We have a military 230 Tornado belonging to a local Fire Co in our shop that we had pulled out and repaired some oil leaks. Had the block deck and head surface machined. Installed new main and rod bearings. Installed a new crank drive gear for the oil pump. After the engine was installed it ran great and had no leaks. Two weeks later the truck was on the way to a fire call probably not warmed up at the time when it quit and would not start. It must have backfired because the valve cover gasket had blown out on one side. I found the ignition timing was off quite a bit but the timing chain timing was still ok. After turning the distributor it ran fine. It had to be turned to a position that I know it was not in initialy. For the life of me I can not determine how the timing would have changed. I did replace the oil pump drive gear on the crank during the repair, but not the oil pump. I removed the oil pump, distributor, balancer and related parts to inspect. Found the new crank gear is wearing already badly. The wear matched the wear on the old one. The wear is not centered in the middle of the gear. When you look through the oil pump drive hole in the timing cover you can see that the crank drive gear is not centered in the hole perfectly as it is somewhat forward of center. I'm thinking of machining the spacer portion on a new gear to allow the gear to set further inward on the crank and adding a spacer on the front of the gear to make up for the machining so the balancer is in it's original position and install a new pump. Has anyone had this problem? I thought the timing cover mates with dowel pins on the block so I dont believe the cover is off causing excessive clearance between the crank gear and the oil pump drive gear. I'm at a loss, I appreciate any advice. I would like to think the timing jump was a fluke but I do need to figure how to keep the gears from wearing again as new parts are hard to find. Thanks