Maybe the outer ring of your harmonic balancer has "Slipped" thus throwing off the Calibration of the Balancer to "Actual TDC" [Top Dead Center](When # 1 piston is at its highest point). The Balancer has a rubber ring in-between the inner part and outer part. Sometimes the outer part will move, from its "Zeroed" location, many times because the rubber deteriorated
The 1st time I ever encountered it, my friend told me to drag my timing mark around to "0" (sorta did this with the balancer mostly removed from the crankshaft)
We removed the old one, Then WITHOUT MOVING A THING, we barely stuck another Re-manufactured one on. When the key-way is lined up, the REMAN was not on "0".I did not fully install it, till I was convinced that was the problem. Kinda EZer to take a Part back to the store if it is not showing signs of being installed!
Are you Timing Correctly? Normally you remove and Cap off the vacuum advance line (the distributor vac hose) while you time a vehicle, also insure your IDLE RPMs are close to specs when you time it. Just remember to put it back on, when you finish!
I have seen distributors "STICK" while they are advanced. This too will throw timing off.
If your rig has "Jumped Timing" (timing chain, jumping a cog), 10 degrees probably would not make it run/ run smoother. It would more than likely, not run worth a crap, much at all!
I do not know a lot of specifics on your rig. Just trying to help the best I can. Hopefully it was something simple, like the vacuum line, not being removed during your timing procedure.
I hope this helped you
Merry Christmas to you!
Respond with NO "Bah-Humbugs"
Thursday, December 2nd, 2010 AT 2:07 PM