Passat AAZ Engine Swap: Retrofitting an Old LT 28

Hello.

ich bin 'der neue' in diesem - gut gemachten und mit viel fundiertem Fachwissen angereicherten Forum ! Great job! / Wonderful! / Excellent!


Overall, I can generally keep up with the content of the 'Mechanik' posts, and I'm simply fascinated by the contributions in the areas of electronic engine management and related topics. (That just reminded me of a quote from Socrates...).

Unfortunately, my practical knowledge of diesel engines in the passenger car/light commercial vehicle sector is limited to pre-chamber engines, with a focus on the DB 615 series and Ford 1.6/1.8/2.3 engines. Regarding VW, my technical expertise ends with the 1.6 naturally aspirated and turbocharged engines; I'm not familiar with the T3 and related models.

Now, to my question:

Our stock car team uses an LT-28, an ancient UAZ vehicle, with the infamous carburetor four-cylinder engine. While it drives reasonably well, it unfortunately deserves the designation 'FED' (Fuel Elimination Device).

So, the decision is: diesel engine!

In the past, it was common to modify these vehicles by replacing the original engines with the corresponding 6-cylinder turbo-diesel engines that were originally available as factory options.


The catch: in this conversion, for which parts are now difficult to obtain, you replace almost half the car (logically, the engine and transmission, but also various brackets, the front axle, parts of the steering system, and so on!).

We salvaged a turbocharged diesel engine (AAZ) from a Passat 35i / 5, which was involved in an accident, manufactured in 1995.
'It's almost identical to the built-in gasoline engine, and theoretically, based on the performance data and torque curve we know, it seems to fit quite well with the existing powertrain. Furthermore, a removed LT transmission can be adapted to it in a 'plug-and-play' manner, provided you use the LT friction disc, which has the same dimensions.'

Has anyone here had experience with such a conversion? Is this something that has been documented anywhere?

I am grateful for any advice or suggestions, as I see an opportunity to create an economic boost for our wonderful campervan.

HI,

While not directly related to your question:

The AAZ is not a TDI; it's a TD. There's not much electronics involved, if any at all.

Best regards,

Jan.

I think the gasoline transmission has an overall gear ratio that is too short for the TD.
This will result in a reduction in your top speed.

Hi.

If you're familiar with the TD engine in the T3 (also known as the JX), then you'll also be familiar with the AAZ engine.

sed '/1,6/ {1,9/g}'

The only truly significant difference is the engine displacement (and, if present on the AAZ engine, the immobilizer and the EGR system - not all AAZ engines had these).

Otherwise, both are mechanically controlled turbo-diesel, swirl chamber trekker engines.

m;

Hi,

And is it really supposed to be this easy?
In the Passat model you mentioned, the engine is installed transversely.
'Do the brackets, the transmission, and everything else just fit lengthwise into the LT?'

Hello, first of all, thank you to dieselmartin, Markus H, and wolfi_b for your comments.

Inspired by the wonderful word creation 'TurboDieselWirbelKammerTrekkerMotoren,' and with the help of relevant technical literature, I...
'Now let me examine the engine more closely.' Dieselmartin is right, it's a familiar old design. It's like a JX, but with more displacement and a few extra attachments.

The immobilizer question can be answered with 'yes' (referring to the round coil around the ignition switch?!), but the whole thing seems incredibly simple, only affecting the solenoid valve on the ESP. I managed to drive the donor vehicle without a key, using the 'bad clamp -30- cable from the trailer.'

The question of whether 'AGR' is the correct tag is still not entirely clear, even after research into the community's search function. While the tag 'AGR' yields 729 entries, I didn't find anything that seemed relevant when quickly browsing the posts – at least, not visually.

Does an AGR (Abgasrückführung) system only serve to enable certain emission levels, or does it have other functions? Does the engine power depend on it?

The final gear issue mentioned by wolfi-b is not really a problem for us. Most of the time, the LT is used to tow a trailer carrying racing vehicles. Even when driven solo, it's not driven faster than about 110 km/h due to the characteristics of the seventies-era van chassis (rear-wheel drive with a rigid rear axle).

In addition, there are plenty of used differentials available for the LT models, with many different gear ratios. These differentials were built to last, and they can be easily modified to suit specific needs.


I have two more general questions:

Is there any information available about the thermal behavior of AAZ engines when installed in their original location?
Do the horror stories about self-destructing timing belt pulleys happening at inopportune moments also apply to AAZ engines?

'Thanks in advance for your contributions!'

Antique Turbo-Diesel Swirl Chamber Trekker Engines - Explorer *wide grin*

Hi,

Quote:

Does an EGR system only serve to enable certain emission levels, or does it have other functions? Does engine power depend on it?

That information would have been revealed to you by the technical article about the AGR.

In short, the AGR (Abgas Rückführung) is an exhaust gas recirculation system used for partial load operation – it reduces NOx emissions but increases soot production.

This also makes it clear that it is inactive under full load and, consequently, has no impact on performance if it closes properly.

In your case, the exhaust emission standard probably doesn't matter because the part is likely approved for non-road use. Therefore, you can remove it (although it's not easy because it will leave holes) or, for safety reasons (if it gets stuck), you can permanently disable it by, for example, placing a metal plate between the exhaust manifold and the EGR valve -> use the search function. However, this is only permissible if the changed exhaust emission standard doesn't affect your car. It's best to check with the TÜV (German technical inspection authority) first.

Best regards,

Jan.

fordschrauber1969 wrote:

... I have two more general questions: Is there any information available about the thermal behavior of AAZ engines when installed in their original location? Do the horror stories about self-disassembling timing belt pulleys on the Kühnle valve train also apply to AAZ engines? "Thanks in advance for your contributions!" The antique - turbo-diesel swirl chamber trekker engines - explorer * broad grin *

Enjoy your meal!

The AAZ engine is already running hot, in my opinion, it should have a decent air-oil cooler.
"working on it. An intercooler wouldn't hurt either."

Regarding the KW screw: www.salatoel.kombi.tk. You'll need to search the website for it, I can't provide the direct link.
Not quite all there; Oh yeah, this page is anyway about the AAZ.

Hi, Jockel.