4.2 engine compatibility for b6 S4's

[Brandywine050]

I have an 04 s4, I have found an engine with 74k in it from an 05. The supplier doesn't know if the specific differences between the 2 years. But said it possibly wouldn't work wih my vehicle due to the vin split. Any ideas on whether or not it would work and what the specific differences are?

[Street Nasty]

No difference.

[nath]

if its a bbk engine code then it should fit no matter what year

[ajsaudi]

I had the same question I made a thread about some months back. The only thing that might be different is the alternator there's a split for that.

http://www.audizine.com/forum/showthread.php?t=511288

[-C5-]

will a 4.2 A6 engine out of a C5 (belt driven) work in a B6 S4?
if it was direct swap, it would save the headache of the dreaded timing chain problems.

[BCsniper]

if its a bbk engine code then it should fit no matter what year

our engines are BHF.


apparently the BBK was an offering over in Europe, hence why this answer came from a brit

will a 4.2 A6 engine out of a C5 (belt driven) work in a B6 S4?
if it was direct swap, it would save the headache of the dreaded timing chain problems.

no a belt-driven V8 wont work (there was a reason they designed the chain driven in the first place).
It is too long by about 3" I believe. You may make it work by moving a bunch of stuff around, but I wouldn't even start considering doing it. The finished project would be something like the LS swapped RS6 over on Motorgeek.com where the whole engine had to be moved back, the axles are now at an angle, a whole new tubular frame had to be made for the front, and I think he may have even cut out part of the firewall.

[-C5-]

no a belt-driven V8 wont work (there was a reason they designed the chain driven in the first place).

they should have tested it for a few years prior to releasing an engine that has catastrophic timing chain problems and failing plastic parts in the timing chain.

[BCsniper]

please just stop


if you don't like your car get rid of it.




as to the OP, tell you mechanic that you can get any BFH 4.2 motor starting anywhere from '04 up to what was the last B7, '08?

the only issue as others have stated is that the early motors got a Delphi alternator and the new ones have a Hitachi and the coolant tubes are in different spots. This isn't really an issue since you can buy the tubes so that you can use the newer (and better) Hitachi alt.

[-C5-]

if you don't like your car get rid of it.

so i can pass the headache over to someone else and ruin their checkbook? lol.
im fine with my two cars. im speaking about audi's new engines.not the old ones.
apparently my 12 year old engine can outlast a brand spankin new one.

[ozo101]

i have a 2006 engine in my 2004, same thing , oh is for sale by the way 70k miles

[Brandywine050]

I have found another engine since the last deal fell through. It's supposedly from a 2009 s4. Will this work?

[Axel-]

I have found another engine since the last deal fell through. It's supposedly from a 2009 s4. Will this work?

Not sure if serious...

[Axel-]

so i can pass the headache over to someone else and ruin their checkbook? lol.
im fine with my two cars. im speaking about audi's new engines.not the old ones.
apparently my 12 year old engine can outlast a brand spankin new one.

Did you ever end up passing statistics in school?

[Brandywine050]

Not sure if serious...

Unfortunately, yes. I though 09+ was b8 but the salesman I'm talking to is absolute with his decision.

[Axel-]

Unfortunately, yes. I though 09+ was b8 but the salesman I'm talking to is absolute with his decision.

He's a salesman. He'll say anything to sell his product. A B8 has a completely different engine than a B6/7. Not even the same amount of cylinders :)

[Tech/Sales@JHM]

I have found another engine since the last deal fell through. It's supposedly from a 2009 s4. Will this work?

2009 Audi S4 Cabriolet?

[Axel-]

2009 Audi S4 Cabriolet?

Good point, I guess the 2009 cabriolet was still a v8.

[AudiA4_20T]

no a belt-driven V8 wont work (there was a reason they designed the chain driven in the first place).
It is too long by about 3" I believe. You may make it work by moving a bunch of stuff around, but I wouldn't even start considering doing it. The finished project would be something like the LS swapped RS6 over on Motorgeek.com where the whole engine had to be moved back, the axles are now at an angle, a whole new tubular frame had to be made for the front, and I think he may have even cut out part of the firewall.

It actually would fit fine, everything else could be a pain. Check out what the B5 guys do, you just need to cut the core support a little and toss some electric fans on the front. Timing belt motors are $1000 all day every day, wouldn't be a bad swap. As far as axles go, I have no idea why everyone has this pre-conceived notion that the transmission moves when you do an engine swap.... Why? Why would the trans move? Engine bolts up to trans, goes forward another few inches.

Wiring on the other hand would be similar to the 2.7T B6 swap, which most people don't get. They'd need to make a jumper harness between the two since the C5/B5 plugs are not plug and play into the B6.

A/C would also be a pain, 2 different systems.

Is it worth it? Not for most - overall might be cheaper but at the expense of some custom work

[cheetah993]

It actually would fit fine, everything else could be a pain. Check out what the B5 guys do, you just need to cut the core support a little and toss some electric fans on the front. Timing belt motors are $1000 all day every day, wouldn't be a bad swap. As far as axles go, I have no idea why everyone has this pre-conceived notion that the transmission moves when you do an engine swap.... Why? Why would the trans move? Engine bolts up to trans, goes forward another few inches.

Wiring on the other hand would be similar to the 2.7T B6 swap, which most people don't get. They'd need to make a jumper harness between the two since the C5/B5 plugs are not plug and play into the B6.

A/C would also be a pain, 2 different systems.

Is it worth it? Not for most - overall might be cheaper but at the expense of some custom work

It still wouldn't physically fit in the engine bay. The engine is actually longer then the BHF engines. They designed this 4.2 specifically to fit in the tight clearences of the B6/B7 chassis and the timing belt driven 4.2 will simply not fit in the engine bay.

[Brandywine050]

2009 Audi S4 Cabriolet?

Is this the last model with the 4.2 v8?

[Tech/Sales@JHM]

In 2009 Audi continued the S4 4.2L with the Cabriolet. 2010 is the first year they started with the 3.0T S4

[AudiA4_20T]

It still wouldn't physically fit in the engine bay. The engine is actually longer then the BHF engines. They designed this 4.2 specifically to fit in the tight clearences of the B6/B7 chassis and the timing belt driven 4.2 will simply not fit in the engine bay.

yes but it would. The B5 guys are swapping them in left and right.

[AllanElliott]

Just jumping in here some of you guys may have an answer for me.
I have an early 2005 s4 the b6 and my engine wiring harness isn’t in the best shape.
Question 1 which donors are “ plug and play”?
Question 2 what about the Ecu under the hood?
I found a few possibilities for a replacement.
Mine 2005 b6 s4 4.2 base

Donors 2004 b6 s4 cabriolet 4.2
2006 b7 s4 base 4.2
I’m unsure on compatibility first time doing this and I would like some creditable advise.
I.e. you guys.🤔

[Matthewest91]

If you have a b6 you cannot use b7 stuff


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