Re: Oil by throttle body etc!

[Colorado-SHOBro]

Got your email...Piston 5 looks worse but even though the vid is pretty clear I can't tell if my eyes are playing tricks on me and the way the carbon build up looks funny or if there are chunks out of the perimeter of those pistons...I'm thinking chunks are gone but you'd think it would not run as well as it is.

I'd be curious how the compression test turns out.

Don't you have over 100k on it? You'd also think if chunks were gone from the pistons that the valves would be bent or damaged and the turbos would be destroyed

It certainly looks like the edge of the pistons are chipped to me. Car just hit 50k yesterday. Whatever damage is done it certainly isn't affecting the drivability of the car. Car idles smooth, never ever any misfires, and no loss in economy. A couple weeks ago when i discovered the oil ingestion issue at the track it even turned an excellent ET comparable to what it ran last year.
I'm still getting oil in the TB and intake after WOT pulls but not sure if the pistons are the culprit there. Could be that or the turbos are still in question as well.
I will try to do a compression check later this week. In the meantime i'm eyeballing used SHO's on the market after seeing the state of the pistons.
I've still got 30k miles left on my warranty but i really don't want to hassle with getting the dealer to diagnose the issue, probably just blaming and replacing a turbo or both if i'm lucky and then i'm still stuck with the damaged internals.
If i could find and fix the oil ingestion issue i might consider keeping it.

If i had to guess what caused the damage i think it goes back to when my oil separator failed and the car ingested a ton of oil. I fixed the separator and installed the downpipes a day or so after that.
I did some WOT pulls after the DP install and got a max of 6* kr which is abnormally high(usually 2* max). After these pulls i realized the motor was sucking up oil that had built up in the intercooler during the oil separator failure. I pulled almost a quart of oil out of the intercooler. I'm thinking all that oil in the cylinders caused a low octane condition, and the detonation occurred causing the damage.

Any thoughts are welcome guys

[SHOdded]

Not even sure there IS any damage, unless you experienced severe knock/detonation events that you can recall.  Shapes and shadows of carbon deposits can be a misleading diagnostic.  There was no visible wall scuffing, so rings look good.  A compression test at this point may not yield anything since no noticeable performance deficit has occurred.

At this point, try the standby tests:  revert to a stock tune and compare results.  Or take off the wastegate mod and compare results.  Make one change at a time so you can pinpoint the most likely culprit.  If you are VTA, check the diaphragm seal(s), revert to stock.

[Izzybird]

I'm going to have to agree with shodded, pistons look fine. It's a little ugly around the edges, but if there were chunks missing it would be entirely different in appearance. Not to mention wall scoring at the very least. As for the oil, my stab in the dark is your rear turbo. They seem to be dropping like flies, just replaced mine at 50k. Here's a snap of detonation failure, even with the carbon ring around your edges you would be able to tell the depth differences.

[Izzybird]

Also, I know you said you haven't seen any excessive smoke. When my rear turbo started pushing oil I noticed a pretty good haze out the exhaust when laying in to it, kinda like a good running performance diesel would. It was really hard to see from the drivers seat, but very noticeable at night with headlights behind. There was also a fine layer of soot on the back of the car that I had to clay off, you may not notice that from the color of your car. The intake hose blew off at the throttle body one day, scared the bejeezus out of the wife, and shot oil all over the beauty cover and such. Never noticed any difference in performance, was just cleaning the MAP every dang week.

[Colorado-SHOBro]

Thanks for the replies guys. Glad to hear you don't see anything too alarming. Perhaps i could be overreacting. The part that stand out to me as far as looking damaged occurs by the dimples in the piston. Compare the 2 following pics:
This one you can see the creased edge on the dimple of the piston. The cast looks complete


On this one that crease or edge of the dimple looks like it's missing

That to me looks like "damage" but i could very well be wrong. And in fact i really HOPE that i'm wrong. I know it is tough to get an accurate depiction with camera angles,shadows etc.
However, these videos did turn out pretty clear.

At this point i'm pretty much doing as SHOdded said and changing one thing at a time to isolate the issue. Catch can has been removed, I returned the one VTA BOV back to stock yesterday and will probably load the stock tune sometime soon. However, i don't see that having much of an effect other than lower boost pressures so maybe i'll get less oil ingestion.

Once i return to stock i'll be taking it to the dealer to have them assess the issue. I just have to decide if i'm going to go through the hassle of switching out my downpipes before i do that.

[SHOdded]

It is perplexing indeed, hope it is not an internal engine issue!