Finding and preparing a new to me AMF

[Little Dog]

I just pull 90 degrees by eye. I get it close enough. I thought the iPhone was quite novel though.
Undecided on gasket thickness. Not sure about the shells so not yet decided if going new, what I have or the shells from the engine in the car. Once I build up the engine Ill measure the protrusion and decide on the gasket. All I have done since I last posted is clean up. Going to get an engine re-manufacturers opinion on the bore glazing / honing.
I have not yet stripped down the head. Hoping the valve guides will be good so there will be no need for machining.

 

[Bordos]

With the head stripped - what is the condition of injectors sockets ?

I would appreciate if you can take a picture of those.

 

[Little Dog]

With the head stripped - what is the condition of injectors sockets ?

I would appreciate if you can take a picture of those.

There is some wear in there but I think it is consistent with 100k miles. Working on the head next week; I'll post some pictures.

 

[Little Dog]

An update on last weeks progress before I start work on the head.

the block is now a bare casting. Except for a stud and some location dowels, and is clean ready to be taken to an engine remanufacturer for their opinion on the honing.

The pistons are being cleaned, only paint stripper will touch the carbon deposits. Also the rings are not marked on the top side. If you are tempted or need to do this job I recommend the top is marked before the rings are removed, I used tipex. Once everything is clean I will measure ring wear:

The head casting cleaned up quite well. I used Gunk and a domestic steam cleaner:

Next job measure the bearing wear then strip the head. Also, as requested, get some pictures of injector and casting wear.

 

[TFG]

That head cleaning looks great, Phil. For some reason, I’d not thought of using a domestic steam cleaner, which is daft as I’ve got one here with a perfect attachment for that kind of work! Thanks for the prompt. I’ve got to do very similar work on mine in the next few weeks.

 

[Little Dog]

I've taken this picture for @Bordos but I'm no sure what I’m (we now) are looking at. It looks like there are rippling wear patterns on the surfaces that support the injector:

I can't imagine what machining process could produce these ripples so I got the borescope out:

The ripples are on every supporting surface and not looking like consistent machined ripples. To make sense of this I'll get No 3 injector out and photograph the wear and see if it corresponds.

 

[Bordos]

I've taken this picture for @Bordos but I'm no sure what I’m (we now) are looking at. It looks like there are rippling wear patterns on the surfaces that support the injector:

View attachment 117523


I can't imagine what machining process could produce these ripples so I got the borescope out:

View attachment 117524

The ripples are on every supporting surface and not looking like consistent machined ripples. To make sense of this I'll get No 3 injector out and photograph the wear and see if it corresponds.

Thank you for those pictures - the reason I wanted to look at those is to see whether damage from injector movement (as I read they tend to sway).

 

[Joga]

Thank you for those pictures - the reason I wanted to look at those is to see whether damage from injector movement (as I read they tend to sway).

Then you are mostly interested in the cylindrical inner wall surfaces rather than the bottom seat surface I guess?

 

[Bordos]

Then you are mostly interested in the cylindrical inner wall surfaces rather than the bottom seat surface I guess?

Exactly - I was told that after about 150-200 kkm the state of injector sockets is usually so bad, that it is hard to have the fuel lines tight (not leaking into oil).

 

[Little Dog]

Pictures of No3 injector for @Bordos , There is very little if any wear on the clamped side of the injector, just the lower red O ring breaking up:

There is wear on the vertical surfaces of the unclamped side and the O rings are also abraded and not as deep as new:

Could O rings wear be the reason diesel leaks occur? New O rings cured running problems with the 170k miles AMF in the car.

 

[Little Dog]

Last bit of checking before the engine including the head is fully stripped. The cam bearings look well worn and they will be replaced as I had already bought them for the engine that is in the car. Despite the way they look do they need to be replaced?

The manual specifies the radial clearance wear limit 0.11mm. I'll check 1, 2 and 3 as these appear worst worn.

Remove the hydraulic tappets otherwise they push the cam up slightly:

Put cam in position, lubricate with silicone and cut and apply Plastigauge strips.

Tighten down the cam bearing caps. Had to fit the rocker shaft as the bearing cap front screws would not go in. I need to check that separately.

Remove bearing caps and measure radial clearance.

About 0.05mm; so despite the worn surfaces it appears the bearings are within the accepted wear limit. for the same result on the valve guides.

