Rotor Arm.. Round or Triangle

Post Thu Jul 31, 2014 10:55 pm

Doing the cambelt service next week. I wanted to spare my wallet and do the rotor and dizzy cap in the next month or so with genuine parts.. but I'm guessing it's stupid not to do it while the radiators already out, as I'll only have to get it all out again and drain the fluids again.

My question is what type of rotor arm do I need? I'm seeing a round one and a triangular one.. both are on real OEM for my car. One under the 'ignition wiring' diagram and the other under 'distributor'.. Can you only tell once you've removed it or what?

It's a 1990 M2OB20 engine.

Post Thu Jul 31, 2014 11:00 pm

Buy Bosch , Brehmi or Beru parts from CP4L or ECP. Wasting money on IDENTICAL parts in BMW boxes will not make you car run any better or worth any more !

Post Thu Jul 31, 2014 11:03 pm

Don't use the drawings on RealOEM as an actual guide of what the parts will look like. Just order an OEM equivalent of the bit you need using the BMW part number, and make sure the part is one of the manufacturers pete mentioned.

Chances are you'll get a triangle-shaped rotor.

Post Thu Jul 31, 2014 11:03 pm

I've read a lot of bad reviews about Beru dizzy caps. Obviously their other stuff is OEM standard but their dizzy caps have been known to fail after 5k miles. With a BMW part at £90, and Beru at under a tenner, I guess i can see that happening.

I was going to go for Bosch... seems a good compromise and mid range price-wise.

Post Thu Jul 31, 2014 11:06 pm

Grrrmachine wrote:Don't use the drawings on RealOEM as an actual guide of what the parts will look like. Just order an OEM equivalent of the bit you need using the BMW part number, and make sure the part is one of the manufacturers pete mentioned.

Chances are you'll get a triangle-shaped rotor.

Well it was actually the part numbers that are duplicated.. The round one is equivalent to 12111286111.. and the triangular one 12111734110. Both numbers are on my Real OEM part search

http://www.realoem.com/bmw/showparts.do ... g=12&fg=05

http://www.realoem.com/bmw/showparts.do ... g=12&fg=05

Post Fri Aug 01, 2014 12:43 am

There is absolutely no advantage in changing the rotor arm or distributor cap if they are in good serviceable condition.
Statistically, the most likely parts to fail on your car are those that are brand new.

Post Fri Aug 01, 2014 4:03 am

i've used Bosch and Bremi never had issues. i agree with Brian unless there is an actual ignition issue you will never notice the difference. forget about BMW

its also not hard to change the dizzy and rotor with radiator in place with the right tools to get into a few tight areas

Post Fri Aug 01, 2014 6:29 am

12111286111 is for cars with a mechanical distributor. If you entered your vehicle details correctly into RealOEM, then it shouldn't be displaying that option for you. You need 12111734110.

Post Fri Aug 01, 2014 6:44 am

Brianmoooore wrote:There is absolutely no advantage in changing the rotor arm or distributor cap if they are in good serviceable condition.
Statistically, the most likely parts to fail on your car are those that are brand new.

Well without going too much into it, I have been having issues that could be attributed to them, slight misfire at times, lumpy idle etc. I thought these were the sort of items that should be changed every other inspection 2..

Post Fri Aug 01, 2014 6:45 am

Grrrmachine wrote:12111286111 is for cars with a mechanical distributor. If you entered your vehicle details correctly into RealOEM, then it shouldn't be displaying that option for you. You need 12111734110.

Ahh not sure why it's showing me both then! I have entered my VIN on that site. Thanks though.

Post Fri Aug 01, 2014 11:35 am

doesnt the later 320i use the same basic things as the 325i?

http://www.ecstuning.com/BMW-E30-325i-M ... /Ignition/