What are the advantages and disadvantages between them? It it easier to tune one or the other? What about power and reliability? And why does JWT use a dist. for the rwd dets, and do they use it for the fwd? TIA

Distributor good: old tech; lots of knowlege; millions made; economy of scale; few failure points.

Distributor bad: moving parts to wear; trigger uses high voltage and experiences metal transfer, subject to valve train stresses.

Distributorless good: no moving parts; no variation of timing due to moving parts; little maintenance; trigger is purely inductive & should last life of engine; isolated from valve train stress.

Distributorless bad: cost to build (a coil for each cylinder); cost to replace; increased number of failure points; more underhood wires.

I'm sure others can offer advantages/disadvantages that I missed.

Distributor setups can be inductive pickup too - in fact it is commonly inductive pickup triggered - I think only Nissan uses an optical interruptor disk in some of their stuff.


Another advantage of a distributorless ignition is you get a hotter spark at higher RPMs. There's more time for the primary current to build in the coil since it doesn't have to fire N/2 times per rev like a single coil setup. (where N=# of cyl).

FWIW, there are setups where the timing is obtained from the crank itself - supposed to give better timing accuracy. Also keeps people from adjusting their timing. (the PT Cruiser uses notches on the crank portion IN THE OIL PAN! to trigger the ECU). The only way to adjust timing is to reflash the ECU.