1998 Detroit Diesel Series 60 12.7L DDEC IV rocker shaft issue.

So I bought a 1999 Freightliner Classic XL with this series 60 in it. Supposed to have had a fresh overhaul. Unfortunately just as the mechanic was finishing he had a bad stroke. So getting any information from him is now impossible. When I got the truck the only thing that wasn't done was the valve cover was off and fuel system wasn't attached to the head. Jakes were all on etc. I barred the engine over and everything seemed to be ok. Started it up and it ran great. Drove it about 1000 mi then an issue developed where the jake was very week and there was next to no power. Got it home and pulled the valve cover to discover that the front rocker shaft had broken between cyl 2 and cyl 3 and that the bolt at the rear end of the forward shaft, on the one cap that's got the 2 bolts in it, had snapped. The ceramic injector roller had disintegrated and put major cracks in the surface of the cam so its trashed. Also, the injector follower retainer had snapped on cyl 3. #3 rocker assembly was pretty much trashed. Pulled the rocker assembly out and checked the valves with a straight edge and there was no difference or play in any of the valves. Went to my buddies wrecking yard where he's got a large bin with good used series 60 goodies. Found the same cam, and new style setscrews on the 3166 rocker assemblies, these have the "Elephant foot" or what I'd call pillowball style and my original setscrews had button cap with the small retainer. So yay, upgrade. Anyhow, my theory, after checking the book "Series 60 – Section 1.28 Camshaft and Camshaft Bearing" In the first image you can see rocker shaft spacer and its not mentioned anywhere in the book. So after being a youturd seeing how everybody had these rocker spacers on theirs, I came to the conclusion, since mine didn't have any spacers, that the mechanic forgot them. This lead me to believe that when he tightened down the rocker shaft, that that 1 bolt had bottomed out. That he then, assuming it was tight, torqued it down either breaking the bolt or putting a hairline crack in it. This is what I assumed caused the shaft to lift, the cam repeatedly hitting that rocker assembly and the vertical forces snapping the rockershaft. So I found the rocker shaft spacers and the retainer follower at McBee and they arrived today. Since the book only shows 1 drawing and no youturd videos with them being taken off, I assumed they were flat on the underside to match the flat bolt space on the tops of the rockershaft. Which to my surprise...are not, they're curved to match the radius of the rocker shaft as if the rockershaft did not have a flat spot around each mounting bolt hole. So, with the shaft spacer on the bolt, and the bolt put through the rockershaft, there's a ###### gap! My rockershafts have a flat spot at every bolt hole, on all 4 shafts I have. What am I missing here?? Does my rockershaft not require the spacers? I already had to drill out the broken bolt I don't want to do another if it's not seating right or are the bolts I'm using just too long? Any ideas would help, Thanks

 

Different length bolts would make sense. You're right it had the old style, Wrecking yard had both. When the catastrophic failure happened, both the intake and the injector setscrew retainers blew all over. So after realizing the half assembly I got from the yard had the style that's in your pic I searched around and found the type in your pic is apparently a new(er) style, so I switched them all over to that.