Embarking on a DIY car repair journey can be both challenging and rewarding. Recently, I tackled a clutch replacement on a 4.2l V8 Audi, a project filled with learning curves and satisfying progress. After removing the V8 engine and letting it rest, I finally had the chance to dive back in. My new LUK DMF023 flywheel, designed for the 30V V6, and a South Bend Stage 1 clutch were ready for installation. The first step was to remove the torque converter and flex plate, a task that proved to be more involved than initially anticipated for a first-timer like myself.
Removing the Torque Converter and Flex Plate
It took me a good day to understand the process of removing the torque converter. To begin, the starter needed to be uninstalled to provide access to the three bolts securing the torque converter to the flex plate.
These bolts were T55 Torx bolts. My existing Torx set only went up to T50, requiring a quick trip to Home Depot to acquire the necessary T55 bit. Removing the first bolt was relatively straightforward because I utilized a crank locking tool to hold the engine at Top Dead Center (TDC), which conveniently exposed one of the torque converter bolts.
The remaining two bolts posed a greater challenge. I enlisted the help of a friend who applied torque to loosen the bolt while I worked to keep the converter in position. In hindsight, a breaker bar and a 15/16th socket on the front crank bolt could have also been used to hold it steady, but lessons learned! It’s also possible that removing these bolts while the engine was still attached to the transmission might have been easier, but that’s speculation at this point.
With the torque converter out of the way, the next step was to remove the eight main bolts, a thin spacer, the flex plate, and the thick spacer. After these components were removed, the rear of the crankshaft was exposed, ready for the flywheel installation.
Flywheel and Clutch Installation: Important Bolt Considerations
An important detail to note is that both the flywheel bolts and the pressure plate bolts are stretch bolts. When installing a new flywheel, and especially a pressure plate, it is crucial to use new bolts. I sourced mine from ECS Tuning. While they are known for high-quality parts that often come with a premium, in this instance, their assembled kit of 8 flywheel bolts and 6 pressure plate bolts for the 30V V6 flywheel setup (ECS part #N90705901KT2) was competitively priced at $29.60, plus shipping.
Before removing the flex plate, I marked the location of its sync pulse, indicated by the missing two teeth on the tone wheel. This was positioned around the 2:30 mark, when facing the rear of the engine.
During the flywheel installation, I attempted to align the sync pulse in the same position. However, I discovered that the bolt pattern on the flywheel dictated a slightly different position, closer to the 4 o’clock mark. This was due to one gap between bolt holes being slightly wider than the others.
This raised some questions. Was this intentional design by Audi to prevent incorrect installation? Is the sync pulse solely for speed sensing, or does it also play a role in determining engine position, alongside the cam sensors? Does the position matter, and would I need a specific ECM file that anticipates the crank sync pulse in this new location? The flywheel could only fit in this one orientation, leaving me to wonder if this was the intended design or a manufacturing variation from LUK. If anyone has insights on this, I’m all ears!
Another point of consideration was the thin spacer removed from the front of the flex plate. Contrary to some advice suggesting it was needed behind the flywheel for clearance, I found I could hand-crank the engine without it, and it seemed like the flywheel had sufficient clearance similar to the flex plate. Since the engine rotated freely, I decided to proceed without the spacer, install the clutch, and mount the engine into the Audi A4 to mate it with the 5-speed manual transmission.
Torque specifications, as per Bentley manuals and various forums, are crucial. Flywheel bolts (x8) should be torqued to 60Nm (44ftlb) + 180 degrees for a dual mass flywheel (like mine), or + 90 degrees for a single mass flywheel. Pressure plate bolts require 22Nm (16ftlb), tightened in stages and diagonally, similar to wheel bolts. It’s important to note that some sources incorrectly list much higher torque specs for the pressure plate bolts, which can lead to snapped bolts – stick with 22Nm (16ftlb). I applied a small amount of Loctite to the pressure plate bolts for added peace of mind, although it might not be strictly necessary given how tightly they were initially installed.
Engine and Transmission Mating: Overcoming Alignment Challenges
Before installing the engine, I had to transfer dowel pins from the old transmission to the 4.2 engine. Removing these dowels proved tricky without damaging them. Using small vice grips to gently turn and pull, I managed to extract them, though a couple required some reshaping afterward. They were then tapped back into the dowel holes on the 4.2 engine.
The engine installation itself was quite a workout. Aligning the engine and transmission perfectly, both in angle and height, took numerous attempts. I probably attempted to slide the engine onto the transmission shaft 10-12 times. Each time, it would get agonizingly close, stopping about half an inch short. Despite careful alignment and even using bolts to guide it, it just wouldn’t fully seat. I suspect the transmission shaft was hitting the pilot bearing rollers inside the flywheel, indicating a slight misalignment despite my efforts. Forcing it was not an option. After 3-4 hours of struggling with a friend, we decided to call it a day.
A couple of days later, we revisited the engine mating. Prepared to remove everything and inspect for obstructions, we decided to try one more time. With my friend at the front wiggling the engine slightly side to side, and me underneath pulling on the oil pan lip and vibrating it, the engine surprisingly began to slide in! It wasn’t a seamless “plop,” but it moved without force, which was reassuring. A subsequent hand-crank test confirmed the engine rotated freely.
Next Steps and Lingering Questions
Moving forward, the engine mounts and drive-by-wire accelerator pedal are next on the list. Wiring, radiator installation, and replacing wear components like the water pump, timing belt, tensioner, valve cover gaskets, and cam chain tensioner pads are also upcoming tasks. While significant progress has been made, there’s still much to do.
The question about the flywheel spacer remains in the back of my mind. Although the engine currently rotates freely without it, the prevalence of advice suggesting its necessity causes some lingering uncertainty. Hopefully, initial engine cranking, with fuel and spark plugs disabled, will provide further reassurance that everything is correctly installed and running smoothly on this 4.2L V8 Audi project.
