Hot Rods GM HEI Reluctor

Gentlemen,
This may be a foolish question but why does the reluctor contain the same number of points as cylinders? It's similar in concept to the ignition cam lobes of a point style ignition, but the reluctor aligns with all of the points of the shaft rotor as it rotates at the same time. The external pointed magnetized ring is continous so how does the signal get fed to the coil to fire individual cylinders? Is the potential spark available to all the cylinders at the same time with the cap rotor making the selection to deliver the correct firing pattern? Thanks!

 

The rotor position is what determines which cylinder gets spark. The reluctor has the same number of points as the number of cylinders, because if it didn't, then not all the cylinders would get a spark, eh?

 

Jim,
My misunderstanding comes from my small cap GM HEI that has six points on the magnetic pick up coil ring aligning symmetrically with the six points of the reluctor. If there was one point on the pick up coil and six on the reluctor, it would be easily understandable. Do all the cylinders have a spark potential on each revolution with only one selected by the rotor? Thanks for your response and patience.

 

There is only one cylinder getting "spark potential", and that is the cylinder who's wire on the cap, the rotor is pointing to.

The reluctor aligns every time any cylinder needs to fire, which is what makes the spark potential at the coil. The rotor aligns with each cylinder's plug wire once per distributor revolution, that makes the spark potential from the coil go to that particular cylinder.

The points on the reluctor are all part of the same thing, there is only one connection to the reluctor pickup coil. It puts out a pulse every time any cylinder needs to fire.

I guess if you grew up with a computer sending information to different coil packs, this stuff which is so simple, must seem like magic? and it's hard to understand. I sympathize. I wish I could explain better.

 

Since GM uses a circular pickup coil it is necessary to have multiple points around the cir***ference to properly excite it. 8 points on both produces 8 sparks per revolution of the distributor. The rotor does the job of distributing the spark to the right cylinder at the right time.

 

Gentlemen,
I much appreciate your kind responses. I think the fog between my ears is a little clearer. Have a good holiday!
Jim