 

[Joga]

Pictures of No3 injector for @Bordos , There is very little if any wear on the clamped side of the injector, just the lower red O ring breaking up:

View attachment 117594

There is wear on the vertical surfaces of the unclamped side and the O rings are also abraded and not as deep as new:

View attachment 117595

Could O rings wear be the reason diesel leaks occur? New O rings cured running problems with the 170k miles AMF in the car.

Very interesting to see as I have one car which I suspect leaks fuel into the oil at the injector and plan to see how to mitigate it. So one oring did have damages when you pulled it out?

 

[Little Dog]

Very interesting to see as I have one car which I suspect leaks fuel into the oil at the injector and plan to see how to mitigate it. So one oring did have damages when you pulled it out?

All three O rings are worn with the lower one breaking down. Ill check the other two injector’s O rings when next working on the engine.

 

[PlasticMac]

Wonder if the O ring damage is down to modern diesel additives?
Is the part number for the current replacements, the same revision as the originals, or maybe the O ring material has evolved over 20 years?
Mac

 

[Deleted member 20348]

Hi,
I expect the wear on the cylinder head injector well wall could be filled by an increase in the cross section of the o-rings.

But an increased cross section may damage the o-ring when fitted?
This applies to my cylinder head I hope yours is in better shape!

 

[Little Dog]

Wonder if the O ring damage is down to modern diesel additives?
Is the part number for the current replacements, the same revision as the originals, or maybe the O ring material has evolved over 20 years?
Mac

I don’t know the answer to your question. When I replaced the seals on my 170k miles AMF I used a Bosch seal kit so didn’t have to get Audi part numbers.
That lower O rings on that engine were in worse condition, they were dissolving. That engine had running problems under load. The engine in this thread ran fine.
Both engines injectors were untouched from the factory and had issues with the lower O ring, the degrading of the rings in the car were 70k miles more advanced. My conclusion in both cases was that diesel had caused the O rings to degrade but I haven't investigated further.
The 170k mile engine has only ever been run on unbranded supermarket fuel. I don’t know how much of what is coming next regarding diesel properties is fact or fiction. The only fuel additives used in this engine have been the occasional shot of low ash 2 stroke oil. The idea there was to protect the tandem pump as in recent years the lubrication properties of diesel have been reduced? Perhaps the fuel also lubricated the injector wells and O rings?

 

[Little Dog]

Hi,
I expect the wear on the cylinder head injector well wall could be filled by an increase in the cross section of the o-rings.
View attachment 117642
View attachment 117643

View attachment 117644
But an increased cross section may damage the o-ring when fitted?
This applies to my cylinder head I hope yours is in better shape!

I need to take a further look in my injector wells, this engine is on 100k miles. When I did this job on a 170k mile engine the injectors were far more worn on the vertical surfaces. My conclusion then was that the well walls could not be worn where the O rings contact. So just replacing the O rings with Bosch parts would do the job. They appear to have done the job.
It would be worth checking for smooth rings of metal in the injector well for standard O rings to seal on before going over size.

 

[kp 115]

I need to take a further look in my injector wells, this engine is on 100k miles. When I did this job on a 170k mile engine the injectors were far more worn on the vertical surfaces. My conclusion then was that the well walls could not be worn where the O rings contact. So just replacing the O rings with Bosch parts would do the job. They appear to have done the job.
It would be worth checking for smooth rings for standard O rings to seal on before going over size.

I’m sure that the prongs should be replaced as a mater of course, I would not be replacing the injectors into the head without doing the seals as the deformation apparent to the seals cross sectional area is very noticeable.

 

[Little Dog]

I’m sure that the prongs should be replaced as a mater of course, I would not be replacing the injectors into the head without doing the seals as the deformation apparent to the seals cross sectional area is very noticeable.

I never use old seals. I’ve added a few words to my comment to provide clarity.

 

[Deleted member 20348]

Hi,
I agree, use bosch injector seal kits or similar brand.
My apologies for moving off topic, you were talking about the lower seals at the tip of the injector unit.
I am graetful for your reply.

Measuring the indentations in the well walls to establish their diameter is good advice.
The shape may not be circlular but the o-ring should accommodate this. I guess viton seals would work in this application if oversize required?
I need borescope to inspect the lower o-ring well wall.
Is it possible the injector body has made the indentations due to a slight sideways force exerted by the hold down clamp?

Hypothetically speaking the lower seal could be damaged right from go. As when nstalling the unit it may not be diven into the injector well evenly.
There is probably mechanics hack to reduce the likelihood of this. Apply engine oil to the o-rings and well walls and gently drift the injector down in stages at the opposite side to the clamp to overcome the well wall ridges?
Your build is fantastic and a great read.
Cheers!