CM871 kickin my Butt

[Waterloo]

I was looking and straining my eyes... No scissor gear there, and I think Rawze, and I know I would, have told you to replace it with what you currently have on there. I did see the old retaining plate... You are lucky you do not have that scissor gear, mine was ready to blow apart. We replaced it with a solid gear like you have on there, which was around $400! YIKES!

When you go to assemble the cam gears, make sure you use the Green Loc-Tite that Cummins calls for. You apply to the OD of the camshafts surface that contacts the ID of the gears when you go to put this all together. What is it, 609? I know that it is a favorite of bicycle shops, and sometimes can be difficult to find. Rawze found it at https://www.mcmaster.com/loctite/retaining-compounds/ there in Atlanta if you cannot locate any. It is extra protection to prevent cam gear slippage. The small bottle will suffice, as it is not cheap, and once open, you probably never need it again, it drys out quickly.

And best for two of you to remove and install those cams, the edges in that head are sharp, like razor sharp. An extra set of hands will make everything go a lot smoother.

When you go to install the front cover, I went to the hardware store and found two bolts that fit the front structure holes, cut the heads off and used those as guide pins when I had to fix a leak last year in that top cover. Near as I can figure, the plate was slightly warped, enough to cause a tiny leak, which sent oil everywhere under the hood over time. I discovered it using UV Dye for oil from NAPA, only way I could locate where it was coming from.

When I got everything apart, the gasket looked fine, no pinch marks and it was seated in that groove. So, I used some high heat RTV and laid a thin bead all the way around the outside of the gasket itself on the aluminum structure. I installed the two bolts and simply guided the plate back into place, installed bolts and torqued in the sequence recommended by Quickserve. Leak is fixed. I did use anti-seize on those bolts for the structure when I put everything back together. ;-)

Pay attention to this comment! That front structure gasket, when you go to fit it in that groove, it will need to be cut to fit, as it is an inch or two too long... When you trim that, make sure you have a grip on that end, I didn't the first go around in Rawze's driveway, and that piece fell into the front structure and dropped clear into the oil pan. Tip, if you have the oil pan off, install the oil pan when the top end is completed and ready to take oil, after it is all buttoned up. Trust me on that. Oil Pan LAST! If the pan is on, watch that lose piece of gasket, it can get away from you quickly, as it is as thin as a piece of pencil lead and is slippery as a wet noodle, it can and will ruin your day.

I also discovered the gasket at the oil fill neck was old and heat soaked, very brittle, I replaced that too. I still get a bit of oil seeping out from there, but it is manageable, I think I need a new neck to go with that new gasket, as it is plastic and more than likely getting old from time and engine heat and losing it shape.

Your crankshaft damper, if it is original, I would replace now when everything is apart. The viscous fluid in them hardens over time and will start giving you vibrations in the motor as it has lost its mojo... Cummins recommends replacing at 500,000 miles. They need to be painted too when installed, or no warranty from Cummins. I think they are still running around $650 nib. I would stick with Cummins on this part, OEM.