how can I tell an AHU from a 1Z longblock?

[tbones]

hi gang,

I hope everyone's summer has gome well... I've been roadtripping a LOT in SUNNY, my 1Z powered 87 Syncro Westy,through Alaska, Yukon, and BC. as well as WA and OR,
And just drove the PHOENIX back from Maine and the Busses by the Buoy camp out. I guess I'm driving my way out of the pandemic?

so I have a line on a "crate" new motor, and the owner of it doesnt know if it's a 1Z or AHU. is there any special casting numbers, or other ways to tell from a long block? Theres no obvious letter code on the block.

this may be the basis for a new motor for the PHOENIX!

thanks in advance,
Steve

 

[Houpty GT]

AHU is a 1Z after they changed to the 3 letter nomenclature. There is a difference between 1996, 1997, and 1998 motors though, maybe with mid year changes also. You might see the code you are looking for behind the CCV vent pipe.

 

[garciapiano]

The casting for the 1Z is directly above the water outlet, if my memory serves me right.

 

[tbones]

thanks folks.

This is nothing more than a new long block... with no identifying ancillary parts... just a new head and block, with all internals included. I was hoping to find it's an AHU, and has the upgraded pistons.

 

[oilhammer]

It is machined in the flat on the front of the block, right below the head gasket surface. Some replacement engines carry different codes, though. And lots and lots of 1.9L DI engines were made on the same basic block, so it could be one of the Marine or Industrial versions, too.

 

[Steve Addy]

Lots of good information in Wikip about VW TDI engines. Here is an excerpt regarding R4 1896cc

1.9 R4 8v TDI 29-81kW

29 kW (39 PS; 39 bhp) — CDX Volkswagen Marine (10/07->)
55 kW (75 PS; 74 bhp) at 3,600 rpm; 155 N⋅m (114 lbf⋅ft) at 2,000 rpm — CDX Volkswagen Marine (10/07->)
66 kW (90 PS; 89 bhp) at 4,000 rpm; 202 N⋅m (149 lbf⋅ft) at 1,900 rpm — 1Z, AHU
66 kW (90 PS; 89 bhp) at 3,750 rpm; 210 N⋅m (155 lbf⋅ft) at 1,900 rpm — AGR, AHH, ALE, ALH
81 kW (110 PS; 109 bhp) at 4,150 rpm; 235 N⋅m (173 lbf⋅ft) at 1,900 rpm — AFN, AHF, ASV, AVB, AVG

As OH said, the designation will be on the block on a flat machined surface just below where the cylinder head coolant flange is mounted (just below level of gasket) or just above where the oil filter stand mounts to the block.

There are minor differences in the ones that came to the US. I think 1Z was without oil squirters maybe...don't recall specifics.

Steve

 

[garciapiano]

According to RabbitTDGuy from VWDiesel:

1. ALH and AHU pistons are the same. They are quite a bit stronger and less "crack prone" compared to the 1z TDI pistons which are single piece "cast" units.
2. ALH/AHU units are beefier in their construction, are made from a different alloy and also have brass triuons, and thicker ring lands without going to look at my measurements and pictures from the mTDI motor now in the Mk1.
3. There was a slight difference on the 1z motors, with the location of the top ring relative to the AHU variation and the later ALH motor. I believe the top ring on the 1z motors sits higher than the ALH?

1Z does have oil squirters, but they are different than AHU. Supposedly revised with AHU.

More in this thread: https://forums.tdiclub.com/index.php?threads/difference-between-the-1z-and-ahu-engines.302068/

 

[oilhammer]

The early 1Z had different valves and guides, too. 8mm vs. 7mm. There was also a change somewhere with the oil feed to the turbo... early ones had it in the head instead of the oil filter housing.

The thing we have to remember, is that while the old style TDI engine went away from our showrooms midway through the 1999 model year, that engine/engine family continued to be built for a variety of applications (although I am fairly certain the gasoline version went longer). So a "new crate" engine, albeit an old style one like the 1Z or AHU, may have actually been "built" in 2005, and may have acquired some updates since we last saw them here under the hood of a new Jetta.

 

[Steve Addy]

The early 1Z had different valves and guides, too. 8mm vs. 7mm. There was also a change somewhere with the oil feed to the turbo... early ones had it in the head instead of the oil filter housing.

The thing we have to remember, is that while the old style TDI engine went away from our showrooms midway through the 1999 model year, that engine/engine family continued to be built for a variety of applications (although I am fairly certain the gasoline version went longer). So a "new crate" engine, albeit an old style one like the 1Z or AHU, may have actually been "built" in 2005, and may have acquired some updates since we last saw them here under the hood of a new Jetta.

It's still being produced according to what's listed above... the CDX marine version that is.

I also remember some years back there were some 1.9 TDI engines being sold on eBay that were outfitted for something that had to do with cryogenics, whether it was backup generators or some other function, I remember the adapters were still there. How old those actually were I can't say, but it does demonstrate that these were out there being used for other things besides the cars we got here.

