I had a chinese performance distributor that had the ring which activates the pick up coil come loose on the knurls. That caused me to reset the timing every few weeks and couldn't find the issue. Found the problem when the race car blew up a distributor so I put mine in and the car was losing a second a lap. I took a good look at it and finally noticed the problem
Chinese crap. Lol. I know my dist isn't right. I don't know if it's a Chinese one. I do know that they changed the springs, and put one of those adjustable vacuum advances. I haven't tried adjusting it but I know it's not set up right. The guys that had my car before me I can tell they tried but they didn't really know what they where doing.
I have another one I might throw in and see what it does. It's tough because its hard for me to find the time to sit there a few hrs trouble shooting. Night would be best but my neighbor had real small kids and the car is loud for me to be messing with it late. Atleast this is a 3day weekend coming so that'll help