this seems to be happening alot lately. when i put in the new dizzy i set the timing. everything was fine for a while. after a couple weeks it starts to run rough and after thinking it was the carb settings on the mixture screws, and acc pump. i checked the timing and it was 28 deg. so i set it back to 12. then runs great, but today (about a month later) i checked it and its at 22 deg. what would be causing the timing to off set itself? and yes i bolted down the dizzy[8D]

 

you mean it advances itself.......what dist are you using? what type of cam? how old is the eng? do you have vacuum advance? usually if theres a prob with dist gear,timing chain etc... it will retard itself, if it is advancing itself its either loose or the mech/vac advance is sticking.

 

Mech advance is sticking. My MSD did it like a ****, for varrying reasons, which I finally fixed after having to add washers to shim the weights so they didn't jack off to the side and jam open. Also check the cap, on my MSD there's a sqaure and a round post, so you can't put the cam on backwards(at least not without a hammer), and one of the posts for alignment, was interfering with the weight resetting all the way back down, so I'd set it at idle where the weight was stuck up against the post, then it would increase in rpm and the weight would break free and advance, but be unable to reset all the way back to idle timing.

 

yeah i was thinking mech advance too, ill check it out tomorrow, its already dark. i might just put different limiters in, or maybe change those little return springs.

 

if the advance turns out to not be sticking then check the roll pin on the dizzy gear and make sure it didn't shear allowing it to slowly rotate...I had a car do this once

 

i hope it hasnt come loose. when i put the new gear on and put the pin in, icut off what was stickin out with a grinder. then i smoothed it out so it looks like one piece. i think it should be on pretty good but ill check it

 

That would make my blood pressure so high, it wouldn't even be funny.