Ahh, sludge... How I loathe thee...
Your pictures bring back many memories, of just about every valve cover I have pulled on Extended-OCI vehicles... Some were better, some about the same, many far worse.
A friend's '00 A4 1.8T Quattro 5MT with 73k miles at the time was so bad that it was almost impossible to distinguish one part from another. We took the Valve Covers off in order to install new cams, valves/retainers/springs, and to replace the VCG with one matching the HG and rated for 800hp... Needless to say, plans were put on hold. The guy is a car nut too, and has been modifying that car nonstop since he got it in 2004 (with custom twin-turbo conversion using hybrid Garrett/K04 turbos, APR FMIC, Methanol Injection, Samco Sport intercooler tubing, big injectors (i think 40#? idk exactly), monstrous 4" inner diameter carbon fiber intake, Aluminum Flow-Matched Intake Manifold, 3.5-4" Downpipes, Cat-Delete, and 2.5" full-dual-pipe exhaust with Corsa pass-thru mufflers... Monstrous power, has the suspension to handle it and more incl KW Clubsport Coils/3way adj 26mm frknt and 32mm rear sways/Stg4 Camber Plates/Chromoly Fr+Rr 4-point strut tie bars/etc, a pair of 2009 Cayenne Turbo Calipers + 2pc slotted/drilled rotors up front and 2008 RS4 front calipers+2pc rotors in rear, diffs from S4 w Quaife insides and some kind of center diff-AWD-thing upgraded to change power transfer to 20/80 front/rear normal with up to 100% rear or 60/40 f/r, ridiculously awesome Kinesis 19x9.5f 19x10r wheels in Gunmetal typically wrapped in PS2's size 255fr and 275r, RS4 fenders and quarter panels with an extra inch of pull to fit 10" front and 11" rear wheels at the track, and a mix of S4 and RS4 body parts w some aftermarket carbon bits... Only close friend whose car keeps up with me on a straight line and the twisties). He is one of the people who kickstarted my "too much is not enough" modding disease when on my birthday years back he gave me a "starter package" consisting of an AFE intake, Conforti Shark Injector software, UUC Underdrive Pulleys, and an O2 Simulator (which he said I would be needing soon enough... He was right). So ever since, we always try and buy the other something unique that they don't have, as we figure we will be spending it anyway and since we have each spent hundreds of hours wrenching on the other's car, this way is way more fun and keeps us thinking outside the box.
Sorry for that, I guess my ADD is getting the better of me...
Point being, he is as fanatical about maintenance as I am, perhaps moreso considering the insane boost those turbos push (regardless of ridiculously beefed up internals)... Up to that point he had been running whatever synthetic oil it is Audi dealers sell, with Mann filters, at 5-7k OCI's. Everything was replaced at 75% of the recommended interval, and nothing was overlooked... He had replaced the entire PCV system 3x at that point, and the EGR/etc at 30k and 60k. Cabin filter every 10k and fuel filter every 2-3 OCI's, trans fluid was fully drained and refilled with RL every 30k or 24mo, diffs all with RL every 20k or 18mo, brake fluid every 16mo/15k, and PS fluid was done with turkey baster every 30k (although he would pull out as much as possible, fill, and 200mi later do it again, until 1k miles had passed, and he always removes 1/2-1qt and refills at every OCI)... Coolant fully flushed every year (always in May), used Audi coolant in a 25:75 coolant-water ratio with exactly 1.2 bottles of RL Water-Wetter, and every third year he pulls rad and flushes it with something I have never heard of, as well as straightening out every single fin (Fluidyne rad..).
So you can see why I was amazed when his valvetrain looked like it got hit by a road tar sprayer. I know he was, because I thought he was going to cry. I persuaded him not to buy any kind of flush, having gotten my cars completely decrapified without anything so harsh, and we did the following...
