Continuing the saga of my broken 3.6. I guess it wasn't as healthy as i thought.
There is definitely a failure of some sort, as there is now water in the oil. Also, the right hand bank has a lot of water moisture in all 4 cylinders, as seen on the spark plugs. But especially #1 cylinder.
Left hand bank, there are 2 plugs with a little bit of moisture on #5 and #6, and oil on #7 and #8.
So, I am now in the process of stripping the top end down for a closer look. Presumably, I should be able to get the entire induction section and fuel rail assembly off in one unit. I will try anyway. I want to do as little dismantling as possible, as the car may remain in a part stripped state for some time. And I can't justify the expense of someone else tackling the job.
And there was me hoping the biggest job to was getting the timing belt covers off, which was a tale in itself.
If there is something more serious going on, like cracked heads or block, then a replacement engine might be in order. Is the 4.2 a fairly straight forward transplant? Ie. buy a ABH, and bolt it in. Or will there be transmission issues, etc?
the 3,6 automatic transmission will probably not last for too long when you add another 60Nm as produced by the ABH to its load. So it would be a good moment to switch to a manual gearbox, as you've planned it anyway, as far as I understood you in the first postings. It would also help on avoiding problems with the wiring harness, as the PT and the ABH (or better said: Pre-Facelift and Post-Facelift, but each ABH ist Post-Facelift) have different wirings (at least at some points).
In general, I haven't _read_ about any cracks in a V8 head the last 8 years, but that doesn't mean it couldn't happen. Regarding the instructions on how to remove everything, I've sent you an email a couple of days ago. I'll PM you again.
After much blood letting, skinned knuckles and an aching back, the 2 heads are off, and the headgaskets and mating faces look fine. There's signs of porosity on the right hand head, in the exhaust ports, but not to a massive level.
So, I'm pondering my next move, while getting prepared for what it is.
In the meantime, having cleaned everything up I have found-
Crack in the block. Between the centre inboard middle head bolt (if that makes sense) and the water jacket, right bank. Damage on the sealing area of the block for #3 cylinder. Meaning that for a section the 'fire' ring, the actual seal is performed by a area only 2mm wide, and 20mm long, with the damage going straight into the water jacket. 2 other cylinders have a small amount of damage similar, but not as extensive. In the right hand head, #2 exhaust port, signs of porosity.
And a few clues that this has all been apart before, and hastily put back together.
It's not good news. I presume the bores are Nikasil? Does this preclude any machining work on the block? I would be tempted to have the block face machined, if possible.
Alternatively, the hunt is on for a 4.2 litre ABH engine.
I don't know, whether the block is Nikasil coated. But I guess the head bolt bores aren't. Why do you want to machine the block faces? What about the crack at the bolt bore? The blown gasket is the smallest problem. Shoot some pics and send them as email attachment, as you want to.
the cylinder's aren't coated at all, the alloy is called "AluSil".The Nikasil thingy is an urban legend and has been disproved some time ago by a chemical analysis of both ABH and PT blocks.
Sorry to hear that you have that big problems. Keep your eyes open, there have been several Audi V8 sold lately on ebay.co.uk. One was sold for below 300 pounds I think and had little miles on it. Several defects, but the engine was fine (at least it was stated so). Easier than overhauling the engine!
first photo, the darkened area close to the cylinder, and going over to the water jacket is a depression in the aluminium, which is possibly where the combustion gas was leaking into coolant
second photo A crack between the water jacket on the right towards the head bolt hole in the middle.
Well, the stripdown of the engine bay is in full swing. Certainly not what I expected to be doing.
As it all comes apart, the bits are being cleaned and checked to make sure there's no nasties. The intention is to have the block welded, then skimmed, and the heads skimmed.
Major task at this moment is manoeuvring the block out. The service manual only makes reference to the 4 bolts across the top holding the block to the transmission. I guess the starter motor is part of the securing too.
I've not found the ECU and TCU. Is there much to dismantle to get to them? It's a right hand drive car.
I've aslo dropped the Gearbox oil- just a little over 4qt.
In general, it is all coming apart relatively easily. I should do some pics of the head faces, for before and after!
