How to lock a distributor
 

Hey guys.

I have my distributor stripped down and would like to know what you guys weld the weights to. Once the springs are removed where to you tack or weld the weights to.........

Tack the weight "fully advanced"!! That way if the weld was to ever let go it will not accidentally advance any further.

There's no need to weld anything, just remove the springs and as soon as it starts spinning it'll be at full advance. If you wanted to you could even try really weak springs for easier starting and better idle. Just make sure it goes fully advanced by 2-3k

Where to buy these "really weak springs" you speak of??? Ful advance by 2-2.5 would be pretty sweet.

Any hardware store with springs, it'll be trial and error for what RPM you get full advance at. On my dizzy I just took off the springs, never tried the weak springs, just thought they'd be a good idea. You might even be able to just stretch out the stock springs.

so lockin the distributor is a good idea? if so do you have to run the car at 2,500 rpm's and no higher? sorry for sounding so noob , but i am and really am interseted in the topic

I've always wondered that too. I thought it was so you could eliminate more vacuum lines and the pods on the distributor.
I've more been curious on how to do it.

and no - what they mean is the dizzy advances fully when the car hits 2500RPM, so any RPM above that it's all the way advanced like it should be.

the distributor, like almost every distributor, has 2 advance mechanisms in it; it has a vacuum advance and a mechanical advance.

the mechanical advance, which is the one we are talking about, advances timing as rpm increases. the actual curves are in the FSM's.

the vacuum advance uses engine vacuum to advance the timing, again the curves are in the FSM.

so why have 2 different ones? you say.

engines generally want more timing with higher rpm, which the mechanical advance takes care of, engines also want more advance at low load, IE freeway driving, which is what the vacuum advance does. just to throw some numbers out, idle timing is @0 or TDC on a 12A, and the advance we want as full throttle is around 22BTDC. the mechanical advance does this, but cruising down the freeway, the engine wants more like 30BTDC. the mechanical advance cannot do this without running 30 all the time, so they put the vacuum advance on it, and we get fairly optimal timing

ok so what is this locking out thing then?

on a turbo/supercharged engine, the 22 degrees the mechanical advance gives is too much*, so we disable the mechanical advance and run something like 10btdc all the time. the vacuum advance will still work like stock, if its hooked up.

*too much depends on the engine, the better the engine breathes the less timing you need

I dont want to hijack this thread, but would my lack of vacuum advance explain an almost imperceptable miss that occurs only at cruise speeds (50 to 70 mph) in 5th? (This happens only at very modest throttle angles)

I guess I will experiment by adding advance a little at a time while avoiding wot (in order to avoid detonation) to see what happens while at cruise speeds.....

Food for thought,... Thanks for the info j9fd3s............