Dizzy modification
 

So I locked my distributor. Which means I no longer needed the ugly vacuum advance diaphrams hanging off the side. I also did the TFIDFIS ignition and am only running leading plugs. So I no longer needed the J109 igniters either. Then I started removing everything I no longer needed from the dizzy. Then I milled, sanded, welded, and cut excess off the dizzy body to look somewhat decent. So.... there's the back story.

Now, the main center piece that rotates on ball bearings is usually held in place by the vacuum advance arms. After they are completely removed, how do you keep the ball bearing piece that holds the magnetic pickup from rotating freely on its own? I was either going to weld it or make a screw down clamp to hold it in place. Does it have a specific location?

Here's a pic of it now just for fun. I'll have a bunch more in my Rx2 thread once I update it.

Why are you eliminating the vacuum advance?

When I modded my dizzy instead of making the advance solid I merely tacked a stop on the slide and left to work from Idle timing to what ever the advance is set to stop at . Why do you want to remove advances ? Do you stil have the springs on the mechanical advance or did you remove them as well ?

I removed the them because I am going to turbo. So basically I locked it. The springs and everything are removed and the weights are welded at full advance.

What would happen if you locked it before any advancement...? I think that's how mine was done....?? Wouuld it throw off where the marks on the pulley are...???

It's better to lock it before any advancement. Makes it stab in easier - everything lines up.

Now Sen2two is going come in and say to do it his way because if the welds ever break, the engine won't be able to advance itself to death. Well, if you don't have faith in your welds that's one thing, but if you're staying NA, that's another thing.

I'd say do it the way that makes sense to you.

other way around.. if it is twisted to full advance and locked
.. then it will drop in at a normal stab position using the dot and mark and still be able to twist to 18- 25 degrees base timing

if you weld it locked at the non advanced position you can only get 15 degrees or so before you run out of adjust in the base

as such these you drop in deliberately out a tooth ( when engine at TDC or -5 mark )

or , more correctly , you sit the engine at 25 BTDC and drop it in with pin and dot aligned

all is good if your desired base timing on the pulley ( usually 18- 25 BTDC ) also has the dizzy pickup adjacent the vane





the alternative method used in some ( piston ) dizzies is to just pull the springs entirely

and thus at any rpm the engine goes to full mechanical timing


gerald describes a partial lock , ( or more correctly a regraph )
where he has altered the limits of the mech curve , though retains some
allowing a more aggressive base timing that suits the modded engine or fuel
and still not allowing the timing to exceed that 25 BTDC at revs
( as would have happened had he merely adjusted the base timing position )

further " regraph " mods would be in a ( piston ) dizzy to add weight or take it away from the bob masses
or to change out the springs holding them

on our rotary dizzy , usually it is a matter of poking a thin screw driver through the hole in base plate and using it to bend in ( or even out ) the posts holding the tension on the spring
one one or both springs



the OP needs a tack weld or to make a clamp into one of the screw holes that holds down the race

I made a clamp to keep it in place already. Just in case I change my mind, it's still reversible.

Does it matter where I rotate it? With the magnetic pickup unplugged, it can spin the full 360 degrees around the shaft.

1 Someone locked a dizzy the way I described, so that's why I suggested it.
2 I locked (welded) a dizzy this way and it worked as intended, so that's why I suggested it.
3 Someone did a partial lock where they added weld to the outside of the slot so the dizzy goes to 10 degrees. I use this on a blow through Nikki+S5 turbo.

wont matter where it ends up as long as when motor is at the timing you wish,, the vane is adjacent the pickup

you kept the trailing pickup BTW ( not that it matters )