S8 d3 v10 2007 engine torque settings
 

Hi all, Could anybody tell me where to find torque settings and sequence for bolts of the V10. I have striped the engine down to replace number 8 piston which has broken and I am trying to get all the information I need to reassemble while waiting for the delivery. I have tried web searching and found details on every other engine but the V10 seems not to exist. I could do with figures for the head, sump, crank guard, lower block and gearbox. Thankyou

Here you go,
http://forum.a8parts.co.uk/attachmen...1&d=1420367102
http://forum.a8parts.co.uk/attachmen...1&d=1420367344
http://forum.a8parts.co.uk/attachmen...4&d=1420367344



Would love to see photo's of the process, the more the better, engine bay, stripped engine etc

Bloomin' Heck Del, You beat me to it :D
I was just checking for the link, came back to put it in and there you were.
I love this forum.

auds8tui
As this appears to be your first post may I welcome you on board?

Wow that was quick, thankyou very much gents. I will download the pictures off my camera tonight and put on here. I am still puzzled as to how the piston had a part knocked off. I bought the car cheap with a known knocking noise which I found out from service records has had for 2 years. The dealers had no clue. Last week I dropped the sump to check the oil pump and found two bits of piston which now the piston is out fit perfectly so at least I know there is no more bits of metal left in the block.

Wow they knew about it for two years :Confused:

Anyway result for you, I look forward to seeing your pictures, I too have an S8 so have a keen interest to see more of the inside the beast.

This is a mixture of removal and trip down, the last picture is the aircon compressor, wondered why it wasn't working.Attachment 12422

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In some ways i'm envious, i love pulling stuff apart and getting to know its inner workings.

What kind of mileage does it have on her and have you seen anything like wear on things like the timing chains, guides etc, camshaft lobes, big ends etc.

Just try to get an idea of the longevity for these engines

Are you going to change them o2 sensors before she goes back in, would imagine they are next to impossible to get at when its in

Oh and whats the inlet ports like, much carbon build up? and hows the change over flaps in the plenum?

Is there tell tail marks on the crank web , has the web been clipping the bottom of that piston skirt
Has the engine ingested water , has the engine had a valve to piston bash at some point

It's only done 74,000 and I cant find wear anywhere, the chains and guides are all good. Apart from the metal knocking noise the engine was fine, no smoke noise or leaks

I am not replacing anything else apart from what is broken as my thoughts are where do you stop, hoses, sensors, chains etc. I replaced the o2 sensors on my Lexus 430 while the gearbox was out and found 1 of them to be faulty after I had finished. If its not broken don't fix it.
I had removed and cleaned the inlet manifold and used the cable tie on the battery drill method for the valves. Once I split the manifold open I found it full of oil from a faulty oil separator but the flaps were all good.

I think the oil is just the way the separator works, at full throttle the blow by gasses is too much for the unit and it opens and allows the oil vapours stright through.

What is the web?
No water as far as I know and no damage to the piston top os to the cylinder wall which is a relief. No metal filings in the oil.

All I have been told is that the car involved in a high speed police chase 3 years ago after a bank job in Slough. The car ended up dumped in a field.

The knocking noise started at this point along with a broken rear gearbox mount and the front right hydro mount failed.

Sorry I should of said counter weight .....




http://i618.photobucket.com/albums/t...pszau8siu9.jpg

I've seen ' nibbled ' piston skirts where they have been clipping the counter weight .

Why would this happen ....anyone want to take a pop at it ...

Im interested to know why, is it thermal expansion from an overheated engine? closing up the clearance from skirt to crank?

Now I understand, I have looked and turned the engine by hand to find out what had happened but as the piston is aluminium and the crank cast metal there is no marks if it had caught the piston.
I am still puzzled as to why this damaged piston was making horrible metal on metal knocking noise for two years with not even a scratch in the bore

Has this happened before as I have never heard of this before. There is a sizable gap between the two parts, that would be an awful lot of expanding metal if the heat was to blame.

Good guess Del but in most cases they don't run that close normally , the clue was in my first post " has it ingested water "
Even though this may not be the issue with this engine the symptom of nibbled skirt is the same .......