- Drained oil, pulled filter, dropped pan
- I drove us to PepBoys where we got: 4x bottles regular Seafoam and 4x bottles Deep Creep, 1gal MMO, 6x Redline SI-1, bottle of LiquiMoly MoS2, 10qts Generic Syn 5w30, 10qts Pennzoil Ultra 5w30, 20qts Royal Purple 5w40 (SM, "Euro Blend"), as well as 10 K&N oil filters (his money... I know he was saying that if the top was that bad, the unseen stuff must be terrifying)
- Went to Audi Dealer and got 2x PCV valves and hoses, 4x VCG's, 4x Oil Pan Gaskets, 4x Fuel Filters, and two sets of NGK plugs
- Stopped at store to get 5 6packs of Flying Dog beer
- Poured regular Seafoam into.spray bottle (Windex bottle) and coated the oil pan, and put a lighter coating on top end; did this about four times, as it soaked in (sludge actually "swelled" and there was now small amounts of dark black liquid)
- manually scraped oil pan and very carefully removed top end gunk by hand; oil pan was then washed down with a 3800psi pressure washer; oil pickup screen removed and gently cleaned by hand
- put oil pan back on temporarily, removed plugs (only 10k old), and did a 18hr Seafoam Piston Soak, and took oil pan off to see results (solid black liquid)... Did this 2 more times, and the 3rd time we noticed that after 24hrs there was only about 25% of the liquid in the pan so we got the rest out with rags, manually cranked the engine, and did it one more time (50% more Seafoam, too)...after 36hrs, only about 5-10% made it out, so things looked good, or at least better, in that regard
- put plugs back after cleaning them, used shop vac to ensure no sludge was loose and missed, sprayed 6oz of MMO onto the top end (didnt know what it was at the time), put VC on, oil filter in, and filled 90:10 generic syn oil to MMO; drove for 200mi keeping eyes glued to oil press/temp gauges, and then immediately dumped the oil and pulled filter. Oil came out pitch black and filter was as well, with little sand-sized black specks on it
- poured in an 80:20 Generic Syn/MMO mix and drove for 1k miles w new filter, dumping it when hot again...
Followed with gradually increasing intervals of PU and MMO (1k, 1.5k, 2k), with 200-500mi at the end having 0.75oz/qt, 1.25oz/qt, and 2oz/qt of Seafoam. Any longer and there was so much solids in suspension it seemed unwise...
Pulled VC and dropped pan, with a significant improvement... Still visible sludge, but a lot less. Varnish was only about 1/2 as thick, also.
We had been running 93oct Shell E0 pure gas, and used a full bottle of SI-1 every third tank. TB was cleaned with SF, and we did the Brake Booster seafoam treatment (thru PCV and SAP lines too, all at same time).
Switched to RP 5w40 and did 3k OCIs w KN Oil Filters (changed every 1.5k), and after 3 OCIs the sludge was 90-95% gone, and about 1/3 of the varnish remained.
Ordered and ran Redline 0w30 for 3x 4-5k OCI's w frequent filter changes, and it was unbelievable...
Not even the varnish was left!
Removing the entire valvetrain and the old looked immaculate, pistons were spotless, no gunk.anywhere.
When he had his engine built (same idea as mine, except he got an all new forged crank, I reused mine), it was spotless. This was at 120k miles or so, and he had been running nothing but RL 0w30 and occasionally RP 5w40 since we cleaned it out.
Of note, the guy who did his engine, a VW/Audi/Porsche specialist, said he had never seen a 1.8T with that kind of mileage be not only so clean, but show such relatively little wear.
Now, it is a bored and stroked 2.2TT technically, and it is wicked... However, he has been talking about selling the engine and buying a motor from a wrecked RS4 and swapping the Twin Turbo kit to it...
It is a sickness.
Hope that gives you an idea of how hard it CAN BE to get to 100% clean. Granted his is a needlessly complex FI engine, but same principle applies... Start slow and use quality products, and pay very close attention.
Doing my cars, especially the Bimmers, was relatively easy compared to his... Just RL+RP (and a hint of Seafoam), two dozen KN oil filters, and shiny-clean.
Good luck, sorry for the length!