Hi guys, this might be a long post. I have a buick 3.8 in my vega, block casting shows it to be 79-83, wiend single plane intake, edelbrock 500 cfm carb and hei distributor. After putting all new gaskets and new distributor ( previous owner has an oddfire distributor in it). Turned it to tdc on #1 cylinder, lined everything up and installed the distributor. I was suprized when it fired up no problem. With the vacuum advance plugged, I set the timing to 12 degrees btdc at 700 rpms. I only have a simple timing light without the dial on the back. I was all happy, let it run for a few minutes, checking for leaks, no milky oil. The head gaskets worried me the most. Then I started revving it up to about 1200rpms watching the timing go to about 20 degrees btdc. When i revved it up slowly to about 1500rpms it starts shaking til about 2000 rpms, after that it seems to get smoother. I tried advancing and retarding the timing but it still shakes in that rpm range. I did change the flexplate but you would think if it was the flexplate it would shake at all rpms. So I started to try to eliminate thing, I unbolted the converter and push the trans back but it still shake, a little less but it is still there. Then I took the belt off, still shakes. Unbolted the balancer, some of the rubber was cracked but not much, it does look like it wobbles a little at low rpms. I started the engine without the balancer on it , still shakes but not as bad. Next step might be to put the old flexplate on and try it but i can't just push the tranny back far enough to get at the the bolts.
Has anyone ever run into this problem before? I have read that these engines are externally balanced, I was going to buy another rebuild balancer but that just might make it worst.
Wow that was long!!! I have a to get a beer now. Any help or comments would be appreciated! After reading this i might have to buy you guys a drink!