Movment in dizzy

mustang68

popped the distributor cap off the other day and I was having a look at the rotor, there is some movement in the rotor shaft, maybe about 5degs, is this ok?

Anan1

From (very) vague recollection, isn't there some sort of a centrifugal advance mechanism that varies ignition timing with engine speed?

Wheelnut

In theory 5 degrees is an error and should be corrected, on the other hand 5 degrees was the amount the ignition was retarded for the so-called "conversion" to run on unleaded petrol and the effect was never noticed. Furthermore the old distributors relied on springs, spinning weights and a vacuum to adjust the timing for various conditions so when wear set in within a few years, the timing was always a million miles from the ideal. To correct you 5 degree play you might need a new distributor and camshaft because the play is probably where the drive gears meet.

The above is a long-winded way of saying that it's probably not worth trying to fix. If you set the timing by using a strobe light with the engine running it should allow for any play in the system.

Kevin_Herron

mustang68 wrote: »

popped the distributor cap off the other day and I was having a look at the rotor, there is some movement in the rotor shaft, maybe about 5degs, is this ok?

I presume you mean play in the direction of rotation?
You are turning it on the centrifugal advance.

mgbgt1978

Different car I know, but three mini's here and about the same amount of "play" on them all.

Wheelnut

If it's the centrifugal advance, resistance will be felt as it's turned because it's moving against a spring, and the rotor will return to it's original position when released. I took it from the OP that the movement was just looseness and if the rotor shaft was turned 5 degrees it would stay in the new position.

mustang68

Don't think I have a centrifugal governor, I have vacuum advance, it's not spring, just sloppy as I jiggle it back and forth.

As pointed out if it is loose I'd have to change the camshaft and the rotor shaft in order to correct it, so I think I'll grin and bear it for the moment.

Thanks for all the feedback.

Kevin_Herron

mustang68 wrote: »

Don't think I have a centrifugal governor, I have vacuum advance, it's not spring, just sloppy as I jiggle it back and forth.

As pointed out if it is loose I'd have to change the camshaft and the rotor shaft in order to correct it, so I think I'll grin and bear it for the moment.

Thanks for all the feedback.

Your Mustang has both.
To put it extremely simply, your would be using your vacuum advance from quarter to half throttle and the from half throttle onwards you would be solely using your centrifugal advance.

If the 'play' you are talking about is in the direction of rotation, its fine.