munched engine...ouch! not for the faint of heart

[ArthurPE]

a members engine is destroyed by cylinder scoring...
http://www.audizine.com/forum/showthrea ... ost5511801

chicken or egg?
scoring caused possibly increased deposits and coking?
or the deposits caused scoring?
Audi says it was improper (or contaminated) oil...
please discuss...

this engine's valves were cleaned
and as some may recall I (amongst others) warned this may cause as many (or more) issues than it solves...

let's keep it technical

[Sims]

Where is Audi's report?

[stoddie]

i'll throw in my opinion.

ive read many threads on here regarding carbon build up.

Im a marine engineer offshore so i kind of know what im on about when it comes to engines.

This is all in my view of course!

I dont think cleaning valves in place is ideal, and i suspect the cause of this scoring is due to the residue from the cleaning.

I read he used 4 cans of carbon remover, if the valves are restricted from closing fully by the carbon, this cleaner will run down the bores along with the carbon which has been removed. and will settle in the ring grooves. this could cause sticking rings, the chemical will cause bore wash and on the initial start up of the engine the cylinder will have no lubrication film on it until splash lubrication has covered the lower bores.

I dont know if the poster changed his oil after the cleaning had taken place. Again if any cleaner/carbon was to pass through the valves, down the cylinder, through the rings it would be dripping into the sump, not ideal! this could lower the viscosity of the oil. The hard carbon particles floating in the oil would also be splashed around the engine leading to further wear.

[scaghead]

a members engine is destroyed by cylinder scoring...
http://www.audizine.com/forum/showthrea ... ost5511801

chicken or egg?
scoring caused possibly increased deposits and coking?
or the deposits caused scoring?
Audi says it was improper (or contaminated) oil...
please discuss...

this engine's valves were cleaned
and as some may recall I (amongst others) warned this may cause as many (or more) issues than it solves...

let's keep it technical

looks like you were right all along arthur

[scaghead]

i'll throw in my opinion.

ive read many threads on here regarding carbon build up.

Im a marine engineer offshore so i kind of know what im on about when it comes to engines.

This is all in my view of course!

I dont think cleaning valves in place is ideal, and i suspect the cause of this scoring is due to the residue from the cleaning.

I read he used 4 cans of carbon remover, if the valves are restricted from closing fully by the carbon, this cleaner will run down the bores along with the carbon which has been removed. and will settle in the ring grooves. this could cause sticking rings, the chemical will cause bore wash and on the initial start up of the engine the cylinder will have no lubrication film on it until splash lubrication has covered the lower bores.

I dont know if the poster changed his oil after the cleaning had taken place. Again if any cleaner/carbon was to pass through the valves, down the cylinder, through the rings it would be dripping into the sump, not ideal! this could lower the viscosity of the oil. The hard carbon particles floating in the oil would also be splashed around the engine leading to further wear.

you have hit the nail right on the head fella. well said

[ArthurPE]

I warned him of exactly the same things
more damage than fix...imho, deposits are not an issue...
it appears cleaning them may be...

in fact, he showed some borescopes a while ago and at that time I told him he most likely destroyed the engine...

if you are compelled:
roll the car to make sure the valve being cleaned is closed
vacuum tubes in the valve and in the (removed) sparkplug hole
roll the car to open the valve, compressed air into the plug hole, debris out the valve when finished
change the oil before running the car...

but I still ask why?

i'll throw in my opinion.

ive read many threads on here regarding carbon build up.

Im a marine engineer offshore so i kind of know what im on about when it comes to engines.

This is all in my view of course!

I dont think cleaning valves in place is ideal, and i suspect the cause of this scoring is due to the residue from the cleaning.

I read he used 4 cans of carbon remover, if the valves are restricted from closing fully by the carbon, this cleaner will run down the bores along with the carbon which has been removed. and will settle in the ring grooves. this could cause sticking rings, the chemical will cause bore wash and on the initial start up of the engine the cylinder will have no lubrication film on it until splash lubrication has covered the lower bores.

I dont know if the poster changed his oil after the cleaning had taken place. Again if any cleaner/carbon was to pass through the valves, down the cylinder, through the rings it would be dripping into the sump, not ideal! this could lower the viscosity of the oil. The hard carbon particles floating in the oil would also be splashed around the engine leading to further wear.

[P_G]

Rather then clean the valves until you can eat your dinner off them is there merit in take the top crust off. Having not opened my engine up how much space is there between the valves and intake manifild flaps for example?

I only ask because last week a work colleague with a DI 3.0TDi C6 A6 Allroad had his intake manifold replaced under warranty on the back of a P2010 code. And it is a common problem in 3.0TDi units accordng to Audi although the symptoms are obvious too, high fuel consumption, hesitation at low revs occasional kangarooing.

BTW my EPC light came on again tonight 8 week since the last time so I may yet open up my engine in September to inspect / replace the potentiometer and assess whether to do a light clean then. I have noticed that in the last couple of weeks first thing in the morning it does run rough and the exhaust flaps rattle for 5 or so seconds as if lack of vacuum until I blip the engine and then all is fine.

