Head gasket failure, or worse. 3.6PT

Shame on my head,

but I'm not sure if the ECU/TCU is mirrored as well, as the fuse and relais box is. It is generally located underneath the steering wheel (just remove the cover and you should see it).

Thomas Müller here in the forum should exactly know where to find it as he had two RHDs stripped down already.

Bastian

I found them!
Up in the outside corner, above the fuse and relay box. I sort of expected them to be more prominent. There was some rag in the way, which isn't detailed on the service manual. I think someone had a spillage and left it in there for clean up!

Next I shall need to track down some wiring diagrams. If anyone has any about, I would appreciate it.

OK. A couple of observations and a few more questions.

I am close to the point where the block can come out. Once I've undone the harmonic damper that is. I haven't the time or funds to get the correct crank locking tool, So, I have a plan to utilise the tool for my ur-quattro. with a couple of mods.
Watch this space.

Block to gearbox/housing bolts. 8 of these pesky little sods. the 2 at the bottom, behind the front subframe are not so easy to get to. I ended up dropping the front of the subframe an inch (25.4 of those metric things)
and lifting the block a little to access them. are these normally difficult to access, or have I missed something. certainly the engine mounts are showing signs of compression, but I'm not sure that's the whole story.

The ring gear is missing 2 teeth; not adjacent, separated by 1 good tooth. My guess is that someone has used the ring gear to stop the crank from turning while undoing the damper. Does the ECu count flywheel teeth as part of timing, like the ur?

When it all goes back together, I won't have the normal audi alignment tools for timing belt. I'm sure I am not the first, and given some of the odd things I've found with the engine, I don't trust the timing cues that I have.
So, some detailed settings for static timing would be appreciated.

ie. TDC is #1 at top, with TDC on the pulley at top. However, this pulley has a couple of conflicting markings- V notch on the front, and numerals slightly obscured by rust and not so legible.

Hi,

you could try to get the timing utilities for the belt from your local Audi dealer. Usually they have it and if they are nice, the give it to your for little or no money for a day or two. I would ask!

You are right, the teeth are important for the ECU. It is a very interesting fact that it still seems to work without troubles even though you lack some teeth. It is also true that a lot of people are so stupid that they use the flywheel to get the required force to open the crankshaft bolt in the front. That, by the way, caused a major breakdown to my 220V on my way back from Sweden some years ago (yes, I also was that stupid). You can buy the other part of the flywheel without having to buy the whole thing, as war as I know. I'd think about exchanging it, even though it still runs.

It is also common that the engine mounts wear out over time which first causes strange noises and vibrations and second causes troubles when working on the engine without removing the front. So that's probably a reason.

HTH

Bastian

In Antwort auf:

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(25.4 of those metric things)

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Millimeters -> shortcut mm
or
Centimeters - shortcut cm (2.54 cm)

Well, after some searching of the internet, I have enough information for the mechanical timing, so that is good news.

Experience is gained by learning from mistakes as well as successes!.

My guess with the ring gear is that there is sufficient tooth profile to give a signal. And that the broken teeth are not adjacent, then any signal anomaly is not so great. It's essentially the same principal of detection as ABS teeth on drive shafts, and they generally work under much worse conditions.

A flywheel/ring gear is not so expensive, new. And ordinarily, I would just replace it without thinking about it. But I have to keep in mind the mounting cost of parts required to keep this engine viable, compared with buying a short engine.

Hi,

the only thing is that you'll always have to unmount whether the engine or the transmission in order to be able to change the flywheel. Hence, I'd change everything in there possible to be changed easily and not being too expensive whenever you get the chance to do it. Inlcuding all the seals a.s.o.

Bastian

The engine is nearly ready for machining. Stripping the whole things has revealed a few other interesting findings, and one new disaster. Centre main bearing has picked up on the crank journal.

So, not so good!

After all that, the block is effectively dead. Economically.

In addition to the head face damage, the main bearing damage on the centre bearing includes another crack in casing. Repairable? Maybe, but it would ned a line bore process, which just makes it economically not viable.

At least I've found out how to get a V8 front end apart.

So, now I have to decide what to do with the rest of the car. Rolling chassis, 1990 V8. Just wanting a new engine.

