No turning back now

[Delboy]

Getting stuck into decoke and injector testing.

[Turbo Tony]

Wow! You've been busy!

Good luck with it... get plenty of practice before you do mine!

[Goran]

So was it coked up? Just curious because FSI was one of the major reasons putting me off a D3 S8 (or any other FSI car)

[Delboy]

Well its taken myself and Marcin 3 days of running around and bent over that bloody car scratching, scrubbing, poking, prodding and generally cursing.

If it weren't for him helping it would have taken a lot longer.

Now my car has something like half the mileage of Marcin's but Marcin said his had similar levels of build up.

I know his car had lived on the motorway where as mine spends a lot of its time in the town.

We obviously don't know if either cars have been de-coked before or what impact driving styles has on build up but it surprised me how much there was for an engine that has 75k on it and since my ownership has been looked after well with oil changes every 3-4000 miles.

So we began the whole process by removing the manifold which with Marcins prior experience didn't take too long at all because he knew where the hidden screws were at and how to go about getting them off.

Once the Manifold was out I thought it would make sense to have the injectors pulled and dropped off at a ASNU service centre which for me was Clive Atthowe Tuning, these chaps knew their trade well and if anyone is interested in tuning, rolling road, injector testing etc are well worth a visit.

Removing the injectors is quite easy and just required the rails removing and then rotating and pulling up on each injector to remove it.

We dropped them off and carried on with the carbon clean, first out of the inlet tracts is the plates which sit in there. they looked like this

They were thrown into a tub with degreaser and left to soak over night after most of the gunk had been scraped off



All ten were more or less the same and I was surprised at the build up considering how clean my inlet manifold was compared to Marcins if you remember the Flaps inspection video i posted a while back.

Onwards with cleaning we tackled a bank each to speed things up and all 10 tracts and valves were gunked up, some worse than others but all manky.

I didnt take pictures off all of them as there was no point.

Sorry for the massive pics.

The picture of the cleaned tract and valve is after the bulk of the cleaning, now it looks like its still bad but its actually quite small valves in these engines and the specs of carbon are very small, once you get them like that its scotchbrite and degreaser and lots of poking and scrubbing to clean them up a bit more but they really don't get too much better TBH.

Blasting would be the only way to get them spotless.



During cleaning was informed by Clive that 4 of my injectors were below par and need cleaning to try and rejuvenate them as the spray patterns were less then ideal and IIRC 2 of them were leaking when shut so he went ahead and done that.

They recovered three of them by cleaning so I had to order a new injector along with repair kits for reassembly, these injectors have teflon seals that are meant to be replaced prior to refitting.

I decided to order a new oil separator at the same time, hoping to prevent oil mist from getting in the engine (wishful thinking)

Cost of spare parts

• Repair kits A06E 998 907G £112.86
• INJECTOR A06E 906 036 C £120.14
• OIL SEPERATROR A079 103 464 D £118.88
• MANIFOLD BOLTS AN 911 262 01 £8.78

ASNU SERVICE

• LABOUR FOR SEAL FITTING £33.00
• TEST 7 INJECTORS £70.00
• TEST & CLEAN 3 INJECTORS £105.00
• TOTAL WITH VAT £249.60

The breakdown of the ASNU service is like that because if an injector is good then they only charge £10 each if they require cleaning then its more work.

I asked them to test the new injector also when I went to collect the others to make sure it was OK, I also needed them to fit the teflon seals as special stretching and shrinking tools are needed to do that.

There is a small video in the attachments of some of the injectors on test below.

Once we got them back home it was just a case of assembly, it all went smoothly other than dropping a few things down into engine bay which required rooting around with the borescope inspection camera, and me forgetting to tighten an inaccessible fuel rail pipe.

Once it was all back together this became obvious with petrol ****ing out on application of ignition

Luckily i managed to get away with removing the T piece with the throttle bodies on, a few other bits of pipework and I chopped up a spanner to allow the tightening of the fuel rail pipe.

I don't think i could have coped with removing the whole manifold to tighten one pipe.




Once it was all back together the second time it was time to fire it up and give it a good blast along to the road to clear it out.

Happy to say its running well, any performance gains I hear you ask, well none that i can feel and I did give her a good toeing.

We then took both cars to the local testing ground and did side by side drag runs and there is no performance difference between both cars so we were quite pleased.

Time for a few

Thanks Marcin for all the help greatly appreciated, now you can go back to maintaining your missile

[Turbo Tony]

Well done Del & Marcin, it's great to hear another S8 is being is being treated well. I look forward to seeing the pics.

I noticed a US site recommending essentially a thicker gasket for the inlet and longer bolts to mount it. It' supposed to give you a little more power by reducing heat. Did you do/consider doing that?

I'm an OEM kinda guy but I imagine it would be an easy few extra bhp for those that way inclined.

[Delboy]

I have seen the manifold spacer you mention and no I didn't. I'm oem man too. The spacer is meant to insulate the manifold from heat soak from the block.

But with all the surface area that is in contact compared to the surface area exposed to the heat in the engine bay I really can't see the point.

The site selling it also hasn't proven any gains from fitting it.

Furthermore fitting the spacer marginally changes the inlet tract length which could have a positive or negative impact on performance, but with out dyno runs to back up the claims I'll steer clear.

As to heat we both were messing around last night after some test runs and took some pictures with a heat cam.

[Delboy]

Pics and info added

[Turbo Tony]

Thanks for the pics, Del. Wow, that's a lot of gunk for an engine that's reputed not to be too bad with carbon deposits.

I think you've made up my mind for me, I'll definitely get mine done.

How does the car feel now that it's done? Can you tell a difference?

[mattylondon]

Excellent write up and first class work guys. Hugh respect.

[Turbo Tony]

Apologies, I missed your earlier write up of the feel post carbon-clean.