I posted this at Bimmerforums but thought you guys might be interested. The whole thread is posted there. Waiting for the rest of the post to be approved by the mods here so half of it is missing.
I have been having engine missing issues with my 92 M42 when coming off idle or mashing the pedal down at low RPMs. Car has around 230k miles but i did a headgasket and changed all the timing chain and gears 2 years ago and have had 0 problems with it. Car is throwing no codes and it seems to do it more as it warms up but not all the time. I first checked the coils and wires at night and they were arcing to their iron cores and the wires had a bit of arcing too. I tried some S52 coils i had around and picked up a little throttle response but once it warmed up it started again. Tried another set of wires but it still does it. Not sure the cables i put in are good either. They were used. Swapped cam sensors and it still does it. The coils i tried were used and of unknown conditon so it brings me to this project. Stock M42 S50 S52 coils cost $65 each and up and wires are $300ish. Even if i go to a regular COP kit i am stuck with these expensive coils. All the newer engines have the pencil plugs and at $30each you can't go wrong. A set of 6 bavautos hipo coils is $250ish and is still cheaper. So yesterday i decided to do a little proof of concept experimenting.
I have always loved the idea of COP but hated the idea of loosing my clean looking engine bay. I want my BMW cover.

Here are the S52 coils rigged up to test.

Here is a comparison of the later style coil next to the M42 wire end to show the height difference.

Coil no fit, project dead......NOT!!

Looks like the hole in my head is bigger that the cover......

Took the valve cover off and coil has plenty of room.

Grabbed a bad valve cover i had that has broken vent cover bolts to grind on.

Coil boot will not fit but it shouldn't need to go this deep anyways, just checking.

Got the dremel out with a cutting wheel and cut most of the lip off. Left a little just incase.

Chop, chop

Using my porting bit i proceded to open it up.

Ground it just enough for the coil, right side one done.

Coil fits but boot doesn't

This is how high the cover will sit.....sort of.


Decided to butcher a wire boot to make a way to seal the coil.


I guess i could make it work but i am not happy with it. The coil just rattles around.

I opened up the hole more

Went a little too much at the 1 o'clock area but that is the purpose of doing it on this bad cover. Learn learn learn.