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#2
7th November 2010, 09:59 PM
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Top reference library resource John. Thanks. Added to Sticky.
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Conan (the Librarian) Watch it if you dare Currently, 2000 S8, Merlin Purple, Leather Pack 1, Winter Pack 1, SPAX adjustable suspension, AP Racing 6 pot front caliper, 385mm fully floating disks, EBC Yellow Stuff Pads, Black Diamond grooved rear disks and predetor pads, D2 Doctors Brake Block. 1997 4.2 A8SQ - the Projekt. 12 years and ongoing! 1997 4.2 A8SQ - Ming Blue. Restoration sat waiting; saved from the Scrapyard 2003 C5 Allroad 4.2Q - Cobolt Blue. Towing car. Laid up awaiting manual conversion. 2005 C5 Allroad 2.5TDi FE - Grey - Workhorse. 2015 Q3QS SLine - Daytona Grey. Lots of extras! Long Haired Admirals cutter. Previously 2003 C5 A6 1.9TDI FWD - Loaner from D2 Doctor Lifex 1997 S8 - Ming Blue. Loaned out and written off. I loved that car. My first engine swap after cambelt failure. 1996 4.2 A8SQ - Ming Blue. 178k on a cambelt! Trader's 8. Delivered to A8Parts at Lifex. 2003 2.8 A8SQ - powder blueish. Fill in for a while. Sold on. 1998 1.8T A4 Avant FWD. Ming Blue (there's a theme here), PEX for the 97 S8. And a list of non VAG going back 40 years before I saw the light. 
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#3
8th November 2010, 02:27 PM
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Thanks John! Ive cancelled all my (expensive) magazines - now all you need to do is find that much monthly for us all to read!!
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Confidence is the feeling you have before you know better . . . .  Audi A8 D2 3.7 Quattro Sport 1999 FL - Melange 2nd Place Winner - A8-Freunde Annual German Meet 2012 at Edersee 20" x 9" Bentley GTC Wheels with 385mm W12 Front Discs & Bentley Caliper Covers, Front Lowered on Coilovers, Xenons, Combined DRLs and LED Foglights to modified OEM front fog lamp position, Alcantara/Leather, Full Black Alcantara headlining + pillars and blind shelf, Bespoke Flat Bottomed Sports Steering Wheel, Dark Myrtle Wood, Autodim Mirrors, Bose, Blinds, Digital TV, Ski Hatch, Modified rear exhaust section for extra V8 Burble  Audi S8 D2 Final Edition 2002, Avus Silver with Red Leather Interior Tiptronic with Sport mode button, Sony rear entertainment package, Bose sound system, Audi Navigation Plus, 20 inch Final Edition alloys, Full Cat Back Stainless Milltek exhaust, giving a great V8 burble Audi A8L D2 4.2 Petrol with LPG - Ebony Black Audi A8L D4 FL 4.0T Petrol twin turbo - Havana Black Audi A2 1.6 FSi Sport - Dolphin Grey with Votex body kit and Red Leather Interior and some other A8's A8L's and Mercs
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#4
15th November 2010, 07:43 AM
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audi 's alusil engine rebuild resources part 2
Some observations about Audi’s 4.2 v8 alusil engine
From 1995, when production of Audi's alusil 4.2 v8 started, it took Kolbenschmidt (block manufacturer)and mahle(piston manufacturer) 11 years to release the (reconditioning of aluminum engine blocks) manual, first edition 2006. before this time sunnen was providing the information about exposing the silicon glass cyrstals with their diamond paste. There was some confusion from the manufacturers about using chemical etching to expose the surface in the begining. Audi has also hidden most of the 4.2 internal engine specifications, like piston to wall clearance. There is also confusion when using forged pistons of 2618 or 4032 alloy because their different expansion rates and wall clearances. 4032 alloy expands 18% less than 2618 and therefore can run tighter clearances; Wossner recommends .0020-.0025? and only makes pistons from 4032. You could run a looser clearance on them and not hurt anything. Someone using the standard audi oem spec. and boring for stock piston clearance while running a 2618 is going to stick them. No question about it. Je-Pistons makes 2618 alloy pistons which need at least .0030? clearance. Another issue is ring gap, if the spec says .008 to .016 . If they were to tight, as the ring grows, the gaps come together and you can kiss your cylinders good bye. Better to gap on the larger side and error on the side of safety. Bmw, Mercedes and Porsche also used alusil for many years and the bmw v12 with cast pistons used a very tight piston to wall clearance of .0015? or