318 will not keep timing.

[TRIPLE-GREEN]

   Ok, I have been fighting with my 318 for over a month and it seems to now be coming to a head. I cannot get the timing to stay set.
    I have replaced the cap, wires, dist. hold down, rotor, and plugs. I go in to set the timing by removing the vacuum advance and loosen up the hold down and check with a timing light. Commonly my engine is so advanced that it is running ruff and has a miss in the idle tone. (The miss has been common at low and high speeds but commonly is just sound more then power loss) I bring the idle back down and set the timing at about 5-8 advanced and tighten things up. 
    Today I was checking it (It has been going out of time every 2-300 miles.) Lately it has been every 20 or so.
   I tightened everything down and gave the engine a little gas. I let it come back down to idle and checked it again. The bar was gone for a 10+ count. The timing has advanced again. From what I can see the dist does not move and is very secure. After a minute or two the bar came back, but then kind of danced around, never really coming back to where I had it, then shot off the grid again. I was not sure what I was missing so I just hooked the vacuum up and tried to drive it home about 2 miles. It was missing pretty badly at take off speeds. I have about had it. I am going back out now to check the timing again.
  Any questions please ask. I am about to just junk this thing and go get a new ready to run Mallory or MSD . But if I can fix the old stuff I would rather save the money. PLEASE HELP.
This is a stock electric dist. If that helps.

PLEASE HELP ME!! This car is my daily driver and I can not miss work!!!
THANKS!!

[Moparal]

I wonder if your advance weights are sticking or if there is a problem with the advance plate and springs. The arm for the vac adv can sometimes cause the plate to stick to

[TRIPLE-GREEN]

How would I fix?

[Moparal]

Look under the cap for a visual for starts, then check the rotor tower, take and manually (suck) on the vaccum line going to the advance and see if it is moving right and going back all the way, see if anything is binding. You may even have a bad spring, a bad dist drive, a worn bronze bushing or things of the sort. The reluctor, if thats the word may be loose as well

[TRIPLE-GREEN]

I will go out and check now!!

[TRIPLE-GREEN]

I went out and I think my vacuume advance is tost. I suck on the line without restriction and nothing in the dist moves. Sound about right? The plates seem to pock back when I move them by hand so might that be the issue?

[Moparal]

That can be part of your problem for sure. Also, the banlancer isnt slipping on the rubber is it? Just curious.

[TRIPLE-GREEN]

I am not fallowing. This is the first time I have really cracked into the dist. So I am still learning.

[67vertman]

That can be part of your problem for sure. Also, the banlancer isnt slipping on the rubber is it? Just curious.

What Alan is saying is you may need to check your "Harmonic Balancer" on the front of the motor that hooks to the front of the crank, where your timing marks are.  They have a rubber spacer, similar to a motor mount and they can break and cause the timing mark to jump around.   

[Chryco Psycho]

if the weights are sticking or the springs are broken under the pick up plate that is the problem , you might be better off to just grab a dist from the wreckers from a truck