Old 06-19-2018, 09:38 PM
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Originally Posted by bydand View Post
Yes, It sounds like the valves slamming shut.

Because there is no engine oil pressure, the cam chain tensioners are not taking up the slack on the cam chain, so when you pop over a cam lob, the valves slap shut.

so long as you can turn it over freely like you are doing all should be good.


sorry but speaking from 2.8 v6 experience, on this 4.2 v8 board looking for something else.
Can u message me if you're experienced with the 2.8 v6 im having issues with mine after a water pump and thermostat change (crank wont turn!)
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Old 06-25-2018, 07:57 AM
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Makodrifts 115, Just seen this. Note down what you have done on the engine 2.8 30V forum board.
I and a couple of thousand other people have experience and are willing to help.

cheers
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