UrS4 2.2T Avant project

[Acki]

It's a JE piston? They have often trouble when you are not using the HD pins.

Pre ignition (SPI) you can have with and without knock event.
This event can cause a very high pressure which can destroy nearly everything.
You have different types.

Glow ignition is another unconventional combustion mode.
Too advanced ignition angle with high octane fuel can cause this. ;-)

[Thuppu]

What ever the case was, the block is fubar(can be bored to 83mm) and one piston. Propably can save the rod by changing the bushing, and one piston should be possible to order. Luckily the balanced crank is fine. But these parts arn't first priority atm. Have a 7A block waiting for these parts though.

[prj]

Preignition usually just silently melts the piston, rather than lift head, destroy pin etc.
Also, in that case it would be cyl 3 or cyl 4, they are much hotter than cyl 2.

Something else is amiss.

[Thuppu]

The main issue was that the engine burned oil... really much oil... I mean a ton of it... I mean worse than a TFSI. I think that lead to e85 pre-ignition and high cylinder pessure, caused burnt spark plug electrodes, burnt valves, propably lifted head becase of this and in the end hammered the piston pin. This is just my theory.

[igor136]

Did you have measure clearance between the pin and the rod bearing before?

[prj]

I wonder WTF happened.

Regarding hot running on AAN it is always Cyl 3 that is the hottest, followed by Cyl 4 and only then comes Cyl 2.

[AndyP]

Dam, that sure took a pounding!!

[Dima ABY]

Wow!!!
Looks like this engine has not worked a lot.Pistons are shining.
Sorry for that.

[K Simmonds]

Wow, that came from an engine that was still running!??! It would certainly explain the noise.

[V6quattro]

[Thuppu]

Back to old good times... or not. I did take apart the old block with forged internals that have been lying in the garage for a couple of years. This engine had the big oil burning issue, and in the end it started to keep some noise. This was found in cyl no 2.

[quattro-nick]

Where'd you get that banjo bolt?



I had to make my own bolt with 1/8 NPT thread...

my father had a some used banjo bolts so therefore i do not know exactly where it comes from

[mushasho!]

I also had this problem in the past so I have set my fuel pressure higher and problem was solved (i'm using a adjustable fuel pressure regulator)
here is a picture where i measure the fuel pressure on AAN fuel rail

Where'd you get that banjo bolt?



I had to make my own bolt with 1/8 NPT thread...

[Thuppu]

Ok, thanks!

[Tille]

From my experience:
S2 2.5l 908PS E85 1980ccm Injectors 100% DC
S2 2.2l 780ps E85 1980ccm Injektors 90% DC

So its ok i think