Timing was jumping so installed new chain and sprocket gears. Improved but still jumps about 1/2 inch when timing lit. No codes. Idles 5 minutes and then a knocking appears and knocking volume increases. Vacuum test returns a steady 8 value. Driving round the block surges, stumbles, & shakes. Compression test returned all but 1 cylinder as strong so fitted new rings to complete bank. Pulled Dizzy and inspected - Spring loaded good and gear teeth good. Anyone been here before?

 

okay... what motor?

 

3.9. Your removing the vacuum line when timing right? Whats the idle speed when timing. The weights are for decelerating, vacuum for idle when timing is set, 5* +/- 1*. How did all the cylinders test when you re-ringed the motor, all good and within a few psi of each other?