forum.audiv8.com Foren English Audi V8 Forum Head gasket failure, or worse. 3.6PT

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?

Hi,

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.

Regards

Bastian

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.

Maybee the heads are leaking it self,
because of a crack beween oil or waterport to the combustion chamber?

some pics might be helpful

Pics on their way shortly.

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.

Not a day for celebrations

Gosh! Seems to be really f***d up. Block's death sentence.

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.

Hi,

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!

Bastian

I presumed it was, or a form of, Nikasil. I'd not come across alusil until now.

Damage to the right hand bank of the block

Aehm, what i should see?

Oops
I thought I'd added a label to each-

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.

Thanks for the help

Is the despression "feelable" by touching with the fingertip?
Sure thats a crack? Looks like dirt or a piece of the gasket.

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!

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.

Hi,

ABH has been exported to UK as well, so it would be just a matter of patience. An ABH was auctioned two weeks ago south of London - for _really_ little money (the whole V8, not only the engine). PTs are seen as well from time to time.

If you have the change to get a PT and make a plug and play switch, I'd vote for that. Changes are way higher that you have your V8 back on the streets in near future. Alternatively, if you are still up to an ABH, look at germanautoconnection.com - they have detailed descriptions on how to switch from PT to ABH. But I'd never go for that if I can have the same engine with no troubles.

Bastian

I go with Bastian.

A PT to PT swap is done in a few hours, a converstion can take days.

Get the PT engine and get the car on the street,
if yo still want to make it faster () yo have enough time to find all parts for a conversion.

I even agree with them

Worst case: Spend a few days of your vacancies in Germany , buy a PT and ship it by yourself.

You can find a couple of responsible guys at the huns , selling checked and solid working V8 parts.

In all my searching of the UK, I have found only 2 viable V8s

PT, with 3mths warranty. at £700
ABH, but someone has already taken both heads off, and sold one. So, nearly worthless, given the cost of the gaskets, head bolts and replacement head.

The ABZ option will come later, when time allows.

I have, in this process found 2 cars languishing.
One is nearly complete- Gold. minus one head- partially dismantled engine, but otherwise complete. And supposedly in working order. But the state of the car prior to the head being removed is unclear.
The other car is a donor car, partially stripped, due to rear body damage. Several components, including the engine, have already been removed.

If it were possible, I would be straight over to germany to source an engine, but it's just not practical right now.

If I had the space, both these other cars would be in my possession now.
Timing!

Hi,

shipping is no option? Shipping a (manual) gearbox is around 60 pounds, hence I guess that the engine maybe costs twice as much - still way cheaper than driving to Germany.
Bastian

Mark,

would you like us to look for a cheap PT for you in Germany? If yes, what's the max you can spend (excl. shipping)? Or do you want to find one on your own?

Bastian

Hi Fellas

Thanks for the offer. I have located a PT engine in the UK, £700 including delivery. I just need to coordinate it in between business trips.
If all does not go well, then I'll take you up on your kind offer.

cheers