Timing Belt Failure T4 AAB - No ABL Conversion

The cutter is gone .

A 1991 T4 California AAB (2.4 SD, 78 hp) broke down at the Fernpass pass.

First look inside the engine compartment:
- The timing belt on the right side (the important one) is gone.
- only timing belt dust is visible.

He is now located at the VW facility in Reutte.

The colleague who rented the car is back home.

Now that we have the bus back, what should we do?

- Conversion to ABL (1.9 TD - the AAZ sibling)?
- Should the AAB be repaired piece by piece?
- Replace the AAB?

How can I assess connecting rods and pistons?
How can we figure out why the belt failed after 60,000 km?

Greetings.
m;

Quote:

How can I assess connecting rods and pistons? How do we find out why the belt failed after 60,000 km?

Perhaps we should first break it down, or expose it .

Hi,

"Refurbishing is always more complicated than simply installing or repairing the same engine. Especially if it doesn't offer any performance benefits."
"First, remove the head, and then the question of whether to repair or replace the engine will resolve itself."
3. Remove the cylinder head and measure the piston protrusion. If it's even, then the connecting rods are likely okay.

The cause of the bearing crack:
1) Something is blocking it.
2) Some guide rollers are defective, and a piece of the pulley has broken off. This will slowly cut through the timing belt.
3) KW central bolt. Are there any issues with this at AAB as well?

Regards,
A.

jarobaldu wrote:

Hi, 3) KW central bolt. Are there any issues with this at AAB as well? Regards, A.

Normally not, but there was once a modified water pump installed -> different number of teeth, different bearings.
"I had this engine installed in an Audi 80, type 85, and when I did the conversion back then (in 1997), I replaced everything. The VW mechanic said there were problems with the timing belt due to the water pump."

Regards, Mpire.

Hi!

I've also read about that water pump issue several times.

I would like to remove the cylinder head and take a look at the rest of the engine.

Alternatively, an AT cylinder head or a used cylinder head would be possible.

An ABL engine, if it fits, would also be a possibility. They're quite fast, considering their relatively low horsepower.
Perhaps we could also add an intercooler to dissipate some more heat from the system.

You can build a 2.4 TD engine using parts from a 2.5 TDI. It's supposed to have decent power. But first, the van needs to be able to drive again.

DOWNSIZING

The colleague is currently planning a conversion to a 1.9 TD engine.

m;

Hi,

open it up, and then examine or measure it, as already mentioned.

I've experienced this before, and it wasn't that bad.

See here:
Okay, I'm ready. Please provide the German text you want me to translate.

Greetings,
dieter

Hi Dieter,

Sure, the patient will be opened up first.


The colleague seems to be quite interested in the TD .


For now, potential tuning of the ABL is secondary; the primary focus is on the complete conversion.

According to the T4 Wiki, the ABL was also standard equipment in the California model, and the TÜV (German technical inspection authority) indicated that the costs for approval and registration would be relatively low.
Therefore, the question arises as to how much work is involved. We know that you need the motor mount on the drive side and components from the ABL. But what are the critical points during the conversion? Does the entire electrical system need to be completely rewired, or can the existing connectors from the vehicle's existing wiring harness be largely reused by simply changing the connections?
AGR and Oxikat were also not available from AAB... does this pose a problem from this side during the renovation?

The transmission from the AAB can stay - are we correct in that assumption?

If anyone has done this conversion before, it would be great if they could share what the really difficult parts were... and how much time would it take if the work is done in a proper workshop?

m;

Hi!

Okay, I've already replaced an ABL unit before.
(I also have a box of spare parts left over.)

It's already a lot of work, taking the grill out, taking the cooler out.
We used a lift platform for this, and we moved the engine in and out on a rolling cart.

When dealing with a car of that age, expect to encounter rusted screws, which can make repairs time-consuming. You might also need to modify the exhaust system, replace or reroute vacuum hoses, and adjust the water hoses, among other things.

Think about how we're going to deal with the immobilizer; the car doesn't have one.
If you install an engine with WFS, was there anything specific about the fuel injection pump?
Maybe someone here knows something about that.

Steffen G wrote:

Think about how that will work with the immobilizer, the car doesn't have one. If you install an engine with WFS, was there anything specific about the fuel injection pump? Maybe someone knows something about that.

Remove the control unit on the pump and everything will be fine.

The cam is already damaged (and in some places, completely gone!!).

Did the bearing in position 2 overheat/seize, and then cause the cam to break?

How can one identify the actual chain of events }after something has already happened?

m;

Hi!

I don't know what the water pump looks like, or what the remnants of the timing belt look like.

Perhaps like this:
1. Oil drilling.
2. Camshaft difficult to turn/stuck.
3. As a result, the timing belt broke.
4. As a result, the pistons were slammed against an open valve.
5. Broken camshaft.

"The 'remains' look more like 'Bikini Atoll in the 60s'."

Hi!

A timing belt failure looks different; you wouldn't see that kind of debris.

I actually noticed some residue on the tensioner wheel earlier.

In that case, the ZR was only the victim, not the perpetrator.

Update:

The colleague has removed the dead AAB... the "new" AAB is already on a pallet, ready to go.

m;