April 1, 2016 TFRyan

Project: E46 M3 SMG to Manual Conversion Part 2

Over the past few weeks, a lot has happened since the E46 entered the shop doors; pulling the transmission, exhaust, and suspension as well as the subframe to fix a few common problems with this chassis. Plenty more is on the way, but we wanted to go ahead and throw an update your way to keep the public informed and dump all of the photos we’ve taken over the past few weeks.


Since we acquired the E46, its purpose was to be a car built with the track in mind. This meant buttoning up all of the loose ends and fixing the little issues that a car over a decade old would carry. But first, we had to focus on the transmission and all of the pertaining accessories that would be involved in the SMG to 6 speed swap.



Here, the transmission awaits the rear bracket/SMG shifter solenoid to be removed. Once it’s out, the transmission can be dropped and further teardown can commence.



For that to happen, BMW put two slide pins with snap rings over them in the joint where the SMG junk meets the transmission. One of those pins, either the one that holds the SMG components or the one that attaches to the transmission side, has to be removed to rid the transmission of all the external SMG works.



We chose the later option, and with a bit of motivation the pin was freed up and the rear shifter bracket was removed.



Also removed was the infamous SMG pump (of course, it would no longer be needed). This dreaded piece was notorious for giving out, and equally notorious for being an expensive fix. Hence why this project is occurring, to give those E46 M3 owners the option for a brighter, 6 speed filled future ahead of them when their SMG pump inevitably kicks rocks.



The intake manifold was removed out of the way to prepare for more maintenance to take place in the engine bay area, specifically the motor mounts. We’ll get to those later in the post.



Here’s a closer look at the little joint that the previously mentioned shifter bracket is connected to. It was a tight fit to remove the pins, and depending on the condition of the undercarriage of the car it could be worse for some.



And a side view of the rear of the transmission. Notice the “LIFETIME OIL. NO OIL CHANGE” sticker. Interesting.



With the transmission out of the M3, it was time to crack open the casing and get started on the refresh.



Jumping right into it, the transmission came apart with some encouragement and elbow grease from our head tech, John.



It’s always an interesting sight to see all of the gears inside of a transmission, and to see how they work in conjunction with each other.



Laid out here are all of the replacement parts that will be installed in the transmission to replace the potentially worn out springs and fittings and what-not that would/could otherwise pose a potential problem later on down the road (pun intended).



There isn’t actually a hole for what will be a standard shifter assembly to go up through and to the center console on an SMG equipped E46 M3; the SMG is all computer controlled with no shift linkages or anything mechanical in between them (news to me), so there was no need for there to be an opening for the SMG system. So we had to make one ourselves. Thankfully, it was stamped from the factory on where to cut so it was pretty straight forward.


e46 differential

More preventative maintenance; removing the diff to replace old worn out bushings that could affect how the car performs on the track. Might as well with the car being up on the lift!



Good to go! Now on to drop the subframe…



The condition of the bushings was far from acceptable, so more bushing pressing and replacing was inbound.


e46 subframe holes

Lo and behold, our assumptions were confirmed when we saw our E46 had fallen victim to the extremely common and extremely annoying subframe/shell cracking epidemic. This was common with all E46’s, and even more so with the M3s that had more power to the wheels and therefore more stress to the components on the car itself.



Another common E46 issue was the oil leakage from the CPV (Constant Pressure Valve) on the side of the block. It’s location makes it an annoying fix and most ignore it, but once again preventative maintenance is key so it goes along with the main question of this build, “Why not?”.



The once rubber O-ring had solidified into some brittle seal that split in half when the CPV was removed. RIP. A new seal was installed and the CPV returned to its respective spot.



Back to the subframe cracks, it was time to start the grind and get the surface cleaned up to better isolate the cracks for welding preparation for the reinforcement plates to be installed.



Here’s a better view of the cracks on the car. Keep in mind, this is common and happened on all four subframe mounting points.



Here’s another shot of the same crack after it was ground down and out.



An example of one of the reinforcement plates on the car.



And an overall shot of all four subframe mounting points cleaned up and awaiting the other two reinforcement plates to be welded on.



One down, three more to go!



Part of the reinforcement process had to be done on the top of the plates as well, just to maximize the effectiveness of the whole process. Part of the chassis was cut away on the area behind the rear seats for a bit more welding.



The top reinforcement complete!



More reinforcement? Why not? More chassis strengthening welding by adding spot welds along the seams on the shell. Just in case.



Protective primer applied, and awaiting a final coat of black paint to seal off the surface.



A little bit more grinding on the fresh welds to ensure the subframe will bolt up nicely, and the repair is complete.



The old bushings in the subframe have definitely seen some action in their life, and were completely trashed. Replacing them was absolutely necessary, such a small thing can affect how a car feels to the driver and how it performs.



Now that the new bushings were in the subframe, it was ready to go back on the car.



With the subframe/shell cracks repaired and painted, the subframe was reinstalled and a generous amount of internal frame coating goop was applied to prevent any rust or corrosion to take over the freshly repaired areas.



Moving back up to the engine bay, the motor mounts needed replacement badly. Dry rotted and cracked original motor mounts were replaced with brand spanking new OEM quality mounts.



While everything was removed, might as well replace the spark plugs with high quality ones from NGK!



They definitely needed replacement, who knows how long these guys have been in the car.



Comparing the fresh NGKs to the old spark plugs really shows how nasty they were.


That’s all for part 2 of the E46 update, part 3 will come along with the transmission details, header/exhaust install as well as the interior changes to suit the 6 speed set up.

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