80V6 Engine Rebuild

[V6quattro]

Nice man! This engine becomes better than new! :corey:

[S2central.net]

356 - before on the right, after on the left - after a quick application of marine clean and maybe 20-30 mins scrunging it with a brush

358 - somewhat of a close up

359 - impressive stuff with one head rinsed and dried

[20vQC]

Like new!! Great job paul

[Tommy200rs]

Here for project comparison purposes some measurements from another engine.

My earlier original cats did not pass any more the mot test. Here is how the AAH cats (from german ebay, cat diameter 100mm) now look like after the fix. Downpipes were also removed with minor modifications. CAT-back part remains original.



edit: the official mot measurement results (old cats /new cats after)
- no major warm-up efforts done and easy pass

2000< RPM
lambda 1.011
CO 0.51 after 0.18
HC 65 after 46
CO2 13.90 after 14.8
O2 0.62 after 0.16
CO correction 0.52 (old only)

RPM 770
lambda 1.011
CO 0.49 after 0.06
HC 139 after 76
CO2 13.80 after 14.9
O2 0.70 after 0.11
CO correction 0.51 (old only)

=> MOT test OK, but flow capability is such that really low HCs are not achieved. Note that engine has been driven a lot (no history available) without any internal service. It will be interesting though to test the new similar S2 cats with 130mm diameter solution and what the results are then at idle.

[Tommy200rs]

the AAH engine is a real beast of leaking oil from different nasty sources like valve covers.

Volvo chemical gasket 1161059 is recommended and an anaerobic Gasket Sealer for Valve Covers, Engine Flanges, Oil Pans, and Differential f- ex.. It is highly recommended for places where the AAH is suffering leaking problems. It is orange/pink colour.

edit:
this anerobic chemical gasket also seems to have a lot of those similar good abilities to metal to matal surfaces or where there is also a gasket in place and stress/oil contamination:

https://tds.us.henkel.com//NA/UT/HNAUTTDS.nsf/web/7376F184F57D5C3C852574650047643A/$File/5188-EN.pdf

Loctite® 5188™

Loctite 5188 is an ultra-tough anaerobic gasketing material with high elongation & toughness even after exposure to elevated temperature (up to 300°F continuous). High flexibility makes it perfect for large, highly stressed flanges. It is designed for use on rigid metal flanged connections, such as gearboxes and engine casings, particularly where minor oil contamination of the flange surfaces can occur. It cures between close fitting metal surfaces in the absence of air and is particularly suitable for use on aluminum substrates where very good adhesion is achieved. It also provides resistance to low pressures immediately after assembly (instant seal). Loctite 5188 was formulated as an improved version of 5127 (otherwise known as 17430).

[macspring]

Re Post 75 &amp; Photo 164,

Paul,

I know you said you probably wouldn't port this engine, but I read recently on another forum that with these engines the match between the head and the inlet manifold is not great and so as you have it apart, it might be worth considering checking the matching of both the inlet manifold and exhaust manifold ports with the head, if it's not too late.

You'll never take it apart to do it again later, as this engine should be very sweet, either way, at this rate.

Looking forward to seeing it / hearing it in the flesh one day.

Kind regards.

[Error404]

nice one Paul, glad you tried the Marine Clean - amazing stuff huh?

[S2central.net]

@david - I will likely check that... Cashflow is hindering progress of course so I'll have time to do some checks like that... Hopefully anyway !

[Tommy200rs]

I did the small fixes to AAH and biggest effect was in changing the cylinder head oil line over pressure valves. Those seem to be too open when old. Now the valvesystem noise is allmost gone. Well it can not make much noise with 12 pcs of valves and hyd lifters...

Also fixed the multifunction sensor to have water temp visible and that revealed that the thermostat is not working properly.

The AAH ECU diagnostics channels are so limited. Channel 00 only available. It looks so 3Bish list. any www link to AAH diag channel info ? ELSA was soooou limited in that area.

Paul,
when is the first burn in day for the AAH ?

[S2central.net]

1st burn day... LOL - I might torch the damn thing and claim it on insurance - JOKE...

I'm trying to collect enough funds so I can buy some decent bearings, piston rings and gaskets... The price of a rebuild fair rockets when you want to do it properly, then add fresh radiator and a new clutch. Most people would just lash it all together, throw some paint on it, fire it up, put it on eBay and never look back.

Here's a question for the V6 aficianado's - is it possible to modify the old block and heads so they can run with the lightweight valve lifters?

Everything I read official from Audi says you cannot put the new/light lifters into an old engine because of modifications to oilways and such. I dont want to be the guinea pig here but just wanted to know if someone else has BTDT.

You are right about the OBD and the lo-tech approach to this 12V engine - if money was no object I would have gone for a 30V transplant... but thats just crazy talk.

The plan/hope is to have the V6 rolling again before winter sets in so I have a chance if I get my act together. Even with all the photos I took I am concerned about putting it all back together as right now it feels like someone else dismantled an engine in my garage and left the parts in boxes all over the place

[Tommy200rs]

Here some old documentary tricks for the ugly AAH engine maintenace. Vacum leaks destroy the fuel economy in any free aspirating engine. In turbo cars the leaks are much easier to spot when driving with boost.

AAH vacum leak areas:
- valve cover breather system, fix that
- throttle valve entry where the rubber entry gasket is too loose in older installations
- there are instructions to put a round electric wire around it and make it tighter
- the trick is that most probably you use too loose wire in fixing that and it still leaks
- overcome that problem and make the turbo pressure test to free aspirating AAH , that will reveal the worst leak spots
- different vacum hoses are also checked in pressure test
- and the final: vacum break booster has mechanical design problem inside and the actuator/release spring deteriorates slowly one gasket and system starts to leak when supposed driving with strong vacum and the consumption should be low (this problem is not so easy to find out)

By doing above fixes It was realized how AAH quattro run low 8L/100km and it is belived that 7.5/100km is possible when driving around 95km/h-100km/h. Testing speed for 8,3L measurement was needle speed 100-140km/h and distance of 300km autobahn driving. Not too bad for the well known thirsty 2.8L V6 engine.