B58/S58 coil pack retrofit
Your original coil packs are tired. They've been sparking for years and have degraded from the heat. Replacement bolt-in coil packs cost almost double the price of B58/S58 coil packs and pencil coils only cost ~$10 less. For the price of these and the simplicity of the conversion, it's a no-brainer to make the upgrade. Unlike R8 coils, these don't require any modifications to the DME or external drivers as these are "dumb" coils. Additionally, they have the highest spark energy output compared to the rest. More information can be found at:
Coil pack comparison
B58/S58 coil packs, Eldor brand - 12138643360
M54 bolt-in coil pack valve cover - Found on E46 models made before 09/02. 11121432928
M6 x 1.0 rivnut - I used zinc plated steel rivnuts. They came with my rivnut installation tool.
Rivnut installation tool - I used this one from eBay. It worked great without any issues. An expensive tool isn't needed for this as it's just 6 rivnuts in an accessible location.
23/64" drill bit
Straight sheet metal - I used "8 in. Galvanized Mending Plate" from Home Depot. The pre-drilled holes were the perfect size for the stock coil pack bolts.
E8 socket
Coil pack harness - You can use either the bolt-in coil or pencil coil harness, it doesn't matter.
B58/S58 coil pack connector - There are two ways to go about this: If you are good at making connectors, you can buy the connector (6x 1-1670917-1) and terminal (18x 7-1452671-3) or you can buy a pigtail harness. The pigtail can be found on many VW/Audi cars in the engine bay or PDC connectors. To make it easy, you can search for this part number 4F0973703. I had a difficult time getting the terminal to fully seat; the wire would bend/get damaged.
The B58/S58 coil packs are the same length as the stock bolt-in coil
packs. The only modifications we need to do to the valve cover are drill
some holes for the new coil packs to bolt in to and make brackets for
cylinders 1 and 3 as there is a void where the bolt were to go in to.
The method I chose to use to drill the holes was place the coil pack in and move "tighten" the bolt into the valve cover to leave a mark on the metal plate. I used that as the center point and just drilled straight down.
After drilling your hole, insert a rivnut into the hole and make sure it sits good. Place the coil pack into the valve cover and make sure it lines up good with the bolt. When you are satisfied, thread the rivnut onto your installation tool then insert it into your hole and crimp it in place. Test fit once finished to ensure the angle is good. Try your best to avoid cross-threading the rivnut as you will then have to drill it out and redo the process. If you do end up cross-threading it, it means it was at too much of an angle. Repeat the process until you only have cylinder 1 and 3 left to do.
To make the brackets for cylinders 1 and 3, I cut the sheet metal right above the next bolt hole and then trimmed it from there. The hole for the rivnut can be parallel to the pre-drilled hole. You want to bolt in your cut up sheet metal to the stock coil pack bolting location on the bottom right side (facing further away from the oil fill cap). Once that is done, insert the B58/S58 coil pack and mark the proper height for where you need to drill your hole. Once that's done, the process is the same as all the other cylinders; insert rivnut, crimp, tighten by hand and make sure to avoid cross-threading. Something really important to keep in mind: tighten the coil pack a couple threads into the rivnut before you go to install the bracket to the valve cover. That helps prevent cross-threading. You will notice the brackets aren't perfectly straight on the side; that was done to give clearance for the coil pack. I didn't want to go to the store to buy new bolts so I just cut 2 of the stock bolt-in coil bolts. There is a tiny bit of plastic protruding that interferes with where the bracket sits so you can file it down or just break it off with some pliers. Alternatively, you can shape your bracket around it.
As new BMW engines don't have their spark plug wells perfectly straight, the B58/S58 coil packs are designed with flexibility. Knowing that, the coil packs do not have to be perfectly straight when mounting them to the valve cover. When you go to install the coil packs on the car, the flexibility of the boots will handle that.
Conclusion:
There is nothing special for the installation. It's just like removing and replacing stock coil packs.
The wiring for these is pretty straightforward. If you choose to go with the pigtails, you do not need to extend the wires. If you decide to pin your own connectors, you will most likely have to extend the wiring if using the bolt-in coil pack harness but the pencil coil harness has longer wires.
B58/S58 coil pack harness
1 - Red/green(stripe) = power
2 - Brown = ground
3 - White/color(stripe) = trigger
E46 coil pack harness
1 - Red/white(stripe) = power (15)
2 - Brown = ground (4a)
3 - Black/color(stripe) = trigger (1)
Looking at coil head on, from left to right
1- Power
2 - Ground
3 - Trigger
Keep in mind, the colors for the B58/S58 coil pack harness is just to reference the first image attached below. The pigtails wires will have different colors.
Here are the pigtails I got from the junkyard
To make it easier on yourself, pull the boot out of its slot then slide it back as far as it'll go on the coil pack harness wires. Don't forget to slide on heat shrink before soldering.
The first image is dwell times from a B58 binary. I opted to set my dwell times from values between 80C and 110C.
Credits go to Stefanos Chatzopoulos for being the first to do it. I had the idea a few months before but didn't execute it until after him.