[ArthurPE]

I would be very cautious....

perhaps a wire/nylon brushing and a vacuum, leaving the encrusted stuff in place...

valves to flaps, guessing ~4 inches...
you can see the flap axles by inspection, and the valves are a few inches beyong the manifold/head mating surface

Rather then clean the valves until you can eat your dinner off them is there merit in take the top crust off. Having not opened my engine up how much space is there between the valves and intake manifild flaps for example?

I only ask because last week a work colleague with a DI 3.0TDi C6 A6 Allroad had his intake manifold replaced under warranty on the back of a P2010 code. And it is a common problem in 3.0TDi units accordng to Audi although the symptoms are obvious too, high fuel consumption, hesitation at low revs occasional kangarooing.

BTW my EPC light came on again tonight 8 week since the last time so I may yet open up my engine in September to inspect / replace the potentiometer and assess whether to do a light clean then. I have noticed that in the last couple of weeks first thing in the morning it does run rough and the exhaust flaps rattle for 5 or so seconds as if lack of vacuum until I blip the engine and then all is fine.

[ArthurPE]

Where is Audi's report?

it's not completed yet:
need to open the oil filter and inspect for trapped material
analyze the oil
inspect the sump and main bearings

they have verbally told mal that it was oil related...

it's obvious

the scoring runs top to bottom indicating the oil scraper ring did the damage as it cleared oil off the cylinder wall...carbon deposits would not cut that deep...it would have to be hard...like bearings or oil pump impeller steel...

[Sims]

they have verbally told mal that it was oil related...

...

I must have missed that on the Audizine thread, does he mention it on there?

[ArthurPE]

they have verbally told mal that it was oil related...

...

I must have missed that on the Audizine thread, does he mention it on there?

yes...unless he edited it...

[rsierra]

IMO the damage would have happened on initial start up after a carbon clean. I believe his valves were cleaned months ago. He also posted data logs showing good timing advance and airflow numbers post cleaning.

IMO, it's something other than a shoddy carbon clean.

[silverRS4]

The competence of the private shop mechanic (or Audi tech) would only have to be slightly above dim to avoid any problems at all with the valve clean procedure. Not to mention, the standard procedure (soaking and scrubbing the valves) is what is typically used by Audi. The walnut shell blasting method requires more hardware and slightly more competence. At any point in engine rotation 5 or 6 of the cylinders have their intake valves completely closed. With knowledge of the firing order and a quick glance at the valves relative to the valve guides, it's pretty easy to see what valves to work on first. If one is questionable (valve not closed or not seated fully), that port certainly won't contain the cleaning solvent for very long; and if that port does leak down even a CC of solvent, you simply remove remainder of the solvent, remove the spark plug and let the cylinder vent. Only a complete idiot would goof up enough to actually allow a large volume of solvent in a cylinder. Likewise, using this same procedure, and a vacuum to suck out carbon-based remnants from the valve seat area when you are done cleaning, it is very unlikely that carbon-based material would enter the cylinder as a result of cleaning. Per chance a particle does enter the cylinder (which is normal occurrence anyway with carbon buildup in the inlet area of FSI engines), it may bounce around in the cylinder a few times before getting pushed out on an exhaust stroke or it may impact an injector or spark plug. It will not score a cylinder. It looks to me like there is only one pic in the mentioned thread showing fairly deep lines, but they are below the highest point the rings reach. That would tell me that particular gouge was from a metallic particle introduced from the oil ring or from oil spray from below. Oil contamination? I vote yes. Scoring from carbon? I don't think so.

[stoddie]

compression was down - which either means blow by on the piston rings, which would basically blow the contents of the sump back through the breather pipe and back into the head - as far as i can tell from what ive read on the post this wasnt happening.

or

the valves were so badly fouled that they could not close properly.

i also read on here - not sure if the thread was related or not - that a lot of people were filling the ports with rags etc, soaking them and leaving them over night to soften the carbon. 4 cans of solvent = approx 2 litres (almost half a gallon to you american guys) thats one hell of a lot of solvent. who knows if it runs down the cylinder? and leaving the spark plug out aint gonna stop it running down either.

what do you reckon caused the contamination of the oil silverRS4?

too much of a coincidence in my opinion that so soon after cleaning the bores are marked. Carbon will destroy any hydrodynamic oil film on a cylinder wall and cause microsiezure of the piston ring. As soon as this ring and the cylinder wall start to break up it keeps snowballing until the ring no longer makes contact with the cylinder.

[2manytoys]

Guys, it's my engine. If you read the thread on AZ I had major carbon problems and pinging before anything was done.

Audi first "cleaned" the valves, but didn't do a good job. My independant then did it properly. Please note, it took two days, and yes, he was making sure the valves were shut and cleaned everything out (this guy builds race engines, and knows the Audi's very well).

Again, I had big problems with timing (9-13 degrees advance max) and pinging before the manifold come off for the very first time.

I'm not sure what actually caused it either. Was it excess carbon (the first problem) that caused scoring, then more blowby, more carbon, more scoring, or was it another issue (the bottom end hasn't been opened yet, so maybe there is more happening there).

Yes, Audi said oil, but I change my oil every 7000km. I do this because I notice the oil temp (average) goes up only after 3-4000km. As on AZ, I use Castrol SLX iii (the approved oil in Australia for RS4's). In Australia even Castrol Edge is not recommnded for the RS4 (maybe because of our hot temps??)