Rotor Play

[Walt Ebie]

Just noticed (while correcting another problem) the rotor on my '30 coupe has what looks like about a quarter-inch of play. That is, it doesn't set tight on the cam. Tried a new rotor and it's the same. Is this a normal fit? Car seems to run okay but it made me wonder.

[1931 flamingo]

What you may feeling is the backlash in the dist dr shaft. When you move the rotor is the cam it sets into moving??
Paul in CT

[Patrick L.]

Is this side to side play or is it rotational ?
1/4" bushing play is a lot.
1/4" rotational is not.
I have a feeling the rotational play is in the shaft and not the rotor/cam. When setting the timing that play needs to be taken into account.

[29er]

Check out the 2nd and 3rd diagrams for an explanation of side-to-side vs rotational play. I think this might help explain the other comments. Hope so!

http://modelabasics.com/Ignition.htm

[Henry1953]

I had a rotor that was wobbly on the cam. It wasn't old looking and I can't remember which supplier I bought it from. I bought a replacement from Brattons and it fit very snugly. I also replaced the one piece shaft with a two piece drilled in the top for lubrication. It eliminated most of the backlash that I had.

[Walt Ebie]

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Thanks for the replies - what I have is rotational play - does not involve moving the shaft. Looks like the small 'nib' inside the rotor that fits into the slot on the cam is a good bit smaller than the slot that's made to receive it. But, as I said, it seems to run okay. Got my new rotor at Snyder's - maybe the Brattan rotor is built different inside?

[Brentwood Bob]

The distributor cam screw head may be too high.
Bob

[Walt Ebie]

Seems like a case of the cam slot being too wide for the nib on the rotor that fits into it. Or vice versa.

[Brentwood Bob]

Got any other cams to check the slot? The first time I read this I thought the cam nut was possibly sticking up to high so the rotor could not seat properly.
Bob

[Mike V. Florida]

Originally Posted by Walt Ebie

Thanks for the replies - what I have is rotational play - does not involve moving the shaft. Looks like the small 'nib' inside the rotor that fits into the slot on the cam is a good bit smaller than the slot that's made to receive it. But, as I said, it seems to run okay. Got my new rotor at Snyder's - maybe the Brattan rotor is built different inside?

Just take the "slop" in account when you time the engine and you will be fine.