Timing Jumped - Repair/Sell Advice Please

[Sedge]

Hi All,

 

I am new here and its because my 2008 A3 2.0 Petrol DSG Quattro has died and i could do with some advice please.

Hopefully someone can give me advice on the best course of action or can possibly suggest a garage/person who is a specialist in these cars/engines and can repair it or also give me advice. This is a long post but only because I'm trying to explain as best as I can what has happened and try to give as much info as possible.

 

To begin with I have had a mechanic take a look and we have determined the timing has jumped. When it is cranked over by hand the pistons move up and down but the valves aren't moving at all and the engine wont turn over for a complete 360 degrees. We can see this as I have a camera for looking through the spark plug holes.

I don't believe the timing jumped when I was driving it as I heard/felt nothing and just parked up - it was only evident there was a problem when I came to start it a few hours later and it would only turn over. Due to this I am hoping the damage is minimal but I am no expert.

With the mechanic we have taken a look through the spark plug holes to try and determine just how much damage has been done. I have attached a couple of photos and linked a video (below) which he believes shows a slight bit of damage to the piston heads (the gold coloured areas) and therefore means the valves have struck the pistons and more than likely have damaged/bent them. 

 

I do know this mechanic quite well so don't believe he is taking me for a ride but he has quoted me £1500 worst case scenario. That is essentially to remove the head, replace all the valves, new head gasket, level the head (this one i am not sure about), new timing kit plus all ancillary parts which goes with it. With the majority of the cost coming in the form of labour unfortunately.  Do you think this is all needed to be done, is it over the top or more needs to be done, with the explanation, pictures and videos i have provided? Is there anything else we might have missed or misdiagnosed?

 

I am very keen to fix it but I am also open to the idea of selling it as is for someone else to fix and sell/use but I am not sure what kind of price to be looking for - is this something anyone can also advise on please??

Any help and advice is much appreciated and hopefully I won't have to end up scrapping it as it is a real nice car to drive and I don't want to give up on my pride and joy.

 

Video: https://www.dropbox.com/s/m1dxk35b28870fr/Untitled%20Project.mp4?dl=0 (the video should be open to all and not need a dropbox account to view)

 

Thank you

 

Sedge.

[cliffcoggin]

James.

Thanks for detailed description. It is rare for such a full explanation to be provided for us to work with.

I don't believe the price you have been given is unreasonable for the work your mechanic has suggested. The damage to the pistons seems minor and you can probably get away without changing them. If you are really lucky the head will not have been bent and the job will be cheaper, but you won't know until the head is off.

What you need to be aware of is the possibility of damage to the conrods. It's only a small possibility if the failure occurred at cranking speed; if it had happened while the engine was running the chances of conrod damage would be far greater and might require a complete engine rebuild.

This is a classic example of the damage that happens when timing belts are not renewed in time. Belts, unlike chains, give little warning of imminent failure, hence the need to renew them according to the manufacturer's schedule.

Do please let us know the outcome.

[Sedge]

1 hour ago, cliffcoggin said:

James.

Thanks for detailed description. It is rare for such a full explanation to be provided for us to work with.

I don't believe the price you have been given is unreasonable for the work your mechanic has suggested. The damage to the pistons seems minor and you can probably get away without changing them. If you are really lucky the head will not have been bent and the job will be cheaper, but you won't know until the head is off.

What you need to be aware of is the possibility of damage to the conrods. It's only a small possibility if the failure occurred at cranking speed; if it had happened while the engine was running the chances of conrod damage would be far greater and might require a complete engine rebuild.

This is a classic example of the damage that happens when timing belts are not renewed in time. Belts, unlike chains, give little warning of imminent failure, hence the need to renew them according to the manufacturer's schedule.

Do please let us know the outcome.

Many thanks for getting back to me to quickly

A couple of questions as I'm a bit of a noob with engines....

You mention I might be lucky and the head won't be bent. By this do you mean the valves might not be bent or something else to do with the head? 

Also for my own knowledge and for further reference... Should I have had my timing chain changed for similar reasons as belts get changed at certain milage amounts? My car has done around 90k but as it didn't have a belt it never crossed my mind, honestly. Maybe i could have prevented this with hindsight.

Cheers again!

[cliffcoggin]

Your mechanic has rightly assumed the valve stems will be bent and will have to be renewed. He has also estimated for flattening the head which may no longer be flat enough to seal against the block. Flattening ( or levelling in your words) involves setting the head on a large milling machine and cutting as much metal off as is necessary to achieve a dead flat surface, usually in the region of 10 to 20 thousandths of an inch. It's a problem more often associated with an over heating engine.

