Timing Belt Change - DIY Cam locking tool - Page 2 - AudiForums.com


Audi A6 The mid-sized Audi A6 model offers more room to the driver and passengers over the A4 line.

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  #11  
Old 07-13-2013, 01:27 PM
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Default Timing belt update

My method of locking the cams caused some discussion.

I would like to update this thread and say it's been more than a year since I changed this timing belt. Car has been driven pretty much every day by my 16 year old daughter who is not "light' on the throttle.

Still runs like a watch.
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  #12  
Old 07-13-2013, 01:28 PM
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Join Date: Mar 2012
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Default Timing belt update

My method of locking the cams caused some discussion.

I would like to update this thread and say it's been more than a year since I changed this timing belt. Car has been driven pretty much every day by my 16 year old daughter who is not "light' on the throttle.

Engine still runs like a watch.
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  #13  
Old 10-13-2016, 11:22 AM
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I do not normally post but when I happened to see this I couldn't resist. This is NOT an acceptable method of locking the CAMSHAFTS for timing belt replacement. You have the cam pulleys locked (sort of) not the camshafts. The cam pulley bolts need to be loosened and the cam pulleys "cracked" free from the cams. The pulleys need to spin freely. The pulleys lock to the camshafts by an interference taper fit so they can freewheel when you install a new belt and set tension. If you do it like you did, the timing belt will not tension correctly and the timing cannot be precisely set. PERIOD!!! If your cars still running, great. But is it running as great as it could be? I would say you dodged a bullet. One tooth off will cause tons of timing issues. For people looking into doing this job, please DO NOT use this approach. You are asking for a disaster.
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  #14  
Old 10-14-2016, 02:23 PM
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Default Theory and practice

It's been about 4 years since I changed the timing belt on that A6. It's about ready for a new one, still runs like a watch.

I have a degree in Mechanical Engineering from a top 10 University (lots of theory). I have spent 30 years building all manner of cool cars, my specialty is high performance motors (lots of practice). Theory and practice are different.

It's correct that the "proper" way to set the timing on these engines is to free wheel the cam sprockets. In theory it's better. One of the things I like about these German designs is their over the top fussiness. So many things are over thought and over designed. It's what I like most about these cars. They are a pleasure to work on.

In practice, I don't think the tiny difference matters much (do some math and think about it). So many of the motors I work on now have variable cam timing, it's easy to see the effect of relative timing on performance. When you are the dyno you can see how varying the cam timing changes the power. In the macro, having variable timing is terrific. In the micro, over the RPM range a degree or so, it's not so much. That's my opinion, yours can be different.

BTW, I did another one of these a couple of years ago (changed timing belt) and borrowed a cam locking tool just to see the difference. The difference between these methods was not perceptible to me. I marked where the sprockets were relative to the cams before and after setting the tension. They didn't move perceptibly. Theory and practice. YMMV.
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