How to determine block type by the serial number.

[jibberjive]

Through past threads we have pretty well determined that the block type (early block with the weaker main webbing [part number 078 103 021 AE, or just 'AE' for short] or the late block with the thicker main webbing [part number 078 103 021 BF, or just 'BF' for short]) can be determined by the easily visible 'serial number' on the top-front of the engine (see marking V5 in the picture below for the serial # location).

It stands to reason that Audi switched over from the old block casting to the newer casting at a single defined point in time, and that there would likely be a corresponding block serial number for that switchover point (lets call it the 'switchover serial'). Above the switchover serial the block would be the late block and below the switchover serial the block would be the early block.

So far, with the data that a couple of people have shared from their motors, the closest we bracket we have to determine the switchover serial is that if your serial is below serial # APB 013355 then your block is likely an AE block, and if your serial is above serial # APB 018188, then your block is likely the later BF block.

To help make the bracket smaller and close in on the single switchover serial (and to see which year and model of cars likely have the stronger BF block), it would be awesome if some people would contribute their data from their engines.


-- If you have personally verified whether or not your have an early AE block or a later BF block, please contribute your data on the engine in the format below. I will add all of the data to this first post, sorted by serial number, and we will be able to hone in on the switchover serial --


CURRENT SWITCHOVER BRACKET: below serial # APB 013355 is AE block, above serial # APB 018188 is BF block


Existing Data List:

• [YEAR], [MODEL], [BLOCK], [SERIAL], [LINK]
• 2000, A6, AE, APB 009352, LINK
• XXXX, XX, AE, APB 013355, LINK
• XXXX, XX, BF, APB 018188, LINK
• 2000, S4, BF, APB 021858, LINK
• XXXX, A6, AE, APB 029295, LINK (* doesn't follow trend)
• XXXX, S4, BF, APB 032134, LINK
• XXXX, S4, BF, APB 041882, LINK
• XXXX, S4, BF, APB 047613, LINK
• 2002, A6, BF, APB 061151, LINK
• LINK

Part Number:

Passenger side next to A/C Bracket.




Valley Markings:





PLEASE COPY AND PASTE YOUR ENGINE'S INFORMATION IN THE FOLLOWING FORMAT:

Donor Car Year:
Car Model (S4/A6):
Block Part Number (AE/BF):
Serial Number (marking V5):

[AudiTechS4]

hate to throw this in the loop and mess up your bracket but here is mine , guessing your looking at apb blocks though so let me know if you want me to erase this

a6 bel ( unknown donor year)
078 103 021 BF
011699

[jibberjive]

Great contribution. This isn't limited to APB, I'm looking for BEL as well, so thanks.

[y3ti]

Donor Car Year: Unknown
Car Model (S4/A6): S4
Block Part Number (AE/BF): 078 103 021 BF
Serial Number (marking V5): 47613

Donor Car Year: Unknown
Car Model (S4/A6): S4
Block Part Number (AE/BF): 078 103 021 BF
Serial Number (marking V5): 41882

Donor Car Year: Unknown
Car Model (S4/A6): S4
Block Part Number (AE/BF): 078 103 021 BF
Serial Number (marking V5): 32134

Has anyone brought up that there are potentially 2 different BF blocks? I haven't seen it mentioned anywhere on here before.

[WEBER]

Donor Car Year:UNKOWN
Car Model (S4/A6):A6/Allroad
Block Part Number (AE/BF):078 103 021 AE
Serial Number (marking V5): 029295

[FlyboyS4]

Donor Car Year: 2001.5
Car Model (S4/A6): S4
Block Part Number (AE/BF): 078 103 021 BF
Serial Number (marking V5): 031011

[julex]

Haven't we already established that REAL way to tell if it is "BF" or not is to look next to power steering pump and see if you can spot "BF" markings on the block. My 2001 allroad came with block stamped "078 103 021 AE" on its side but with "BF" next to pump and definitely BF style webbings which I myself verified when it was built.

[jibberjive]

Haven't we already established that REAL way to tell if it is "BF" or not is to look next to power steering pump and see if you can spot "BF" markings on the block. My 2001 allroad came with block stamped "078 103 021 AE" on its side but with "BF" next to pump and definitely BF style webbings which I myself verified when it was built.

