M42 to S54 COP

[BadCab]

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.

[DesktopDave]

I like the way this is heading...cheaper & better all around.

Once you get that right, have a shop write up a CNC routine & sell updated covers...

[BadCab]

Had to pause because i had to many pics then had to wait for the thread to get approval.

here is the rest.

Boot fits but it is too tight to get the coil in even with some organic lub.




I opened up the hole more but this time just at the top so i keep the gasket ledge intact. A little messy but it's just a test.


Boot fits and with a little organic lub and the coil slid in like a glove.


Put the car back together and decided to try get a bmw cover to fit the valve cover. I made this template for the brackets. I am going to make it smaller and cleaner.


and lower...... it probably sits too high but again, just want to see if it will work. I'll lower it when i make the brackets out of .090 aluminum sheet.









Sits high here. I hope to lower it a bit once i know exactly how high it needs to be to clear the coils. Should look OK once the brackets are painted black. I will grind up my painted valve cover once all the parts arrive to finish this.


So i have ordered 3 more coils (Bosch 0 221 504 464 OR BMW 12 13 1 712 219 ) and i also ordered an E46 03-05 coil harness for a M54 with the triangular plugs to run to the location of the original coil packs. I plan on cutting the sockets off of my old coils and hard wiring them to the M54 harness to go to the factory M42 coil plugs. I don't want to cut anything on my cars harness.

Hope this helps someone out who has been wondering about the feasability of this project too.

[bwawuz02]

The only problem I see, besides the coil not fitting, is that the connector is different. The simple beauty of the current COP kits is that they are plug and play, the stock wiring harness plugs right into the coils. I've also seen a pic of somebody who stuck the cover back on one of the current COP conversions and it sat exactly the same height as what you have pictured here.

I applaud your attempt at trying something different though, best of luck to you!

[DesktopDave]

Damn spam filter.  Approved!  Please post more!

[BadCab]

I cut up my old coils and scavenged these plugs from them. The first one i cut a bit close and did not leave a ledge. I will probably get another old coil and make another. I plan on using small heat shrink on the pins and then slide a big piece of the heatshrink over the whole thing. I have some big heatshrink that is lined with hot glue and it will seal it up. If for some reason they don't work i'll splice the E46 harness in right behind the rear relay cover.

I received my other 3 coils so i am just waiting for the E46 harness to come now. Supposed to show up saturday, if so then i will install this sunday.

[BadCab]

Well, had a stroke of luck and Fedex delivered my E46 harness a day early and the aluminum sheet came in too. I got home early enough to get the valve cover off and wash it so i am going to start cutting. Hopefully i will have a pencil COP powered M42 tommorow.

[BadCab]

There is no performance advantage to this over other COP's that i can think of but for those of us who have not gone the other COP route this is another option and for the same price i have 4 new bosch coils. At $120 a set i may swap the coils out biannually.

Wanting to get a jump on things i got most of it done this evening.

I went ahead and butchered up the harness.


..and opened up the cover.








Looks like this boot may work here.


chop, chop.


I really like how this is going together. I'll seal this boot in place with some 3M window weld.


and the reason for going this way. Tommorow i need to wash, rewash, and rewash this cover and wire these up. Once i have that done i will know how high to make my bracket to hold the plastic cover in place.

[BadCab]

Coils are in.


cover on


Plugged up


Just match up your numbers on the plugs.




HEATSHRINK, HEATSHRINK, HEATSHRINK. I went ahead and put number tags on the harness wires. I did the cars harness wires too. I figure i'll be glad i did at some time in the future.


I am only hooking up the power and signal wires on the plug. The grounds will all be tied together at the coils and an 8 gauge wire is going to the negative terminal bracket right next to the battery so there are no ground issues. Oh and more heatshrink.


Here is the harness done. Instead of using a heatgun on the heatshrink i filled them up with hot glue. They are nice and sealed this way, the heatshrink did contract a little and squeeze out some excess. I just held it sideways and let it drip out. I then ran a bead of hotglue around the perimeter too just for good measure.


All wired up.


The cover does not sit all that high up. I am pretty happy with it. I will make the brackets next. My feet and a$$ are cold so it is going to wait a few days. Car started right up, no CEL dash lights, no hiccups, went for a quick drive, definetly a little better throttle response compared to old wires and S52 coils but i expect probably the same as if i had replaced the wires with new ones. The old ones are pushing 230K.




All in all it was fun and the car seems to running real good. Hopefully i will get a little better gas mileage too. For a cleaner look the harness could go straight to the relay cover and it would eliminate all the wires but i refuse to cut this harness.

[BadCab]

I said i wasn't going to do anymore but i want this done.

I cut the brackets out of .064 aluminum sheet i got at the hobby shop. The .090 was too thick.


Here they are rough.


A little file work


After a bunch of cutting, drilling, grinding, a test fit.






Here are the brackets, i gave them a sanding for paint.


3 coats flat black


I'll have one more update tommorow of it installed and done.

[BadCab]

Last update since this project is done. Here is what it looks like.

[romkasponka]

Nice!

p.s. It could be that performance can be better a little because these new coils could have more energy to release.

[cristimm]

Great.