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Rotor

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irish

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Recently installed a new distributor cap (top entry) and rotor on my 61' Sprite. Also did a complete "Ignition Circuit Testing" as detailed in the Sprite Manuel (Section Ba.4). All tests passed (wiring, coil primary and secondary, dist.points etc.) except the "Rotor Arm Insulation Test." This test requires you to switch on the ig., hold the coil H.T. lead 1/8 inch away from the rotor electrode, and flick the points open: if no spark occurs the rotor arm insulation is satisfactory, if a spark occurs the rotor arm must be renewed. A spark did occur on my test indicating I should renew the rotor.

I'm not sure exactly what is meant by the rotor arm insulation; is it material inside the rotor, or is it the insulation pad underneath the rotor?? Input appreciated...

I'm getting a good spark from the H.T. lead into the dist. cap by no spark from the ig. coils (spark plug coils) so the rotor is screwing something up but it doesn't seem logical that that little rotor could cause so much trouble specially being brand new...advise needed... /ubbthreads/images/graemlins/cowboy.gif
 
Stan, what you are checking is that there is no electrical continuity between the brass arm of the rotor, and the distributor itself. If there is no spark during the test, it means that the rotor itself is properly isolated from the distributor. Moisture, dirt or grease could cause a path to ground. I'd try removing the rotor, cleaning and drying everything thoroughly, and trying again.
You can also use your multimeter to check for continuity between the brass portion of the rotor and the distributor. There should be infinite resistance between the two.
Jeff
 
[ QUOTE ]
if a spark occurs the rotor arm must be renewed. A spark did occur on my test indicating I should renew the rotor.
I'm not sure exactly what is meant by the rotor arm insulation; is it material inside the rotor, or is it the insulation pad underneath the rotor?? Input appreciated...

I'm getting a good spark from the H.T. lead into the dist. cap by no spark from the ig. coils (spark plug coils) so the rotor is screwing something up but it doesn't seem logical that that little rotor could cause so much trouble specially being brand new...advise needed... /ubbthreads/images/graemlins/cowboy.gif

[/ QUOTE ]
I agree with Jeff,


The spark indicates that the rotor is defective as you say.

The rotor arm insulation is the rotor arm material between the brass strip on top & the metal shaft that the rotor arm mounts on. (The rotor arm itself)

It is not unheard of for replacement rotors to have an insulation defect. A number of "Lucas" replacement rotors have been reported to be defective. Usually the problem doesn't show up until the engine has been run too far from home to be convenient. Try your original rotor & see if it does the same thing. If the old rotor turns out to be OK, keep it & try to find another "good" one for a spare.

Both of your above statements indicate that the rotor insulation is defective.
D
 
Interesting that the next day I did the H.T. lead on the rotor and had no spark; as you suggested, probably had some moisture or dirt causing the conduction...thanks for the reply
 
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