Saving an ATL 90 with a broken balancer chain - part 1/3

H

heppers

Member
Some of you may remember that I posted a request for help in June 2017 for a 2005 TDi 90 that had decided to throw a balancer chain...

Well there's a long story (with a happy ending) that I thought I'd document. Starting with the suggestion to drop the engine through the front on a warm sunny day in July 2017.

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... and then admire the thick layer of diesel that had dribbled all over the tandem pump and front corner of the block from the fuel pipes...

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... before stripping the turbo for sending off to Turbo Dynamics for refurbish...

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... showing the thick layer of carbon deposits throughout the manifolds (both inlet and outlet) that was the result of worn seals.

... before we start on the head by removing the timing chain...

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... with essential kit including timing belt locks and M6-M14 spline sockets.

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The eventual seizure culprit was uncovered, and the damage was more extensive than originally thought...

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... note the eccentric position as the sprocket was relocated around the crank against three flats.

Then the removal became "interesting" with a drill and shear approach to removing the now welded-on sprocket...

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... but the cleanup left a suitable home for a second-hand sprocket from WOM Automotive (many thanks Rob!)...

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... and a home-made tool using the original crank bolt was fashioned from a hole cutter...

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... which slid the 250 degree heated replacement beautifully into it's new home...

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... part 2 to follow as I can't add more pictures.
 
With head removed the de-coke continued from this...

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... to this ...

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... and the block had a de-grease and grind down of rust and re-paint from this...
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... to this...

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... and the balance shaft was re-fitted ...

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... with a fully renewed oil pump and balancer shaft chain ...

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... just in time for the reconditioned head from Park Engineering in Malton who did a lovely job...

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... and then it was time to reassemble with new timing belt, water pump, thermostat and tensioner (£150 whilst it was open) ...

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... and then re-install of the inlet manifolds after a good clean...

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... part 3 to follow ...
 
... the DMF was in good working order, so installed with a new clutch ...

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... and the gearbox had a good clean in degreaser and new input seals, final drive seals and release bearing ...

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... the Turbo took a long while to return (Zircotec who were ceramic coating it had an industrial fire) but the result was stunning ...

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... and it reinstalled on new studs beautifully ...

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... before completing with that lovely EGR system ...

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... and the best bit was reinstalling in the car last weekend and having it start first time with no leaks ...

I'll post final photos once the MOT has been granted and report on how that refurbished turbo runs, but early indications are that the exhaust is totally cured of blue smoke and my beloved A2 is headed back to a life of service.

Thanks to all those on this forum for their help and encouragement.
 
Well done, very interesting, but I would have deleted the egr!

Sent from my SM-N960F using Tapatalk
 
Olerype said:
Amazing!

May I ask how many miles has the engine?
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It had only managed 77,500 miles - about 6,500 miles per year.

I think part of the problem had been a single tooth that snapped off the balancer shaft sprocket and got trapped in the works damaging the chain at some point (there was two points of damage to the chain, and I found the tooth in the sump looking all innocent - it's the one in the middle). The damage to the crank sprocket was all instantaneous when the engine came to a halt, so no damage beyond the seizure thankfully - all the other teeth and mangled chain carrier were found next to the crank sprocket. The oil pump was replaced just out of precaution - once it was stripped and cleaned it looked as good as new.

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I think the main culprit was leaving the engine on Audi variable servicing which meant an oil change every 18,000 miles (2 years). This destroyed the turbo oil seals, and resulted in a lot of oil passing through the intercooler and very tired valve stem seals. Audi were getting very insistent to switch back to annual servicing from about 2012 onwards and I now understand why as these diesels appear to suffer badly from aged oil.

I'll be servicing (oil and filter change) every 5,000 miles from now on.
 
Jellybean said:
Well done, very interesting, but I would have deleted the egr!

Sent from my SM-N960F using Tapatalk
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I did think about deleting the EGR, but do like the speed with which the car can generate heat for the windscreen in winter - so went instead for the ceramic coating - it's supposed to raise the exhaust temperature by around 30 degrees making both the turbo and heater matrix more efficient, and should reduce the propensity for recycling unburnt rubbish back into the inlet - I'll report back on findings once we have travelled a few thousand miles.

;)
 
Totally agree with you about service. I service mine once a year or every 15000km (9300miles). Have seens various oil analysis and the oil detoriation starts at about 8-10000km and really downhill from 12-15000km. That was for VAG diesels with DPF so worse for oil than ours, but still a good thumb rule.
 
heppers said:
I did think about deleting the EGR, but do like the speed with which the car can generate heat for the windscreen in winter - so went instead for the ceramic coating - it's supposed to raise the exhaust temperature by around 30 degrees making both the turbo and heater matrix more efficient, and should reduce the propensity for recycling unburnt rubbish back into the inlet - I'll report back on findings once we have travelled a few thousand miles.

