Ignition Coil: BMW, Bosch or Beru?

Post here for mechanical and engine topics such as fuel issues, transmission problems, rough idle, exhaust, electrical issues, etc

Moderators: GRNSHRK, ron, bfons

Post Reply
User avatar
Boggie
Posts: 185
Joined: Wed Jan 31, 2018 3:57 pm
Location: Buckinghamshire UK

Ignition Coil: BMW, Bosch or Beru?

Post by Boggie »

Hi All,

As part of my engine recommissioning / preventative maintenance work, I am about to order an ignition coil. Looking at REAL OEM to get the part number (12131286087), I noticed how expensive they are, and from experience the UK prices are often higher than those quoted on RealOEM ($114.46 is likely to mean ≈£140 in a UK dealership).

This seems a lot for a coil, so I have been poking around looking for a premium aftermarket coil to replace the anonymous and rather aged item currently bolted to the RH inner wing. Looking on AUTODOC, there are 2 listed as 'in-stock' (albeit in stock in another country knowing AutoDoc) but as I am in no rush as the current coil is fine and as I have some remaining credit to spend with AutoDoc I can order the coil from them and wait. They list the following equivalent coils for my car:

Bosch 0 221 118 335
Beru 11816

So, my questions are:
  • IF I were to buy a 'BMW' coil today, who really makes it? I doubt BMW but is it by chance one of the above coils?
  • Who made the original coils that were supplied on new M6/M635CSI E24 cars? Both Bosch and Beru are German companies who supplied original parts to the motor industry in the 1980's.
  • Do any of you have good (or bad) experiences with either coils on the E24?
Thanks,
Ian
1985 M635CSI
Classic Car and Bike Collector & Restorer.
User avatar
Brucey
6 Series Guru
6 Series Guru
Posts: 10077
Joined: Fri Apr 09, 2004 7:17 am
Location: Cambridge, UK

Re: Ignition Coil: BMW, Bosch or Beru?

Post by Brucey »

when any given model is new, manufacturers like to 'dual source' parts (or at least have the option of doing so) where possilble in order that they can be price competitive, have flexibility of source and not held to ransom by a single manufacturer. Thus E24 were fitted with Bosch coils (exclusively, I think) but it is almost certain that BMW had the option of obtaining coils from another manufacturer with which they worked, eg Beru. The Beru coil would be made to meet the same specification, and might be offered as an aftermarket part even if BMW did not use it as OEM or (initially) an official spare part.

AFAICT Beru made OEM parts for BMW such as ignition leads for E24, and coils for other models. If they offer an E24 coil and that coil design was approved for OEM use (even if it was never used as such) I'd expect it to perform similarly.

There may be some merit in a completely different coil if you are going racing (with a higher rev limit etc) but the OEM coil works well enough, is reliable and (obviously ) matches the Bosch ECU coil output stage.

FWIW these coils seem to be very reliable, and instances of actual coil failure are very rare indeed. I wouldn't bother changing it unless it was proven faulty. In my own (somewhat haphazard) dealings with the HT system, the rotor arm can fail (mechanically), the rotor arm and/or distributor cap can track (e.g. if contaminated), some distributor caps crack (old age) and if the plug gap gets too big (which stresses the entire HT system) the HT can even punch through the insulator nose in the spark plug before any harm befalls the rest of the HT system.

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
User avatar
Boggie
Posts: 185
Joined: Wed Jan 31, 2018 3:57 pm
Location: Buckinghamshire UK

Re: Ignition Coil: BMW, Bosch or Beru?

Post by Boggie »

Thanks Brucey,

The coil is unbranded and looking rather tired. To be fair it works perfectly well so the main initial reason for replacing it is aesthetics. However, being of indeterminate age and origin makes me a little wary so fitting a shiny new Bosch coil seems the way to go. :)

New plugs, rotor, LT connectors are sorted. Not sure if I am going to replace the dizzy cap and HT leads; they seem to be in great condition and genuine replacements will cost hundreds.
1985 M635CSI
Classic Car and Bike Collector & Restorer.
User avatar
Brucey
6 Series Guru
6 Series Guru
Posts: 10077
Joined: Fri Apr 09, 2004 7:17 am
Location: Cambridge, UK

Re: Ignition Coil: BMW, Bosch or Beru?

Post by Brucey »

bosch coils normally have a label on the side. This label may not be visible when the coil is mounted, or may have fallen off. IIRC there may be markings moulded into the insulator nose that tell you the manufacturer.

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
User avatar
Boggie
Posts: 185
Joined: Wed Jan 31, 2018 3:57 pm
Location: Buckinghamshire UK

Re: Ignition Coil: BMW, Bosch or Beru?

Post by Boggie »

Don't think it is a Bosch as it is the wrong colours but the can is pretty corroded too so will replace it with new and stick the old one in my ever growing old but ok spares bin. :)
Thanks.
1985 M635CSI
Classic Car and Bike Collector & Restorer.
Post Reply