less. So many alusil engine rebuild failures are due to wrong piston to wall clearance issues and using rings that aren’t using a barrel shaped face. the wrong iron/graphite skirt coatings can also lead to scouring. Audi will not sell you oversize pistons or rings,(disposable short block) except maybe for the 4.2 rs6tt (elsawin), and Mahle who made the 4.2’s originals will charge you a fortune for custom sizes with long waiting times (even goezte stopped selling 4.2 aqh belt drive rings this year). kolbensmidt says in the reconditioning manual at 3.1.2 that "the availibility of oversize pistons is determined by their demand and sales potential" so no demand or sales potential because its "irreparable". Euroring sells abz and other 4.2 rings. At the moment Woessner-Kolben is probably the best proven alusil custom size piston maker due to, being a German manufacturer (close to the source), skirt coatings, using barrel shaped rings and only 4032 alloy. Je-Pistons, jhmotorsports and 034 also have pistons for the alusil 4.2. How many pistons have been thrown away by the alusil engined Porsche 944turbo, 911 and 928 racers like Lindsey Racing, Racersedge-inc or 944enhancement (all alusil/wossner specialists)learning about glass cylinder honing. The porsche racing crowd has the most experience in alusil engine rebuilds. Their advice is, make sure you measure the bores cold when checking them through the boring/honing process. The heat generated in the boring/honing makes the cylinders grow (can begin to simulate a up to temp engine) and they must cool down first. Otherwise your too tight on the clearance. About Darton's MID sleeves, from an expert. Sleeved engines have always had their share of failures, it is usually because the shop that did the work did not have experience in that particular block and how to sleeve it. The MID sleeves need to be installed with a very high level of accuracy, you can’t do that with a ‘standard’ machining process, it needs to be a programmed CNC operation. Its not cost effective to do this for one block. Some go successfully to nikasil plating like Ln-Engineering. Millenium Technology is a respected nikasil plater of alusil blocks and at least one 4.2 builder has used US-chrome(usnicom.com). However Capricorn is plating the 4032 alloy liner and not the alusil block itself in the Lemans Spyker. Why does audi tell its customers to change the oil every 20000 miles (longlife service), when the oil laboratories (bobistheoilguy.com) proved that fuel dilution on a 4.2fsi rs4 was 5% after 6000 miles?(the oil’s useful life finished). however they found fuel dilution on the non fsi 4.2 much lower. 20000 miles is still crazy. Alusil silicone crystal walls are very abrasive on the rings with many 4.2’s in Germany over 200000 kilometres(120000 miles) burning enough oil to be called a 2 stroke. So how to keep our beloved Quattro’s running with the disposable-glass short block. Kolbenschmidt mentions the audi 4.2 block in the reconditioning manual at 3.1.3 "irreparable aluminum engine blocks?" when it says "one renowned manufacturer advises that certain engine blocks must be replaced completely if the bearing caps of the main crankshaft bearings are opened" and then says we know competent machine shops consider it a "special challenge" to rebuild these blocks, indeed! Maybe irreparable also because of the narrow bore spacing of 5.5-7mm used in the fsi and belt drive 4.2. For comparison the porsche cayenne 4.8 block is best with at least 10mm between bores.(audi engineers were trying to make the 4.2 front to back narrow as the four wheel drive Quattro system makes it hang over the front wheels. Audi moved the engine back 5” within the chassis in 2007 with the S5’s mlb platform. This was accomplished by changing the position of the front differential and the clutch inside the gearbox/transmission). The tight bore spacing makes it difficult to put in new liners/sleeves due to thinness between cylinders. this also makes it difficult to obtain big reliable hp/torque numbers when supercharging/turbocharging the 4.2. The exception to this is rs6 4.2 tt block, (which uses the same bore spacing ,with water jacket modifications and even crank/rods/pistons interchange with the belt drive 40v 4.2, although pistons are 9.1-1cr instead of 11.1-1cr in the s8 4.2)which when modified, regularly make 700+hp in Europe. Some even have 300000 kilometres(180000 miles) on them. It’s a shame the 01e 6 speed manual doesn’t directly bolt up to the rs6’s