Steve

 

[oilhammer]

CDXA is a 75hp engine, CDXB is a low output 40hp variant, and both are the newer style engines (look like an ALH). The last old style engines I could ever find when I was looking for I-shaft bearings' applications was a 1.6L gasser sold in China.

The phase out of the old style engines took a while, and now it may be complete (I have not checked in a while). The newer engines are superior, so I am surprised it took them as long as it did. Cost probably had a lot to do with it. But they had a long track record to look back at to improve upon, and I feel they were careful to keep what worked and change what needed changing. I wish I could find the old new model training info for the 1998 New Beetle. They really went into a lot of detail into the improvements of the new engine family (both the gas AEG and the diesel ALH, vs. the ABA and AHU, respectively). I know block rigidity was a big one. We can thank the Audi guys who were hard at work trying to find out how much power they could safely squeeze out of those early 1.8L 5 valve turbo engines, because that research really led to the new engines' changes. And that is why the low-stressed variants (like the 115hp gassers and the 90/100hp diesels) are so dog gone robust and durable. And really, even the higher output versions like the 170hp gassers and the PD136 are also pretty stout. There is even a 225hp 1.8t, and a 270hp 2.0t.

 

[Steve Addy]

CDXA is a 75hp engine, CDXB is a low output 40hp variant, and both are the newer style engines (look like an ALH). The last old style engines I could ever find when I was looking for I-shaft bearings' applications was a 1.6L gasser sold in China.

The phase out of the old style engines took a while, and now it may be complete (I have not checked in a while). The newer engines are superior, so I am surprised it took them as long as it did. Cost probably had a lot to do with it. But they had a long track record to look back at to improve upon, and I feel they were careful to keep what worked and change what needed changing. I wish I could find the old new model training info for the 1998 New Beetle. They really went into a lot of detail into the improvements of the new engine family (both the gas AEG and the diesel ALH, vs. the ABA and AHU, respectively). I know block rigidity was a big one. We can thank the Audi guys who were hard at work trying to find out how much power they could safely squeeze out of those early 1.8L 5 valve turbo engines, because that research really led to the new engines' changes. And that is why the low-stressed variants (like the 115hp gassers and the 90/100hp diesels) are so dog gone robust and durable. And really, even the higher output versions like the 170hp gassers and the PD136 are also pretty stout. There is even a 225hp 1.8t, and a 270hp 2.0t.

I would tend to agree with you about this, but oddly enough the ALH is the only engine I've ever seen with cracked blocks. I've never seen a 1Z or AHU with a cracked block although I suppose there were some.

The 225hp 1.8t was awesome, and wasn't there a 240hp as well? The 2.0t OTOH was a bucket of ****e that's caused at least 5 years worth of VW cars to be utterly worthless, Mk5 Golf / Jetta and B6 Passat cars with 2.0t are just time bombs waiting to happen.

Steve

 

[tbones]

thanks all,

I cant get the 4 pics I have of the long block to upload!

The part number on the block is: 028103021AF

does that help any?

thanks again all!

Steve

 

[Steve Addy]

thanks all,

I cant get the 4 pics I have of the long block to upload!

The part number on the block is: 028103021AF

does that help any?

thanks again all!

Steve

I found this online, it helps explain where to look for the engine code. The location is easy to discern with this photograph. The example isn't a TDI but all VW 4 cylinders use the same location IIRC.

Steve

 

[oilhammer]

Mmmmm... JH engine... the solid lifter big valve 1.8L GTI engine.

The part number above just denotes it as an early TDI, which we already knew. Both the 1Z and AHU would have many of their engine components' part numbers starting with '028-103-xxx'

 

[Zak99b5]

Mmmmm... JH engine... the solid lifter big valve 1.8L GTI engine.

Don't forget GLi as well! Love me some CIS.

 

[oilhammer]

The scro's had them, too. As did a few of the Cabriolets. But those were saddled with more weight.

 

[tbones]

UGH! FInally able to upload the pix I have... does this help any?

Thanks All!!!!

Steve

IMG_1912.jpg

forums.tdiclub.com

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forums.tdiclub.com

 

[oilhammer]

Yep, those tell us what we already know: it is an early type DI diesel block.

The flat part that has the surface rust on it needs to be carefully wire brushed off to see the engine code. Sometimes they can be hard to read, but that is where it would be.

 

[Steve Addy]

Yep, those tell us what we already know: it is an early type DI diesel block.

The flat part that has the surface rust on it needs to be carefully wire brushed off to see the engine code. Sometimes they can be hard to read, but that is where it would be.

Are you sure about that? I'm looking at the valve cover and the injector ports and 1)not seeing the waves in the VC on 1Z/AHU nor 2) am I seeing the injector hold down bolt holes.

This looks like a late 1.9 IDI engine (AAZ) to me. Am I wrong here?

Steve

 

[oilhammer]

DOH! Yep, you are correct. The glow plug holes are down low.

That is neither a 1Z or an AHU. Possibly an AAZ or similar.