Bent con rod ?? If it was stolen and had the death ragged out of it , but in most cases the rev limiter will stop that sort of damage .

So a bent rod will not reach top dead it will be short of reaching deck height , but on the downward stroke the shortened rod pulls the piston further down the bore and in some cases clipping the skirt on the crank counter weight .

It may not be this but you have to rule all of the causes

Audis8tui have you turned engine over with heads off to see if that piston in question falls short of the deck height .

Interesting but if that were true would it not be the case that a few more at least of the cylinders would suffer the same fate?

If it was just one rod that was bent then would it be fair to say that a leaking head gasket would be more likely?

If it's water ingestion usually because the water is heavy it's the first cylinders in the pathway from throttle body's , the first in the flow line scavenge all the water .
It is was cylinder 8 so I assume that is the cylinder closet to the bulkhead furthest away from the throttle body's so yes does not make sense .

I can't say I've seen bent rods from head gasket failure , in most cases the blow by channel across the gasket only lets small amounts of water in , not enough to massively flood the cylinder , suppose if i head gasket really bad it could flood it and hydra lock on start up , so yes it's a possibility .

Are these V10 s direct petrol injection ..... possible hydra lock on fuel

" A broken rear gear box mount and engine mount failed "

Could this hold a clue .........could it have had a massive ' gear down ' scenario at that revved the balls off it

That I haven't tried, my new piston will be here Wednesday and I will check that. The con rod looks good with no damage to bearing.
I do have another issue with the car which I was going to deal with after the engine is fitted, there is a misfire on start up for 4 mins on the same bank, I forget the code but it tells me low fuel pressure on all 5 cylinders.
After 4 mins all good and I can leave the car all day and it doesn't return but left over night its back.

Leak on the HP fuel pump on that bank???

If it was a fuel leak would it not leak all the time, I have no smell of fuel either. I think its more electrical, sensor or even ecu.

Mmmm ,Injector leaking badly on the damaged piston cylinder pulling the rail pressure down on that bank , cold start missfire is cylinder flooded with fuel and taking time to clear it , any signs of bore wash on that cylinder ( more wear )

Good thought, not thought of that. would it take that long though to burn it off.
All the bores look and feel identically smooth, all piston crowns look the same also.
The head gasket was also good and the valves still clean after the de coke I did 3 months ago.
If I start the car in the morning and leave to tick over for 4 mins (which I know isn't good for the engine) turn the engine off and then restart all is good.

If I start the car and drive off it can be 5 mins before all 10 are firing and with slow moving traffic the only way I know all is working is the management light stops flashing

No I wouldn't think it would take that long really , could you look at injector corrections with vcds .
The high pressure petrol pumps , do they suffer like the vauxhalls with the same systems , where they break up internally and send metal debris down to injectors...... I've never under stood how you can lubricate high pressure petrol pumps with petrol .... there's not much lubrication property's in petrol unlike a diesel high pressure pump .

I can understand the injectors or pump causing missfires and so on , but what has broke that skirt , you say it come on after the car was stolen , wonder if it just got a ragging from cold before its expanded properly and it's just rattled in the bore and broke it
Not sure ....!interesting one this

If one of the injectors was leaking badly could there be enough fuel to create hydraulic lock on the cylinder to bend the rod while the engine was starting?

I guess that will be proven when new piston arrives.

Fascinating thread. Thanks +++
I've always been able to figure why, when I've been piston broke. Hope to hear an explanation for this one sometime.
Perhaps its down to a faulty/damaged piston fitted in the first place, Maybe there's a lot of V10's with the odd piston skirt damaged, and we're unaware of it and the clicking noise was caused by something else.

Note that parts of the piston were found in the sump that fitted the damaged piston

Pistonbroke .....yeah been there hehe

Interesting one this , if it's not a bent rod or it's not running close to the crank counter weight in any way , my next best surmise would be an over revving from cold , if the cars been stolen and in a chase this could be likely and yes it could of been a manufacturing defect and it only showed its face on the one piston .....it's hard to say , we could guess at a lot of things ..