I was unaware of your thicker main, non-BF part number block. As far as the BF stamp next to the PS pump, my BF part numbered block didn't have that, but was BF part # and thicker mains (and this serial number tracking down helps for blocks like mine, which are missing that marking). So that apparently makes 3 'BF' iterations then ha.

Either way, if we can track it down to a single serial number (or figure out that a single switchover serial number doesn't exist, depending on the data), that is a quick surefire way to tell by the serial number, which isn't hidden under anything.

[jibberjive]

Also, it looks like the serial numbers did start over with the BEL, so we should probably define the serial number (marking V5) in the format 'APB XXXXXX' or 'BEL XXXXXX' to avoid any confusion. I'll correct the ones I input soon.

[jibberjive]

Donor Car Year:UNKOWN
Car Model (S4/A6):A6/Allroad
Block Part Number (AE/BF):078 103 021 AE
Serial Number (marking V5): 029295

Yours is the only one that disrupts the hypothesized trend so far. Just to double check, how confident are you that the engine part number ends in AE? (just as an aside, I have seen some blocks where it was tough to tell the difference between the AE and BF marking at the end of the part number)

Haven't we already established that REAL way to tell if it is "BF" or not is to look next to power steering pump and see if you can spot "BF" markings on the block. My 2001 allroad came with block stamped "078 103 021 AE" on its side but with "BF" next to pump and definitely BF style webbings which I myself verified when it was built.

And same question for you, what certainty would you say that you have regarding your part number being AE rather than BF? When the black coating deteriorates, it's sometimes tough to tell.

[WEBER]

Yours is the only one that disrupts the hypothesized trend so far. Just to double check, how confident are you that the engine part number ends in AE? (just as an aside, I have seen some blocks where it was tough to tell the difference between the AE and BF marking at the end of the part number)

Ya I thought it would!! 100% sure. Has all the AE signs, webs and main bolts.






Sent from my iPhone using Tapatalk

[ianwpb]

Donor Car Year: 2001
Car Model (S4/A6): S4
Block Part Number (AE/BF): 078 103 021 BF
Serial Number (marking V5): 019873

Donor Car Year: 2001.5
Car Model (S4/A6): S4
Block Part Number (AE/BF): 078 103 021 BF
Serial Number (marking V5): 044508

[b7_Andy]

I always thought APB blocks were AE and BEL blocks where BF. I have a 2.7 sitting in my garage ready to be swapped into my B7 in the future. I'll have to post up all the block codes when I look at it again, but here's what I know for sure. Came from an auto S4, has the newer style manifold so I've confirmed it's 2001.5 or newer, and definitely is marked as an AE block.


Sent from my iPhone using Tapatalk

[replica_rs4]

Donor unknown
Block part number 073 103 021 bf
Serial number APB 058459

Sent from my SM-N900W8 using Tapatalk

[jibberjive]

Any new blocks to contribute to the data?

[tate182]

Any new blocks to contribute to the data?

I've got 3 2.7ts in my driveway and one in my garage so I'll have some data for you soon

Sent from my SM-G920V using Audizine mobile app

[uponone nogaro]

I have a 2002 tip s4 spare motor im getting ready to build i will check its numbers and casting then post them up

[christianb5s4]

Donor Car Year: 2004
Car Model (S4/A6): Allroad
Block Part Number (AE/BF): 078 103 021 BF
Serial Number (marking V5): 062808

Of note, while assembling this engine we noticed it had an interesting mix of BEL and APB design features internally, for example it took a BEL oil pump.

[jibberjive]

Donor Car Year: 2004
Car Model (S4/A6): Allroad
Block Part Number (AE/BF): 078 103 021 BF
Serial Number (marking V5): 062808

Of note, while assembling this engine we noticed it had an interesting mix of BEL and APB design features internally, for example it took a BEL oil pump.

If it was from an '04, then it was indeed a BEL code engine, right? Why is it surprising that it took a BEL oil pump? (I actually didn't know they were different)

[tate182]

Donor Car Year: 2001
Car Model (S4/A6): S4
Block Part Number (AE/BF): 078 103 021 BF
Serial Number (marking V5): not sure yet

Here's the best pic I could get with my phone at 5% last night


Sent from my SM-G920V using Audizine mobile app

[RocksForsSale]

So serial number is where the ac compressor is?


