I have seen newly built engines that never had the oil galleys cleaned out. I guarantee you thats the issue. onle takes a 1/2 inch drill bit screwed in by hand to clean it out. needs to be able to go all the way into the intake side headbolt passage.
Hey mc posting for a customer, he's on his 3rd dist. the worm gear keeps sheering cam looks good timing has been set at 5°btdc engine has 5000 completely rebuilt any ideas what can cause this? I told him he has to drop his pan and get the chunks out. Says the top end is in synch with the bottom end the chain has 5k as well. He bought a transmission off me and bought two distributors in the last week.
Wow... 3 times this happened and no cause has been determined?
What does "completely rebuilt" include?
If the camshaft was bent or the oil galleys were plugged, I doubt it could have gone 5,000 miles.
I assume he pulled the rocker cover and examined the distributor cam gear? During the rebuild did he install a new camshaft? Was the head rebuilt or new? Were the cam saddle bosses line bored or spec'd?
The distributor gear is destroyed, so the cam gear would most likely be also. The cam gear bolt could be coming loose, bent, or misaligned. If the distributor hold down bolt is coming loose and the distributor is backing out of the head, the gears will misalign and crash.
By the way, I believe that is a helical gear, not a worm gear.
Gnarls.