;)
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Deleting EGR can increase NOx emissions by up to 40x, or 4,000%, as well as being illegal:

www.newscientist.com

Nitrogen oxides in car exhaust kill tens of thousands in UK

Evidence is mounting that NOx emissions don't just make us ill by boosting the production of ozone and tiny particles – they directly damage our health too
www.newscientist.com www.newscientist.com

www.theguardian.com

38,000 people a year die early because of diesel emissions testing failures

Global inventory of nitrogen oxide emissions shows highly polluting diesel cars are ‘urgent public health issue’
www.theguardian.com www.theguardian.com

RAB
 
RAB said:
Deleting EGR can increase NOx emissions by up to 40x, or 4,000%, as well as being illegal:

RAB
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Thanks RAB, like I said... I "thought" about it based upon what has been posted on here before and then decided against it - instead spending £450 on the ceramic coating to get an option that I _hope_ will be better than original equipment by using modern technology to increase the performance of the combined manifold/turbo and EGR. If I'm scraping out carbon deposits from the EGR valve and inlet in 3 years time, I'll know my idea failed.

:oops:
 
heppers said:
Thanks RAB, like I said... I "thought" about it based upon what has been posted on here before and then decided against it - instead spending £450 on the ceramic coating to get an option that I _hope_ will be better than original equipment by using modern technology to increase the performance of the combined manifold/turbo and EGR. If I'm scraping out carbon deposits from the EGR valve and inlet in 3 years time, I'll know my idea failed.

:oops:
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After three years you will probably need to attend to/clean the VNT mechanism anyway, so it's just something else that you have to remove in the process and clean. Not a big deal really.

RAB
 
A lovely job and write up @heppers

@RAB my ATL 90 is fifteen years old, 170k miles; the original VNT has never been cleaned, apart from by using my right foot and driving “like I have stolen it” when the opportunity presents.

I have a couple of usually quiet dual carriageways on regular journeys where uphill inclines take 3 to 4 minutes at 70mph. Foot to the floor in 3rd, revving well into red, the car tops at just over 70.

When I bought it in 2009 it had a known issue of going into limp mode, especially on such long inclines. My service garage, Audi Doctor in Stockport, checked out everything and advised me to use premium fuel, and to drive it this way. The limp mode issue has gone away, and I am now back to using cheap diesel fuel, with the occasional full tank of Shell V-Power diesel.

I have written this in the forum previously; it is repeated here because most of the advice I found on the forum back then was interventionist. Hopefully it will help other ATL owners avoiding spending unnecessary money.

Andrew
 
andrewparkeruk said:
A lovely job and write up @heppers

@RAB my ATL 90 is fifteen years old, 170k miles; the original VNT has never been cleaned, apart from by using my right foot and driving “like I have stolen it” when the opportunity presents.

I have a couple of usually quiet dual carriageways on regular journeys where uphill inclines take 3 to 4 minutes at 70mph. Foot to the floor in 3rd, revving well into red, the car tops at just over 70.

When I bought it in 2009 it had a known issue of going into limp mode, especially on such long inclines. My service garage, Audi Doctor in Stockport, checked out everything and advised me to use premium fuel, and to drive it this way. The limp mode issue has gone away, and I am now back to using cheap diesel fuel, with the occasional full tank of Shell V-Power diesel.

I have written this in the forum previously; it is repeated here because most of the advice I found on the forum back then was interventionist. Hopefully it will help other ATL owners avoiding spending unnecessary money.

Andrew
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Hi my ATL 90 is also on 170k miles,As far as I know it's on its original VNT which looks like it's never been off the car.It spools like it should with no limp mode so far.Like all cars you get some bad luck from time to time
 
Great job nicely done! Just out of curiosity, approx how much this job would've cost at the garage, if you didn't do this yourself? Also can petrol ones suffer the same from not changing oil in time? Thanks
 
Sylvester said:
Great job nicely done! Just out of curiosity, approx how much this job would've cost at the garage, if you didn't do this yourself? Also can petrol ones suffer the same from not changing oil in time? Thanks
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A rough breakdown:
  • Head refurbishment (valve and seat regrind, skim, bearings, gaskets and seals): £250+VAT
  • Turbo refurbishment (compressor wheel and bearings): £250+VAT
  • Manifold Ceramic Coating (combined manifold and turbo): £450+VAT
  • Timing Belt, Oil Pump, Tensioner, Water Pump, Air Filter, Oil Filter and various seals / bolts: £800+VAT
  • Balancer Chain Set (all four sprockets - NLA) : £260 + VAT
  • Fluids (LL oil, G13 inhibitor): £85
  • and about 72 hours of my time (but I don't rush things so probably 45-50 hours for a garage)
... so £2,500 in parts plus whatever you pay for labour. It was still less than half the £8,400 Audi quoted me for a new engine...

This wasn't about the cost though. I wanted a car that would give me another 100K+ of miles of rust free motoring without ending up as landfill.

As others have said, changing oil every 8-10,000 miles saves big bills, but the petrol cars don't have the balancer chain or turbo that are particularly vulnerable to aged oil.
 
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