25D distributer overhaul tips

OK, if you know about 25D dizzies then these questions are for you:

The cam assembly moves up and down [endfloat] separately from the driveshaft. Examining it, it seems the cam assembly shoulder rests under the head of the center screw. I checked under the head of the screw for wear, but it 'seems' ok. Does this mean the wear is in the cam assembly shoulder? Is this important, ie. what should I do?

The driveshaft itself suffers from about .018" endfloat w/ the cam assembly aside. There isn't any play in the bush laterally, ie. the bush inside is likely perfectly spherical not oval shaped. What causes driveshaft endfloat, and is .018" very bad? What should I replace? Also, I'm having quite a bit of trouble removing the pin in the drive dog so I can release the driveshaft. I put in a vise, but no luck, and I'm worried about damaging the drive dog surface. Any tips on drifting it out? Anyone know why the bushing is $25 more from VB than Moss?

I have two different types of springs inside the case. One is very thick gauge wire, probably 1mm in dia. and the other is much thinner, maybe less than .5mm. This doesn't seem right. Should I be concerned about this? Moss and VB don't carry any springs or weights. Where can I get these?

The vacc. advance looks a little rusty so before I work on polishing it up, how can I test if it works to full spec.? I know the original vacc. unit is obsolete; anyone know the difference between the original and the replacement [same on 68-70]? I heard the original is better b/c the later model was designed for lower emmissions. Any truth to that?

Thanks very much for being so patient. Sorry for so many questions, but I'd like to get everything right the first time, or at least the second. :]

Go for a new distributor. I never hassle with trying too rebuild one, its almost like trying to rebuild the shocks.

Roger wilco on Thomas's advice...

Save yourself some heartache and buy the Mallory dual point. It ain't stock but will last and works good.

Rebuilding the stock unit is expensive as you have seen and I don't think I've ever seen any specs (end float, advance springs etc) for the dist.

Years ago most garages had a dist machine (Sun/Snap-on??). You installed dist cranked it up to rpm and checked/altered advance curves etc. Haven't seen one in years. It's all done with electrons now.

For us point types the Mallory is the way to go and Mallory has already mapped out advance curves and has all parts available.

To check your vacuum advance, suck on it then put your tongue over the opening; if there is a pull, your advance unit is working.
Thomas and Don are probably correct, but it sounds like you may not need a rebuild, just another thick spring.
Used distributors are still around that work.

Yes, you guys are probably right, but I'd love to have the original dist. in there. I might bring it to a mechanic and see what he thinks. I'll try to rebuild, and if not the Mallory is the way to go. About the Mallory, which one should I get? Keep in mind I have an early B with only the PCV valve on there for emissions. I'm also planning on mod'ing the engine for some extra hp. Should I get the one w/ vacc. adavance or not? What are the advantages and disadvantages of vacc. advance? Even though I'd like to make it peppier, I still want something that's a little bit civilised. Thanks for the advice.

It dosen't sound to me that there is anything wrong with your dist. The two different size advance springs are correct. That is so the centrifical advance will progressively move with the increased RPM's. The end play you are talking about is with in specks. The main thing you worry about is the side to side movement of the shaft. You indicated that was OK. I don't see a problem with it. Even if the vacumme advance didn't work, you just advance your timing and plug of the port at the manifold and it will work fine. The only time the vaccum advance comes into play is at idel anyway. Once your RPM's are up the fly weights do the job. As for as a Mallory , the advantage is for a high reving high compression engine. I have one on my Midget and my GT. Both cars have very hot motors in them. Lots and lots of modifications. My B roaster has the stock distributor because it is bone cold stock, right down to having all the emmissions on it. I left it that way because it was a 70 model with all the emissions still working.

If Tom says they are different, go with that; I'm not where I could open one up and look in right now to see. I am surprised though and didn't remember them as being different.