 

[Steve Addy]

DOH! Yep, you are correct. The glow plug holes are down low.

That is neither a 1Z or an AHU. Possibly an AAZ or similar.

Yep...that's probably one of those 1.9's IDI's that was sold out of Parts Place Michigan years ago. They may still have them now, IDK. I just remember them getting in a bunch of those from some source at one time back around '08 maybe?

Steve

 

[tbones]

A picture is worth a lot of words!

(what did we do before pictures... talk more?)


Thanks everyone problem solved! I'll kindly let the owner know

regards.
Steve

 

[oilhammer]

Obviously you cannot use it, and it is just the long block, so you would need all the stuff to even make it run.

That said, I had a guy who had a converted AAz engine in a Vanagon, and it ran pretty good and was simple and reliable. They are 75hp, which is more than the air cooled (70) but not quite as much as the 1.9L waterboxer (87).

 

[tbones]

Hey Oilhammer,

thanks but after 4 1.6 4 motors inthe Phoenix, (my 82 diesel Westy) I'm FINALLY ready to move up to a TDI, and really hope to find an low mile AHU to start with... hence my excitement over this long block

 

[ToddA1]

As noted, VW has been putting markings there for ages. That’s where I pulled the 1Z code from, last night.

And all this time I thought the Jetta TDIs were all AHU… learned some new.

-Todd

 

[TDIMeister]

Yup, not a TDI. Move on.

 

[Steve Addy]

As noted, VW has been putting markings there for ages. That’s where I pulled the 1Z code from, last night.

And all this time I thought the Jetta TDIs were all AHU… learned some new.

-Todd

Yep...I would venture a guess that all 96 / 97 B4 and all 97 Mk3 were 1Z. My 97 Mk3 is 06/97 production so it's fairly close to the end for that model year. I don't know that we'll ever find out much about the switch, even in the parts catalog it shows AHU for 97 with nothing for 1Z in the Mk3. For B4 the parts catalog lists 1Z / AHU and AFN but I think that's just the European application that they've substituted for North America without actually caring about any of it...lol

Stefe

 

[oilhammer]

My '98 Jetta had 1Z on the build tag in the trunk, and AHU on the block in the engine under the hood. From the factory. I think quite a few of them did. I really think it was just a change that VAG did when they changed from 2 to 3 digit engine codes. And it was quite odd that they even had a 2 digit code left in 1997 anyway, as a couple years before they had switched the rest to 3 digit. Even my 1993 Eurovan, built in June of '92, had a 3 digit, as did the diesel option that Canada got. And the standard issue gas engine sold alongside the 1Z was a 3 digit ABA.

 

[Steve Addy]

My '98 Jetta had 1Z on the build tag in the trunk, and AHU on the block in the engine under the hood. From the factory. I think quite a few of them did. I really think it was just a change that VAG did when they changed from 2 to 3 digit engine codes. And it was quite odd that they even had a 2 digit code left in 1997 anyway, as a couple years before they had switched the rest to 3 digit. Even my 1993 Eurovan, built in June of '92, had a 3 digit, as did the diesel option that Canada got. And the standard issue gas engine sold alongside the 1Z was a 3 digit ABA.

Decal vs reality. All the Mk3 trunk decals were wrong about the trans code though too. Every one of the tdi mk3 decals I've seen says CHA for the trans, which is wrong. When the engine changed to AHU the decal still read 1Z, so something was amiss in Puebla. The B4 decals specify the 1Z with the CTN which is correct.

If in fact the AHU was just a recoded 1Z I could see it being this way maybe, but for VW to not specify even in the parts catalog anything but AHU for Mk3 is a little odd I'd say, especially when they were listing all 3 for the B4.

Steve

 

[oilhammer]

It is mostly a non-issue, as there really is no fundamental difference anyway. They scanned the barcode on the left front frame rail tag as it comes down the line.... it is all computerized. Each assembly and subassembly gets scanned, and since the Brussels' plant had already shut down I suspect the engine code change happened afterwards but they were still building the dickens out of the A3s in both the Wolfsburg plant and the Puebla plant.

The '97 B4s actually dropped the base ABA engine a couple months in because they did not want to allow for any more to be exported (that engine was built in Mexico, and they shipped them BACK across the Atlantic to the European plants). They already knew the B4 was going away, and the Emden plant was already retooled and spitting out B5s. 1997 Passats were not very common here compared to the 1996 model. Partially because they were just not a car many Americans were going to buy, but partially because production had already fizzled out.

I was working there then. I was waiting for the 1998 Passat TDI, which they kept telling us were coming.... and they never did. I ended up with a '98 Jetta TDI as my consolation prize.... which wasn't a bad car for what it was, really. But when my chance to get a B5 with the diesel under the hood finally came in 2004, I grabbed one (wish I'd have grabbed two now). I still have the one I got at least! Too bad they only imported the pedal-deficient ones.

The B5 went on to be SO successful that they had to start assembling those in other plants, too.