I don't know the details of your engine but it must have a belt, a chain, or gears to drive the camshaft. Gears have been out of favour for decades, and chains are rare nowadays, so I assume it has a belt. Check your service schedule in the handbook to find out exactly what should have been done and when. Your service history will show if the scheduled work has been done.

[Sedge]

40 minutes ago, cliffcoggin said:

Your mechanic has rightly assumed the valve stems will be bent and will have to be renewed. He has also estimated for flattening the head which may no longer be flat enough to seal against the block. Flattening ( or levelling in your words) involves setting the head on a large milling machine and cutting as much metal off as is necessary to achieve a dead flat surface, usually in the region of 10 to 20 thousandths of an inch. It's a problem more often associated with an over heating engine.

I don't know the details of your engine but it must have a belt, a chain, or gears to drive the camshaft. Gears have been out of favour for decades, and chains are rare nowadays, so I assume it has a belt. Check your service schedule in the handbook to find out exactly what should have been done and when. Your service history will show if the scheduled work has been done.

Ahhhh I understand now. Thank you for clarifying.

My engine is a timing chain as opposed to a belt. At first I was hoping the timing had just jumped and there'd be no damage before I looked with a camera but doesn't seem the case 

Edited October 18, 2022 by Sedge

[cliffcoggin]

Timing chains rely on a tensioner to prevent the chain jumping a sprocket tooth so I expect yours is worn out, however as the tensioner pad slowly wears it usually leads to a lot of noise which is the warning I mentioned earlier. Did you have any such noise before the chain failed? I believe the tensioners on Audi engines are hydraulic so there may be a problem with its oil supply in addition to wear of the pad that bears on the chain.

[Magnet]

Hello James,

Cliff has boxed this up, and there’s little to add except perhaps:- 

Economics of spending c£1,500 on a 14 year old car? Pre-Covid - probably not, but since cars have significantly increased in price since, then possibly not. Of course James, you will know its general condition and its worth-to-you.

I don’t think there are many vehicles with non-interference engines these days.

Even at a slow tick over of 600 rpm, an engine will have rotated 10 times in 1 second - so no chance of avoiding damage. 
 
100k lifespan on a chain would be reasonable, but 14 years of relatively high degree of stops and starts, puts a fair strain on chains and tensioners, so I too would be asking Cliff’s question about any evidence of chain rattle on start up in recent times -? 
Good luck, and kind regards,

Gareth. 

[Sedge]

1 hour ago, cliffcoggin said:

Timing chains rely on a tensioner to prevent the chain jumping a sprocket tooth so I expect yours is worn out, however as the tensioner pad slowly wears it usually leads to a lot of noise which is the warning I mentioned earlier. Did you have any such noise before the chain failed? I believe the tensioners on Audi engines are hydraulic so there may be a problem with its oil supply in addition to wear of the pad that bears on the chain.

There was no noise or anything I noticed before hand which surprised me. Thanks for the reply! 

[Sedge]

54 minutes ago, Magnet said:

Hello James,

Cliff has boxed this up, and there’s little to add except perhaps:- 

Economics of spending c£1,500 on a 14 year old car? Pre-Covid - probably not, but since cars have significantly increased in price since, then possibly not. Of course James, you will know its general condition and its worth-to-you.

I don’t think there are many vehicles with non-interference engines these days.

Even at a slow tick over of 600 rpm, an engine will have rotated 10 times in 1 second - so no chance of avoiding damage. 
 
100k lifespan on a chain would be reasonable, but 14 years of relatively high degree of stops and starts, puts a fair strain on chains and tensioners, so I too would be asking Cliff’s question about any evidence of chain rattle on start up in recent times -? 
Good luck, and kind regards,

Gareth. 

Hi Gareth. Thanks for your thoughts. 

The economics of doing the repair have been playing on my mind a lot and I'm still not 100% sure. It seems the combination of A38P, 2L petrol, dsg and quattro are fairly rare so I think there is still value in it and worth the repair. As the other option would be scrap for peanuts or sell broken and then I think the value will be minimum too. 

Maybe the combo is rare because this happens to them and they're not fixed though..... 

[Magnet]

As I say James, the economics is really based on your circumstances, the car’s overall condition,  and its ‘worth-to-you’. You may need to temper this with the hassle factor of repairing, and the (perhaps surprising in relation to purchase price) price the car may realise as-is, in say an eBay sale.

Sounds like you will need to give this a few coats of thinking about. 
Good luck with whatever you decide.

Kind regards,

Gareth.m