S8 d3 v10 2007 engine torque settings

[audis8tui]

Originally Posted by Delboy

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?

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.

[Delboy]

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.

[audis8tui]

Originally Posted by Mechcanico Lee

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

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.

[Mechcanico Lee]

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






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 ...

[Delboy]

Originally Posted by Mechcanico Lee

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






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?

[audis8tui]

Originally Posted by Delboy

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

[audis8tui]

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.

[Mechcanico Lee]

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 .

[Delboy]

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?

[Mechcanico Lee]

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