More...

 

...And more...





The outgoing 01A 5-speed manual...





The outgoing 2.6 V6 12V...



And the incoming 4,2 V8 32V, mated to an 01E 6-speed manual...

 

The next step is to remove the secondary firewall, then prep the engine bay for paint. I also need to run the new battery cable to the rear, as the battery will reside in the trunk.

 

Update 17th November 2012:

I received new OEM Audi S8 exhaust manifolds-to-downpipes retainers, bolts and nuts. I wasn't happy with the old ones. They looked okay, but they are much easier to replace, when the engine's on the bench.

Also, some may recall I decided to junk the stock Audi S8 combined oil cooler and filter, in favour of a remote set-up. This meant having a custom flange machined out of solid aluminium billet. Now the mounting faces were designed to mate to the aluminium V8 engine block with a gasket as the seal. I've thought long and hard about that, and was a bit worried about the integrity. The Audi S8 oil pressure is in excess of 6 bar (87 PSI) at idle when cold. With a healthy engine, that figure will still apply when hot at 2,000 rpm and beyond.

I wasn't keen on seeing how well a thin card gasket would hold up to oil at 90-odd degrees with 6 bar of pressure. The obvious thing to do was use O-rings as the seal. Unfortunately, O-rings can't just be slapped in. Both mating surfaces are flat, so I had grooves machined into the mating face of the aluminium flange, so the O-rings have nice channels to sit in. Perfecto!

 

Here's the custom-machined flange, as I had it made originally. Note the lack of O-ring grooves:



And machined, to accept two large O-rings:



With O-rings fitted:

 

New OEM Audi S8 exhaust manifold-to-downpipe retaining nuts, bolts and retainers:



Audi S8 exhaust manifolds, with the old rusty bolts and retainers:





Now fitted with new bolts, nuts and retainers:

 

Update 06th December 2012:

I received my spot-weld drill bits in the post today, so the secondary firewall has been removed. I ordered 6 and 8mm bits, as I wasn't 100% sure what size the Audi secondary firewall spot-welds were. I planned to go with 6, then move up to 8mm, but in the end, the 6mm bits did the job perfect.

I'm now left with a hollow box section, which I'm going to plate over with aluminium. I've made a cardboard template. Once she recess is covered, I'm going to steam clean the entire engine bay, degrease it thoroughly, then prep it for paint. Just rub down, primer then 2 final coats of satin or gloss black. Then the 4,2 V8 engine and 01E 6-speed manual tranny can be installed. With the secondary firewall removed, there's loads of room for a big snail to fit at the rear of the engine.

I removed the original heat shielding, which will be replaced once the bay is painted. Some pictures:

Spot welds drilled through in secondary firewall:



Secondary firewall being pulled off:



Secondary firewall removed:





Secondary firewall. Note the VIN stamped into the sheet metal, and riveted tag. These will be transferred to their new locations:



Cardboard template that forms the basis for the aluminium plate that will cover the hollow recess:

 

Update 18th December 2012:

As posted earlier, this 4,2 V8 motor is being paired with an 01E 6-speed manual, from a 2001 Audi S4.

Now, my A4 Quattro originally ran an 01A 5-speed manual. Although installing the 6-speed presents very little problems, the output flanges will not mate up to the Audi A4 Quattro's driveshafts. The reason is simple - size. 108mm versus 100mm. All petrol-engined A4 Quattro with manual transmission run 100mm inner CV joints, while front-wheel drive models run 108mm. At least the 2.6 is definitely 100mm.

The Audi S4 also runs 108mm inner CV joints, hence its 6-speed manual has matching output flanges. My options are:

* Buy Audi S4 driveshafts with 108mm inner CV joints.
* Buy Audi A4 FWD driveshafts with 108mm inner CV joints.
* Buy Audi A4 Quattro rear differential 100mm output flanges.

I went for the third option.

Audi A4 Quattro rear differential output flanges are 100mm, but the important parts that matter (the splined shafts that go into the differential) are the same dimensions as the 108mm items. So Good old eBay came to the rescue, and I purchased a pair. As I already knew, they were a perfect fit. The only differences are the central bolts that hold them in place. The bolt for the 108mm flanges are too short. So a quick call to Ipswich Audi soon had a pair of the longer bolts winging their way to me, they should be with me before the end of the week.

Once they're here, I can bolt the flanges in place. Pictures below:

Replacement 100mm gearbox output flanges, to match Audi A4 Quattro 100mm inner CV joints:



And compared to the outgoing Audi S4 108mm items:

 

Update 18th December 2012:

Again, as previously posted, after removing the secondary firewall to create room for a large snail at the rear of the engine, I was left with a hollow box section. Now I originally planned to have an aluminium plate cut to cover this recess (I had a cardboard template as a pattern).

After some thought, I had a change of plan. The original secondary firewall was the ideal donor for the steel strip. I didn't even need to use the cardboard template. Where it was spot welded to the box section, there was an ovbious trace, left by the bonding agent. It was a simple procedure to use an electric jigsaw to carefully cut the shape out, and it's a perfect fit. I ordered a mig welder, so will be spot welding the panel in place. Then it's a question of preparing the whole engine bay, painting it gloss black, then the engine and gearbox can be installed. I aim to get it all in this side of Christmas.

Picture below showing the steel panel cut out of the original secondary firewall:

 

Update 23rd December 2012:

Today, I was able to complete welding steel plate over the hollow box section, left after removing the secondary firewall. Turned out pretty good - I welded through the holes left after drilling out the spot welds. I actually started yesterday. All I had to do today, was apply a skim of Bondo, and sand it down.

I started with 60 grit, followed by 80, 120 200, 500, 1000 then finally 1200 fine. This is the rear of the engine bay, which will be mostly obscured by the big V8 motor, so I didn't bother going as fine as 2500 wet and dry. I applied a quick coat of grey primer and called it a day.

Tomorroy, I'll prep the rest of the engine bay, prime the lot, then apply three coats of gloss black. Then the engine and trans can be installed. Pictures of the engine bay: