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#21
8th May 2021, 07:44 PM
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A slightly delayed update from Monday as I needed to talk to Mark about what I found before posting it, and then I was ill for the rest of the week
 The engine has been steam cleaned on the inside! It turns out this mayonnaise is quite a good detergent. The cam bearing journals are still perfect so no bearing damage  At this point I built a pressure testing rig which was derived from my radiator pressure tester. I hooked up a header tank and either looped or blocked off the various water pipes, vacuum filled it, and then pressurised it to 1 bar. This was the result  There is a crack in #7 exhaust port.The water pools up in the port when the valves are shut, and drips out of the inlet manifold When the valves open it pours in to the cylinder and sits on top of the piston The water in the sump is from the water seeping past the piston rings So, the left (bank 2) cylinder head is toast, and used heads are pretty much unobtanium. It might be possible to find the crack and weld it, but it would be contaminated with water and soot so welding would be extremely difficult, and not economically viable. Having discussed with Mark we decided the best way ahead is a replacement engine. 
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#22
8th May 2021, 08:16 PM
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Having made a shopping list and ordered a bunch of parts, I wanted a better look at the broken engine to see if it is saveable, should a head turn up in the future. Also, we wanted to see if the cam chain tensioners were still good, as I know the ones on the replacement engine are not.
Bank 2 tensioner removed - this crud in the oilway is what destroys the filter gauze which then kills the tensioner. I've never seen this much before though. I think this is gunge from the mayonnaise detergent effect cleaning everything out Amazingly the gauze has survived! Alas the bank 1 gauze and consequently tensioner has not survived. No idea why its always bank 1 that goes first. The start pin still locks, but the non-return valve doesn't close fully so this will make a very brief rattle on startup, but not frightening clatter that the start pin causes. The creamy slime drips out of every oil way Well, you can tell which cylinder was ingesting water  Its spotless!The head has been cleaned too The cylinder wall is perfect though - I feared the water may have washed any lubrication off the bore and caused it to be scored by the rings but it has survived, meaning the engine is definitely saveable in the future A slight stain on the cylinder wall from where the water has been dripping in, but there's no damage to the surface. Its just discolouration. #8 #6 I started stripping the engine to clean it up. I want to get as much of the emulsion out as possible before storing it so it doesn't end up separating and leaving the engine full of moisture. Not too bad under the valley cover The oil retention valves are pretty nasty though. I don't want to retain any of this! The upper sump is pretty dirty too - all the usual carbon deposits have been loosened up Very clean in the block though - all the carbon deposits have been washed off in to the sump. Just lots of the emulsion hanging about. Cleaned with carb cleaner. Once I've got as much slime out as I can I will spray the inside with oil to keep it clean until I find a head for it. I tipped the engine on its side with the remaining head down, with the cams removed, so the gunge can drip out under gravity overnight.
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#24
8th May 2021, 09:51 PM
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__________________
Audi S8 D2 2002 88k mls Ebony pearl effect black. Grey interior.
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#25
8th May 2021, 10:08 PM
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They might work, but I'm suspicious why there are no cam chains on them and why the tensioners appear to have been removed. They may well be an equal can of worms, and tbh after shipping and gaskets etc its about even to just get a known-good replacement engine.
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#28
9th May 2021, 09:39 AM
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Yes, I take them out now, on the basis that its less bad to have that gunge go through the tensioner than stainless steel mesh.
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#29
19th May 2021, 08:11 PM
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A tad behind with updates on this sorry. Its taken a little while to work out what to do engine-wise. In the meantime, I tidied up the broken one, since it would go back together when a head turned up.
I cleaned up the block ready to put the lower sump back on For those who may be curious, this is where the crank locking pin goes. Lower sump back on Metal oil cooler pipe I flushed the oil cooler with brake cleaner until no more slime came out, then put it back on Cleaned up the mounting face on the block ready for when a head turns up I'd removed the oil retention valves while the engine was upside down to let the slime drain out. Cleaned them up and put them back in. The breather plate is a; really expensive and b; back-ordered so I cleaned it and re-sealed it using the same silicone as used on the sump. Ready for a replacement head.
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#30
19th May 2021, 08:27 PM
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Having failed to find a head, I acquired a replacement engine. Of course, as soon as the engine was on a pallet heading Southwest, I also found a head
So now I have a spare engine (yay) and Mark's engine is going back together and back in the car I put the cams and tensioner back in the good head New oil seals This head all done This is the replacement head. The inlet valves are fine, but the exhaust valves are leaking slightly so they'll need to be lapped in. This bar is the roller which the rocker arms sit on. The rockers need to come out to get easy access to the valves The exhaust valve seats are a little crusty This is why the head was taken off - the other side suffered a timing incident and exploded. This side ate a small bit of debris and just dinged the head slightly but its still perfectly usable. Crusty valves too Much better 2 done, 6 to go
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