You say it misses from cold , and the codes to do with low fuel pressure on that bank ..... would you say it's like one cylinder down or more or a general unevenness to it .

Has anyone had a Diesel engine run away with its self due to say a turbo failure or sump overffull of oil ..... I've had it once on a td6 Range Rover .... it's pretty scary ...... Billowing smoke and screaming it's nuts off till it throws a rod out , makes a reet mess ......... where am I going with this .......

So in some cases with a major over Rev the high pressure diesel pump breaks up ,the case hardening comes off the rotor and metal debris is scattered around the system .....where does the metal end up ....... yes ,in the injectors , so you end up with low pressure codes due to the back spills dumping it out .... high pressure fuel systems will not tolerate metal debris what so ever , the fuel system is as good as finished , contamination in pump , injectors , fuel rails , swirl chamber in tank , metal debris all in bottom of tank due to fuel returning all the debris back there .

Could this be the reason our v10 is giving codes for one bank for low fuel pressure , if a diesel pump breaks up and that is lubricated with oil , I would say for sure a high pressure petrol pump will break up .
Perhaps it's still able to deliver fuel but not up to spec , perhaps after the car has run for 5 mins or so the cylinder balancing and contribution is ramping the pressure and duration on that bank to get it to contribute to get engine smoothness.

On the bank that has low pressure.....the high pressure pump does it have a return pipe that has a banjo bolt with a basket filter in the banjo , or any return line banjo bolts for that matter , take them out and look for metal debris .

If you need the injectors testing I have a man .....he is Martin Wainwright from Wainwright Bros. look him up on YouTube .... proper professional and will inspect the nozzles and pintles under a microscope to look for metal particles

Lots of theory's and maybes , but to do all the work you already have done there , you have got to get it checked out ..... massive waste to put it all back and it not be right .

Respect to you for taking a big job on like that , most garages just don't want this type of work ....just to long winded and if one small thing is over looked you would be pulling it all back out again .

Lee

My thoughts precisely... Well done !! :cool:+++

Missfire on those engine commonly is caused by carbon deposit build up in manifold. Having all apart get the manifold properly clean, check flaps for damage ... sorted
Decoke service is provided for all fsi engines by some specialists

Says he already done manifold decoke

Sorry missed that

Well gents the new piston arrived, fitted and put all back in and its exactly the same.
I have today removed the engine and striped it down again, I have removed all the pistons on bank 6 to 10 and found to my horror cylinder bore to number 7 is not round. It looks like the piston has been going up and down un true.
All that work on piston number 8 made no difference at all.
My question now is I am told these blocks cannot be bored out as there is 6mm between the cylinder walls and the dealers tell me they don't supply oversized pistons.
Am I looking at scrapping the engine or even the whole car as a replacement block is way over my budget.
Has anyone had this issue before or even heard of it.
I can only assume that the water cooling has been interrupted and the cylinder wall has almost warped.
With just a piston ring sliding square down the cylinder wall there is a gap of 20 thou where the wall is warped.
Help

Oh Bugger, enough to make your eyes water.
I feel for you.
Wishing you the best of luck with it from here on, hopefully it will come right. But an off round cylinder, wow :mad:

Wow !! did you check that the all the pistons come up to top dead and have clearance between crank weights and piston skirt .

The broken piston was cylinder 8 ? the cylinder out of round is number 7 , so 7 and 8 are on the same bank and next to one another ?
Is number 8 bore out of round aswell

Bad news man , can you see why garages don't want this type of work ..... one missed thing and it all has to come back out .

Any ' breaking cars ' with a full engine s for sale ?

Well its Friday and a few bottles of Stells is better than a little cry in a dark corner.
I think a replacement engine is the way forward

I noticed a s8 engine for sale on gumtree the other day

Yes I checked and all pistons have a full clear cycle, all come to the top at the same level.
Number 8 is next to 7 and is perfectly round
Its almost as if the damaged piston in 8 has been swapped from 7 as the damage to cylinder and piston match but this engine has never been out. I will tidy the garage today and have a fresh start