Need help with small cam timing

So it seems that the tag on these engines are on timing cover only, not also stamped into block like many other series. Also found out just because the block is a 290 it could be set up for 300,350,400hp so it’s critical I have this CPL for INITIAL INJECTOR TIMING. Not part of the overhead. I also learned there is an entire novel of Cpl numbers for these, for a nt855 290 there are more pages than I could count so I was forced to backtrack. I needed my injector numbers, fuel pump numbers, turbo numbers and cam numbers. And as it turns out I have a 0187 CPL with an INITIAL INJECTOR TIMING CODE of AS. Which I understand to be .036” NORMAL injector pushrod reading at .2032 BTDC. From there since I don’t have top stop injectors I’m looking for a .170” injector travel setting. Im pretty confident on everything going forward but here’s the thing- all this info was in my manual for the 1975 truck, I’m working on a 1973. The section of the manual which shows what I thought to be a mock label with a erroneous ESN and CPL actually is what is in both trucks- Now of course the serial numbers can’t be the same, well these are military trucks so possibly? Or maybe the ESN in the book is just random, when looked up in a Cummins manual it showed to be a V configuration engine…… well I figured when I was told that everything on that data label page would be just random or an example. In this same manual is also a parts manual and every single part I take out matches those part numbers in the book, to include the fuel pump, which should share the CPL list on origin timing cover tag. Ours did not, 0187 was not on our pump 3007300 was, this matched in the book but a 300 CPL has different injectors along with a couple other different parts. So as it turns out the manuals 0187 CPL is what I believe we have in both trucks, this makes sense as a military rebuild depo may change things so the one engine suits many applications and engines aren’t repaired in the field as often as they are swapped out entirely. The missing data tags on both trucks may have been intentional to avoid confusion as to what was replaced or done as a change. I’m not sure on this but sounds logical and at the end of the day doesn’t change anything going forward. Thanks for all the input, all is appreciated. Will chime back in when it’s back together for better or worse.

 

I’m not putting collared exhaust rods back in just to make sure this never happens. Unfortunately I’m in California so with our weather I doubt I’d ever need it to work. Maybe to help prime fuel or oil but I don’t see the need for it. Maybe one of you actually truckers know different- school a newbie if so.

 

By going backwards, I verified the actual critical components in our engine. Now there is some assumptions happening here also, I don’t know what cylinder kit is in it, I’m not 100% on the cam but the fuel pump tag, injectors and turbo seem to line up with the 0187 CPL which is for a 290. The military manual we found lists all the part numbers on the parts we took out, I can say with 100% confidence we still don’t know the engine serial number and might not ever know. I did not find any numbers stamped on or embossed in the block anywhere that could be a serial number and from what I’ve researched the nt855 sc only had the info on the timing cover tag. Maybe when one hits a rebuild shop they go ahead and stamp it so it’s not lost but these two we have don’t have any kind of identification on them. Basically when it goes back together I’m checking initial injector timing with original follower .010” gasket and confirming that .034-.038” rod lift. If it’s not in range I’m swapping gaskets to get there on all 6 cylinders. Not sure how to adjust if it’s out between paired cylinders but I can swap rollers or lever arms to try to get things as matched as possible. From what I understand as long as they are all in sync with each other and one pair isn’t trying to advance or retard too much and work against the other 4 cylinders it will be content- if it’s way off but even of course it won’t be too happy but I’m not a democrat, I’m capable of critical thinking and can get her sorted out. I fell going through this the correct way is going to get it running better than the next guy that just slaps on gaskets sets overhead and goes without understanding what he’s doing. I’ve seen many videos of guys just ripping off a gasket putting a new one on with rtv smeared everywhere and it seems to work fine, so I feel like I’ve got a bit of a head start having a firm understanding of what’s actually happening.