Of the engine, the following are salvageable-

Induction system
Exhaust manifolds
Alternator,
distributors
Heads complete
Oil pump (was showing good operating pressure)
PS pump
Air con compressor

These bits damaged-
Block, 2 cracks, and head face damage
Crank- main bearing journals 3(very bad) and 5(light scoring)
Ring gear/flywheel/flex plate 2 teeth missing


So, options-

Buy a short 3.6PT engine
Buy a complete 4.2ABH engine

If yo by a short engine, you can look for damages.
If you buy a complete Engine you do not know what the pre-owner did with the engine.
You can be lucky an find an well maintained engine or a more worse engine than yours.

Sadly, my options are limited here. There's not so many engines about here, and they are generally not well known.

I have an option of a 4.2l ABZ engine, but not sure if it will direct fit. I see it shares some components with the ABH. It's a working engine, from a 2000model A8.
Am still awaiting more info on compatibility.

There are more engine options in germany, but carriage costs to the UK would likely make them non viable.
Maybe I should just scrap the car?
Which is a shame, as the rest of the car is generally in good shape. And I am most of the way through the hard work on the car, having stripped the engine out.
An ABH 4.2 is available, minus the heads. So I may look into that.

Watch this space.
And if anyone is aware of a good engine coming available, either 3.6 or 4.2, then let me know.

I do not know the details to run a ABZ Engine with the harness oft the PT, what has to be changed.

But do not scrap the car.

Dealing with my engine issues.
The big issue here is mechanical.
Electrically, much can be achieved with what already exists.

I would want to use the ABZ motor in place of the PT. If I could get an ABH engine, this would be better. But they seem to exist only in Germany, cost a fair amount, and then there are the shipping costs. My german sucks, to use american parlance.
It is a fairly well supported opinion that the ABH will slot right in where the PT should be. Electrically, there is little to change. ECU program and fuelling being the main concerns, which have been addressed before.

So, mechanical considerations of fitting an ABZ-

Will it mate up with the existing gearbox?
Will I be able to use the Engine mount brackets from the PT?
A fairly simple necessity. I cannot go changing all the drivetrain components just because the engine is dead.
I cannot get into a project of designing or adapting engine mounts, gearbox bellhousings, etc. It needs to mate up with the gearbox as it is now. And mount using existing engine mounts and brackets.
Anything else is simply too great an expense, and an ABH engine from Germany would become a better financial option.

Will the intake manifold fit?
Basically, for the same reason as above, I cannot get into redesigning the intake, or modifying it. The intake from a PT will bolt to an ABH. Will it do likewise with an ABZ?

Will the Alternator, AC compressor, and PS/Hydraulic pump fit.
Again. The components from the PT engine are in good working order, So I would like to reuse them.

At the end of the day, there are a great many components shared between the PT/ABH/ABZ engines. So it is a fair, but unproven, idea that the block didn't dramatically change.
I suspect that the answer to many of these questions is yes. But I have no concrete proof.
If anyone knows a friendly breakers yard where these components could be swapped around to determine, that would be fantastic.

Under other circumstances, I would actually have the car on stands, partially stripped, and simply buy in an ABZ engine to find this information myself. But this is not a practical option at this time. More's the pity.

I'm with you Mario. I hate stripping perfectly viable cars just because of a single(albeit major) components failure. A badly accident damaged shell, or one that has been allowed to rot, are pretty much the only reasons that I would strip a car, personally.
I know of 2 V8s being stripped. 3.6 and 4.2. One has accident damage that made it uneconomical to repair, but not impractical. The other is a later model, and was pretty much fully serviceable. But was partially dismantled by people who didn't understand what they had sitting there. So, there is an ABH engine, in pieces, and no way beyond stripping it and checking it, to determine if it is viable.
If I had space and time, I'd buy both of them now, and in less than a year, 2 good V8s would be running from the 3.

Mechalicallythe ABZ should fit, but i do not know, if there is a chance to fit the PT Distributers in the ABZ heads.
AFAIK the ABZ has for each Zylinder a singel Ignitioncoil.

Maybee yo cann look out for a AEC Engine from the C4 S6,
this one wil fit with only changing 2 temp. sensors. AFAIK

I dont know who did it but sombebody swaped a complete drivetrain with engine from a S8 into teh V8

The S8 conversion was doen by a finnish chap. I already emailed him, but no reply yet. Early days.

I think 034 do parts for a coilpack conversion on the earlier V8s, so that would be less of a problem.
I've been offered a complete PT engine for £700 delivered. So I may well just opt for that. The main issue now is speed of putting it together again so that it is useable over the winter. I'll leave the ABZ project alone for now, unless more concrete information comes up.

It would be good though, to establish whether it is practical to swap the engines. This would maybe provide more options for people in the future.