C5 a6 timing belt TDC

[Jmm6730]

Here is my issue my 2.7 a6 suddenly died while driving home, after I took things apart to inspect timing belt I found that the teeth on the timing belt were peeled off by the crankshaft but my cams didn't move, so my question is how do I get this back in time since my crankshaft was moving when the cams were not, I would really appreciate any help on here I know I am new to the forum I will get some pics up later tonight thanks in advance

[brokenwrench]

ummmm......

http://www.audizine.com/forum/showthread.php/692135-2001-A6-2-7t-timing-belt-slipped-looking-for-info-on-engine-swap

Sorry, but it sounds almost like the exact same problem I ran into.

A couple questions to help narrow down the need for a rebuild:
1. How fast were you moving when the engine stopped running?
2. Did it make any clunking or banging sounds?
3. Auto or manual transmission?
4. How for out of phase are the cams in relation to the crank?

[Jmm6730]

ummmm......

http://www.audizine.com/forum/showthread.php/692135-2001-A6-2-7t-timing-belt-slipped-looking-for-info-on-engine-swap

Sorry, but it sounds almost like the exact same problem I ran into.

A couple questions to help narrow down the need for a rebuild:
1. How fast were you moving when the engine stopped running?
2. Did it make any clunking or banging sounds?
3. Auto or manual transmission?
4. How for out of phase are the cams in relation to the crank?

1. Very slow proll 10-15 mph
2. No bad noises the engine just died
3. Auto trans
4. I would say about a 1/4 turn on the crank, though I can be 100% certain

The crank has marks to line up for TDC and the cams are TDC with the large holes pointing in to the center so I was going to assume this is correct back in time just wanted to ask some other people with Audi knowledge, I appreciate all assistance, I might be thinking positive but I really don't think the motor is toast maybe I'm wrong but I'm going to put a new timing belt on regardless

- - - Updated - - -

Can't be 100% certain

[mr_dave]

The only way to set there timing properly is to install a crank lock pin and a cam lock bar and then follow the timing procedure. Lining up marks is an estimate at best.

However, I'd be pretty concerned about what happened to your belt pointing to a potentially serious problem. Any idea what caused the engine to stall? And what caused the belt teeth to shear off?

[Nemesis2747]

^ locking pin and cam lock bar. And everything he said. What happened to kill your engine like that?

[brokenwrench]

The trick, as I see it, will be to move the crank back to TDC while also moving the cams back at the same time. It's imperative you don't allow the crank to move without also moving the cams - at least one cylinder will most likely have the valves open. I would pull off the valve covers, verify the timing sequence against the extra 1/4 turn of the crank, if everything looks like it's correct, turn the crank back the 1/4 turn, install a new timing belt temporarily to allow the crank to pull the cams with it, then set the crank to TDC, remove the timing belt again, follow the remaining timing procedure. It's not going to be easy, so plan on taking your time. This process may involve measuring angles of the crank & cams to make sure you matched the correct teeth, as I understand the process, the belt can be a tooth or two off and still be ok (someone please confirm if that's correct).

But first pull all your plugs and try to look inside the cylinders, you can get a fairly inexpensive borescope (here, but others available: https://www.amazon.com/Vividia-Portable-Digital-Flexible-Inspection/dp/B00AIFSSUG/ref=sr_1_4?ie=UTF8&qid=1478095004&sr=8-4&keywords=flexible+camera) while you're turning the crank back to TDC. You can verify the position of the cylinders against the cams to see which valves are open/opening and compare to the corresponding pistons.

Also pulling off your valve covers might help find out why the timing belt sheared teeth in the first place (seized cam?).


Good luck

[rollerton]

You bent valves. Absolutely 100%, no questions, it sucks but noone in the world is that lucky. Just the compression of a couple cylinders is enough to move the crank enough to bend valves if your belt stripped some teeth.
IF the engine started misfiring but didn't die suddenly I'd say you have a fighting chance. But if it dies no warning while you're moving..yeah. Bad news.
It happens.
Anything is possible, but I'll toss some money down on 12 bent valves.

[Jmm6730]

The engine did start to hesitate before dying, i have a Bentley manual and it doesn't really have a process for putting crank and cams back at TDC

[Nemesis2747]

The engine did start to hesitate before dying, i have a Bentley manual and it doesn't really have a process for putting crank and cams back at TDC

You could open the valve cover and see the markings on the cams and measure 16 links in between. There are pics of this. For every 2 turns on the crank the cams spin once. At correct TDC cylinder #3 is at top dead center. I dont know how you are going to do that without removing cylinder heads or maybe bending more valves. Broken wrench's idea works for me. Open the valve covers and check which valves the lobes are opening while peeking through your spark plugs to watch the pistons. But yea that's going to take a while.

[Bigglezworth]

The engine did start to hesitate before dying, i have a Bentley manual and it doesn't really have a process for putting crank and cams back at TDCThis is simple. Crank pin locks the crank at TDC. Cam bar locks cams in place. Put on timing belt, set tensioner, and voila. If any of this is Greek to you, you probably shouldn't be performing the work yourself.


You could open the valve cover and see the markings on the cams and measure 16 links in between. There are pics of this. For every 2 turns on the crank the cams spin once. At correct TDC cylinder #3 is at top dead center. I dont know how you are going to do that without removing cylinder heads or maybe bending more valves. Broken wrench's idea works for me. Open the valve covers and check which valves the lobes are opening while peeking through your spark plugs to watch the pistons. But yea that's going to take a while.What you are citing is only for direct cam timing of cam tensioner. It has zero to do with timing belt matters.

Proper instructions are included with every timing belt kit made for this engine.

[julex]

Move the crank shaft to non-interference zone and then you can spin the cams to your hart's desire. Once you set the camshafts at "ZERO" with either lock bar (good enough estimate, bar is not THAT accurate) or to timing marks on cams and bearing caps (this is the true indication of proper cam timing), move the crank clockwise to TDC.

What's an non-interfence zone? A position of crankshaft where none of the cylinders are at TDC and valves have room to go up-down without hitting any pistons. It is designated on timing belt sprocket cover with a large cutout at around 10pm in orientation to where timing arrow is.

If you look at this picture, it shows alignment of timing tick to timing arrow on the cover, this is TDC. If you place the tick inside of the larger cutout which is at around 10pm (so move counter clockwise) in respect to timing arrow, you will be within non-interference zone.

http://pictureposter.audiworld.com/2021/20.1.jpg