Free Play in Rotor?

[Knot Waiting]

I put a new cap and rotor on my engine tonight for no other reason than I didn't know when it was last done. What caught my attention was that I could spin the rotor pretty effortlessly left or right about 1/4" (maybe less) before it stopped. There is no slop in the shaft, just able to "rotate" the rotor a little. Is this ok? Thanks for your thoughts.

 

[Don S]

Re: Free Play in Rotor?

What are we working on? What distributor?

 

[Knot Waiting]

Re: Free Play in Rotor?

Whoops, suppose that might help eh? 1991 Mercruiser 7.4, 454 Mag. Bravo 1

 

[Don S]

Re: Free Play in Rotor?

Hmmmm. should be a Thunderbolt IV distributor, no advance weight to allow movement. Is this easy movement or do you have to twist hard to feel it? May be nothing more than slack in the gears. 1/4" really isn't that much, and it's not like the shaft will move back and forth.

 

[Knot Waiting]

Re: Free Play in Rotor?

It's pretty easy to move. However it stops firm either direction. I didn't want to twist too hard on it though. Shaft is tight and clip is in place at the base of the rotor housing.

 

[Don S]

Re: Free Play in Rotor?

You're probably fine, you are probably just feeling the backlash between the distributor gear and the cam gear. You can always pull the distributor out and make sure the gear isn't worn excessively. Also check there is no play between the roll pin and the distributor gear on the distributor. No movement should be seen there.

 

[Lyle29464]

Re: Free Play in Rotor?

Are you saying the shaft is not moving at all. That the slack is because the rotor does not fit snug? If so 1/4 inch will be a bunch on timing.

 

[Knot Waiting]

Re: Free Play in Rotor?

Pshew [wipes nervous sweat from forehed] Once again Don you have gone above and beyond for an otherwise complete stranger. Thank you very much for all the help over the years. Digital cheers! - Logan (Knot Waiting)

 

[Knot Waiting]

Re: Free Play in Rotor?

Lyle, the shaft turns left/right a little but otherwise is tight.