Anybody recognize this part?

[Jack H.]

I picked up this Delco Remy rotor in a mixed bag of ignition parts at a recent swap meet. It sure looks like a D-409 at first glance, but zoom in on the area that has the yellow highlight.

There's an 18 K-ohm resistor embedded beneath that black insulation. One local NCRS member has a 'vauge' recollection of having encountered this part, but he didn't know what car/engine it was original to.

Note that the rotor has the 'short' spark tip characteristic of a 69+ 1971247 rotor versus the original 1932015 rotor from '58-69 with the 'long' spark tip. Inquiring minds want to know waz up here?

[Richard M.]

Re: Anybody recognize this part?

Interesting rotor....I never saw one with a resistor.

Rich

[Jack H.]

Re: Anybody recognize this part?

That's the concensus in the Denver community with one exception... A good ole boy here has a fuzzy recollection of having seen these but can't say where/what/when as to their original application.

In off-board query, both Joe Lucia and John Hinckley were scratchin' their heads like me. It IS a Delco Remy part (note the script DR emboss). Further the spark tip is 'short' like the D-409 rotors used on Corvette after 10/69.

The only thing that seems to make sense to me would be a 1970+ application where the engine used solid copper core plug wires AND you wanted the RF spark emission profile of conventional nylon/carbon core plug wires for something like preventing radio interference on a car equipped with a windshield embedded radio antenna.

I was hoping some other been there/done that ex-GM folks might have thoughts/memories. I know Chevy 'tweaked' certain components of the ignition system back in the 1970 model year when the radio antenna embedded in windshield glass option was launched.

By loading the rotor's spark tip with an 18 Kohm resistor, you'd be emulating the current limiting characteristics of a set of nylon/carbon cored plug wires...