When you have a new engine and your in the break in process is it unusual for the timing to change?

I don't remember what the timing was when I first got it going but its 12 degrees advanced now.

 

If you're checking the timing with the timing wire connected on the electronic distributor, or the vacuum hose connected to a vacuum advance distributor, then the timing may very well change. If you're checking the timing properly, with the vacuum hose or wire disconnected, and its changed, the only reason it should is if the distributor clamp was loose.

Dave

 

Also, make sure the plug wires are on the correct firing order and having too tight of a valve lash can also cause timing being off.