# Audi V8 engine designs



## iamdaveb (Dec 29, 2009)

Anyone know how many parts are shared between various Audi V8 engine designs?
Specifically:
-Do the 3.7L 40V engines (i.e. D3 A8 AQG, AKC, BFL) share the same block/heads/cams as the 40v 4.2L (i.e. B6/B7 S4 ) Are any parts interchangeable?
-Do the 3.7L 32V engines (i.e. D2 A8 AEW, AKJ) share the same block/heads/cams as the 4.2L 32v (i.e. D2 A8 ABZ, AKG or D2 S8 AHC, AQH)? Are any parts interchangeable?
-Are any parts interchangeable between 32v and 40v V8 engines? I.e. can you put a 40v head on a 32v block? Can you put a crank from a 32v 4.2L in a 40v 4.2L? Stroke is different, by 0.2mm which leads me to believe the answer to this is "no".
-Are any parts interchangeable between FSI and non-FSI 40v V8 engines? I.e. cylinder heads, blocks?
-I know the 40v 4.2L found in the S4 has nikasil cylinders which can be challenging to work with. Do the earlier (D2/D3 pre-2004) engines use "traditional" nodular iron sleeves or nikasil like later engines?
-Do the 3.7L 40v engines that came in FWD A8s share the same bell housing as the 4.2L 32V V8s that came in the Quattro A8s of the same year?
-Were FWD A8 engines mounted transverse or longitudinally? (I know 1.8T was mounted both ways on B5 platform)
TIA.



_Modified by iamdaveb at 11:06 PM 12-30-2009_


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## jackyltardvaark (May 30, 2005)

*Re: Audi V8 engine designs (iamdaveb)*

To answer your question is NOT really
32v parts are 32v parts, some 4.2 blocks are simalr as 40v but not the same
T-belt 40v motors have two blocks, RS6 and the rest. RS6 has a large bell housing bolt pattern than others, and uses a 10bolt flywheel instead of 8
B6/7 40v motors are completely different due to timing chain design
FSI motors are there own setup as well, but do share some parts inside


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## iamdaveb (Dec 29, 2009)

any idea on when the switch from "traditional" iron sleeves to nikasil happened? I know the 04+ 4.2Ls are nikasil but what about the 3.7L FWD and 4.2L found in the D2 A8?


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## 32vquattro (Aug 10, 2008)

*Re: (iamdaveb)*

Audi never used nikasil blocks on any of there v8 motors


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## iamdaveb (Dec 29, 2009)

alusil then... anything other than "traditional" iron sleeves. What I've been reading suggests the later FSI V8s use aluminum sleeves with some kind of coating. This would make the motors rather unfriendly to traditional forged pistons, or at least require careful choices of alloy for piston material and ring. I'm looking to find a block I can stick a set of forged pistons in without worrying about.
For reference:
http://www.kspg-ag.de/pdfdoc/k...e.pdf



_Modified by iamdaveb at 9:29 PM 1-18-2010_


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## monkeytronic (Oct 5, 2009)

*Re: Audi V8 engine designs (iamdaveb)*


_Quote, originally posted by *iamdaveb* »_-Were FWD A8 engines mounted transverse or longitudinally? (I know 1.8T was mounted both ways on B5 platform)

All A8--as well as all A4 (including the B5 Passat) and all A6--engines are longitudinal without exception regardless if FWD or AWD.


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## Dub Doctor (Jul 17, 2009)

*Re: Audi V8 engine designs (monkeytronic)*

I'm with you, looking for a 40v V8 with an iron block to build... With the available bulletproof I5, it doesn't appear that many people are building the V8 motors for boost. I'm only seeing the motor being built to get stuffed into supercars and the companies doing that are hush-hush.


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## franque (Jul 12, 2008)

*Re: Audi V8 engine designs (Dub Doctor)*

Yeah, Audi never made an iron block V8. Sorry! If you want to build an Audi V8 for boost, the limits have not really been tested, but I know from this thread: http://www.motorgeek.com/phpBB...=5573 that relatively stock, the V8s are good for 500+hp.


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