Possible dead engine :( edit: new engine on way :)

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Whoa... Big Mess.

For the con rod to bend that much... It's impressive. Shows how strong they must be.

So we know:
- the piston is siezed (from the mech's original appraisal)
- the con rod has deformed under compression. It certainly looks like the rod was trying to push a stuck cylinder up rather than pull one down.
- the rod has impacted through the side of the piston and the cylinder wall.
- the gudgeon pin sheared off with remainder in the piston.
This follows logically from the rod trying to push the siezed piston up. Something had to give.
I suspect that the piston was stuck, the rod pushed up and deformed under the load and then came into contact with the cylinder sidewall. This effectively braced the rod and then put more pressure on the gudgeon pin which sheared and then the still quite length rod smashed its way through the sump.

That must have made one fecking loud bang when it let go!

- the next con rod has been damaged by the fallout.

Be interesting to see the state of the piston from the top with heads removed.

[PhilT]

Might be time to rename the thread.... "Possible dead engine"

[bam_bam]

image.jpg

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Two more pictures I was sent this morning.
Looks a pretty big mess, any thoughts?

Automotive equivalent of scat porn...

[Rs4mar]

Might be time to rename the thread.... "Possible dead engine"

If only I knew how to? Was thinking the same the other day

[Rs4mar]

Whoa... Big Mess.

For the con rod to bend that much... It's impressive. Shows how strong they must be.

So we know:
- the piston is siezed (from the mech's original appraisal)
- the con rod has deformed under compression. It certainly looks like the rod was trying to push a stuck cylinder up rather than pull one down.
- the rod has impacted through the side of the piston and the cylinder wall.
- the gudgeon pin sheared off with remainder in the piston.
This follows logically from the rod trying to push the siezed piston up. Something had to give.
I suspect that the piston was stuck, the rod pushed up and deformed under the load and then came into contact with the cylinder sidewall. This effectively braced the rod and then put more pressure on the gudgeon pin which sheared and then the still quite length rod smashed its way through the sump.

I will push for some more photos, any ideas with the new photos what might've caused it?
That must have made one fecking loud bang when it let go!

- the next con rod has been damaged by the fallout.

Be interesting to see the state of the piston from the top with heads removed.

[Rs4mar]

Sorry was meant to say ill push for some more photos. Any new ideas as to the cause with the new photos?

[Rs4mar]

Audi have said an assessor is coming down tomorrow so hopefully either way I will have a definate answer

[stu]

Whoa... Big Mess.

For the con rod to bend that much... It's impressive. Shows how strong they must be.

So we know:
- the piston is siezed (from the mech's original appraisal)
- the con rod has deformed under compression. It certainly looks like the rod was trying to push a stuck cylinder up rather than pull one down.
- the rod has impacted through the side of the piston and the cylinder wall.
- the gudgeon pin sheared off with remainder in the piston.
This follows logically from the rod trying to push the siezed piston up. Something had to give.
I suspect that the piston was stuck, the rod pushed up and deformed under the load and then came into contact with the cylinder sidewall. This effectively braced the rod and then put more pressure on the gudgeon pin which sheared and then the still quite length rod smashed its way through the sump.

That must have made one fecking loud bang when it let go!

- the next con rod has been damaged by the fallout.

Be interesting to see the state of the piston from the top with heads removed.

So might bad oil at the service still be the culprit or have we moved on from that? In my (rather limited) mechanic's brain I can't see how the oil's breakdown could cause near instantaneous seizing of a single cylinder head and the bending of a conrod. Surely you'd get engine-wide friction, ramping up over the course of tens of seconds before total seizure?

(apologies if someone's already discussed this - I've been following this post since day one. We're now on page 12!)

Every day's a school day on here

Crossing fingers for a good outcome, Martin!

[ArthurPE]

the bottom pic
is that a broken piston lodged somewhere?
looks like trapped betwen and end plate and crank counter-weight
which cylinder are we looking at?

without knowing which direction the rod was facing it's hard to tell
imo the big end cap bolts broke, the rod went free and was trapped between the block and crank bending it and busting the block and pulling the pin down and snapping it and the piston
it would be nice to see a pic of the crank journel for the damaged rod

to bend it under compression like that would take massive force, bending moment or shear not so much

[ArthurPE]

So might bad oil at the service still be the culprit or have we moved on from that? In my (rather limited) mechanic's brain I can't see how the oil's breakdown could cause near instantaneous seizing of a single cylinder head and the bending of a conrod. Surely you'd get engine-wide friction, ramping up over the course of tens of seconds before total seizure?

(apologies if someone's already discussed this - I've been following this post since day one. We're now on page 12!)

Every day's a school day on here

Crossing fingers for a good outcome, Martin!

I agree, Audi only uses synthetic oil, of 2 grades 5W30 or 5W40(US) and some heavy stuff for the R8 GT, none of which would do this in 3000 miles
even a non-synthetic would only accelerate wear, or the wrong weight might mess with the hydraulic controls (cams, etc.) but not frag the engine
besides, I doubt a piston could sieze so hard that it would do this, it would shear the rings and destroy the walls, but bend the rod? hard to imagine

severe detonation could do something like this but the piston top should tell that tale

we can see what happened, but it may be impossible to determine WHY it happened
the ECU datais critical

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I don't think it was oil itself breaking down but some other issue with the oil system. Perhaps blocked jets in the cylinder?

I think The key thing is the bent rod. As Arthur says that's a phenomenal amount of force to bend that and if the cap bust it wouldn't be connected to the crank. As such I cant see any way that it would be able to exert enough force to bend the rod and shear the gudgeon pin.
my view is still the piston got stuck/siezed somehow.

Detonation is an interesting option- certainly enough power but I wouldn't expect that kind of damage under light cruising loads.

[murph7355]

The second picture does look like the piston, but it looks way too low and there look to be gaps around it. Can you read the text in the captions you have Martin?

If it had seized, wouldn't it have done so in its bore somewhere and hence not be visible where that is? And to bend the rod like that, wouldn't it practically have had to become part of the block?!

If the rod's connection with the crank had been compromised, might that have allowed the piston to travel further down the bore? Perhaps then with the rod coming away from the crank and getting stuck then bent, smashing the gudgeon pin in the process?

Have they given you the ECU results?

[Rs4mar]

''Still very difficult to know the actual cause as there is a lot of damage to the engine. Something has gone wrong in cylinder number 8 but as you can see from the pictures it could be con rod, piston, piston rings or the pin. Audi now are looking at the photos and will get back to me today. I will let you know''.
That's the email I got today with the photos.
I did hear from the warranty company that the ecu had no codes present etc, but as for data they haven't said?

[G.Mac]

Fingers crossed here for you, hope it all goes well. I wouldn't be bothered about the issue of having a new engine in the car as far as re sale goes, keep all the pictures and document the history of the fault for the new owner. Ensure the new unit is run in properly and in my opinion the new engine could be a positive selling point!!! it would be for me if I were on the lookout for one.

[murph7355]

''Still very difficult to know the actual cause as there is a lot of damage to the engine. Something has gone wrong in cylinder number 8 but as you can see from the pictures it could be con rod, piston, piston rings or the pin. Audi now are looking at the photos and will get back to me today. I will let you know''.
That's the email I got today with the photos.
I did hear from the warranty company that the ecu had no codes present etc, but as for data they haven't said?

Getting to the point where I'd be saying to them that the precise detail is academic. Doesn't look like something you've unwittingly caused, so get a new engine in the car, get it back to you and Audi and the warranty provider can marvel at the cause at their leisure.

You've been without the car for nigh on 3wks now and I would bet you have another 2-3 even if they started replacing it now.