slightly different bolt pattern on the block, though someone is selling an adapter plate with starter motor kit. From all audi's NA 4.2 v8's, the 32 valve belt drive in the early s8, the 40v beltdrive in the facelift s8, the 40v chain drive inthe s4 and the 32v fsi in the rs4, the belt drive 4.2 40 valve is the toughest block casting to build upon, confirmed by mtm, the best audi tuner. We don’t hear much about damaged rs6 4.2 blocks due to the low production numbers of 6000 compared to A8/S8 d2 4.2 -100000 in 8 years of production, but how many damaged a6/s6 4.2’s and s4 chain drive 4.2’s in the audizine forums engines failures list. Now that two of the best liner/sleeve companies are involved with the 4.2; La-Sleeve using ductile iron and Capricorn-Group using nickel-ceramic plated aluminium sleeve on the Lemans Spyker NA 4.2. I hope that rebuilding 4.2’s for increased power on a large scale will become more affordable. Currently only one rebuilder (Eurospecsport) is offering off-the-shelf 4.2 engines. Darton even sleeves an inline Audi/Volvo 5 cylinder block that kms VanKronenburg in Holland uses to make 700+ hp. Will the problem of 4.2 piston scouring fill junkyards with dead Audi’s in the next 5-10 years. Ideally (in the future maybe) custom block manufacturing companies like Dartheads and Worldcastings (where 1-2000hp V8’s originate, crazy americans) might sell new redesigned 4.2 blocks (don’t know how with that bore spacing) or crate engines even, for boosted applications. Normally they only sell Gm/Ford blocks but recently have started making custom 4 cylinder Honda blocks(strange?). Only problem with gm/ford blocks, is to support 1000hp they are 5” longer(due to bore spacing) than Audi’s 20” 4.2. The 500hp gm ls7 engine in the z06 corvette even averages 21 mpg, same as my s8’s mpg although s8 is 300kg’s heavier. Lets face it a 1700kg car needs 450ft/lbs of torque to get moving and 4.2 litres can’t make that without forced induction, example rs6tt. This insanity is leading to my conclusion and maybe the next Frankenstein development for my S8 will be the GM ls3 crate engine with the S5's manual transmission. all links for referenced companies have been added to part one Last edited by r8dream; 15th November 2010 at 08:08 AM.
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#7
15th November 2010, 12:11 PM
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No offence meant mate (takes foot out of mouth)
 I did enjoy the read it’s nice to have a (slight) understanding of the dark arts of Audi engines, I say slight because I’m not cleaver enough to understand it. If it has more than 8 valves and no carb’s I’m screw’d
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#9
24th April 2011, 08:56 PM
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Quote:
__________________
Conan (the Librarian) Watch it if you dare Currently, 2000 S8, Merlin Purple, Leather Pack 1, Winter Pack 1, SPAX adjustable suspension, AP Racing 6 pot front caliper, 385mm fully floating disks, EBC Yellow Stuff Pads, Black Diamond grooved rear disks and predetor pads, D2 Doctors Brake Block. 1997 4.2 A8SQ - the Projekt. 12 years and ongoing! 1997 4.2 A8SQ - Ming Blue. Restoration sat waiting; saved from the Scrapyard 2003 C5 Allroad 4.2Q - Cobolt Blue. Towing car. Laid up awaiting manual conversion. 2005 C5 Allroad 2.5TDi FE - Grey - Workhorse. 2015 Q3QS SLine - Daytona Grey. Lots of extras! Long Haired Admirals cutter. Previously 2003 C5 A6 1.9TDI FWD - Loaner from D2 Doctor Lifex 1997 S8 - Ming Blue. Loaned out and written off. I loved that car. My first engine swap after cambelt failure. 1996 4.2 A8SQ - Ming Blue. 178k on a cambelt! Trader's 8. Delivered to A8Parts at Lifex. 2003 2.8 A8SQ - powder blueish. Fill in for a while. Sold on. 1998 1.8T A4 Avant FWD. Ming Blue (there's a theme here), PEX for the 97 S8. And a list of non VAG going back 40 years before I saw the light.
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#10
26th April 2011, 08:44 PM
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yes mike i know they rebuild landrover engines, but they are the best lr v8 "alusil" block rebuilders and therefore have alot of experience and the best eqipment (sunnen) to hone alusil blocks. i think if you ask they would do the audi block. there are probably less then 10 machine shops with this experience in the uk. capricorn in basingstoke is still the best, as they did the spyker lemans cars.
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