Timing jumping with cam lope

[lukep6470]

Hi,

So I am getting about a 4 degree variation on timing at idle and low speed. I am using an MSD TFI Billet dizzy that I bought used. I think the timing jump is due to the dizzy shaft having a little bit of up and down movement. There doesn't seem to be any play in any other direction.

I suspect this is getting in resonance with my cam making the engine lope more than it needs to.

I think it might be missing a shim washer between the bottom of the dizzy body and the sleeve that holds the shaft in place. Has anyone had one of these apart?

The next question is what size is the pin used to hold the gear and sleeve in place? The standard ford pin would be a good start.

[Dwayne]

Shaun has my MSD pro dizzy in the pile of parts if you need to have a look at one.

[hybrid]

You'll always get some timing movement without a crank trigger because of the timing chain, gear etc. But yeah 4 degrees is quite a bit.