Sent from my iPhone using Tapatalk

[tate182]

So serial number is where the ac compressor is?


Sent from my iPhone using Tapatalk

No its the v5 marking that's shown the picture in the valley

Donor Car Year: 2001
Car Model (S4/A6): S4
Block Part Number (AE/BF): 078 103 021 BF
Serial Number (marking V5): not sure yet

Here's the best pic I could get with my phone at 5% last night


Sent from my SM-G920V using Audizine mobile app

Sent from my SM-G920V using Audizine mobile app

[RocksForsSale]

Oh ok I was referring to the part number by accident. For the v5, what stuff has to come apart to be able to see this with the motor in all hooked up?


Sent from my iPhone using Tapatalk

[RocksForsSale]

Y pipe, charge pipe stuff enough to be able to see it?


Sent from my iPhone using Tapatalk

[tate182]

Y pipe, charge pipe stuff enough to be able to see it?


Sent from my iPhone using Tapatalk

I don't think so I think the fuel rails and Intake manning have to come off

Sent from my SM-G920V using Audizine mobile app

[RocksForsSale]

TY

[Stinky s4]

So are ae motors are weaker ??

[tate182]

I believe so

[WEBER]

So are ae motors are weaker ??

Not at the power level 99% of us make.

[Stinky s4]

So the question what are the limits of these different engine codes

[landfill]

Also to note it's been found that out of all the variations the strongest blocks are the
AZR & ASJ found in the b5 rs4. Too bad they're not readily available over here.

[jibberjive]

Not at the power level 99% of us make.

So the question what are the limits of these different engine codes

Not to come off as a dick, but in the effort to keep this thread as more of an information repository for this specific part, rather than a discussion on the implications, maybe you could make a new thread to discuss the limits/pro's/con's etc.?

That is a debatable topic, and I'd hate to see this thread blow up into a 20 page discussion thread rather than a short and simple "what is your block number?" thread.

[Stinky s4]

Not to come off as a dick, but in the effort to keep this thread as more of an information repository for this specific part, rather than a discussion on the implications, maybe you could make a new thread to discuss the limits/pro's/con's etc.?

That is a debatable topic, and I'd hate to see this thread blow up into a 20 page discussion thread rather than a short and simple "what is your block number?" thread.

I respect it

[RocksForsSale]

I don't think so I think the fuel rails and Intake manning have to come off

Sent from my SM-G920V using Audizine mobile app

Anyone else confirm this? Would like to see if I get lucky and got a 2000 bf, but chances are I don't I'm told. Fuel rail and intake mani seem farther up from where that v5 shows no?

[RocksForsSale]

From looking at the two pictures I'm guessing the pass head covers the v5...

[tate182]

Anyone else confirm this? Would like to see if I get lucky and got a 2000 bf, but chances are I don't I'm told. Fuel rail and intake mani seem farther up from where that v5 shows no?

If all u want to know is if it's ae or BF remove the a/c condenser

Sent from my SM-G920V using Audizine mobile app

[RocksForsSale]

If all u want to know is if it's ae or BF remove the a/c condenser

Sent from my SM-G920V using Audizine mobile app

I was trying to find an easier way instead of putting it into service mode and doing that. This thread provides the v5 is the easiest way but I'm trying to verify what exactly needs to be removed to get at that serial number. I'm gonna just pick up a bel block and be done with it i think

[b7_Andy]

Is there a certain vin where they stopped making the AE and switched to just BF blocks? I have an 01.5 motor and it's an AE


Sent from my iPhone using Tapatalk

[jibberjive]

From looking at the two pictures I'm guessing the pass head covers the v5...

The passenger head doesn't cover V5. It's at the front of the motor, passenger bank, sticking out inside the 'V', where the head and block mate.

Sent from my SM-G930T using Tapatalk

[Teck09]

Donor Car Year: 2001.5
Car Model (S4/A6): S4
Block Part Number (AE/BF): BF
Serial Number (marking V5): 036109