[redandgearhead]

I purchased the V12 out of a 98 750. The documentation I can find shows the crank position is sensed by two Hall Effect sensors positioned 60 degrees apart on the bell housing while the flywheel spins 60 spaced tabs, except 2 tabs are missing. The 2 tabs signal the ECM's where top dead cylinder is on cylinder one. If the sensors are 60 degrees apart, then do two cylinders firing at the same time? If the second bank isn't firing at the same time, then the second sensor would be 45 degrees apart. The documentation I have doesn't talk about cylinder firing except to list the order.

Thanks for any help.

 

[Autoputzer]

Twelve cylinders, four strokes... that'd make three cylinders firing at one time. With a six-cylinder, sometimes only one cylinder is firing, sometimes two. That's what gives a six-cylinder a "bark" instead of a drone you get from a four, eight, or twelve cylinder engine.

 

[Doug Huffman]

Doesn't look like it ...

https://www.newtis.info/tisv2/a/en/e38-750i-lim/

 

[redandgearhead]

Every six cylinder engine I have seen with a distributor and a cap and rotor, the rotor only points at one spark plug at a time, therefore only one cylinder fires at a time. Three cylinders fire every rotation, but only one fires at a time. The Chrysler V10 fires two cylinders at the same instant. With a cap and rotor on each bank of the BMW V12, then it is possible two cylinders can fire at the same instant in time. I thought someone might know.

 

[redandgearhead]

I think I just figured this out the BMW V12 firing order is 1-7-5-11-3-9-6-12-2-8-4-10. Cylinders 1 and 7 share the same crank throw so they cannot both be at top dead center, so they cannot fire at the same time.

Derf.

Thanks for helping me think it through. Putting myself out here made the spark happen.