How to Build a Cummins Engine the Right Way (Part 1)

If you have ever cracked open an engine block and wondered whether you are missing something the shop guys never talk about, this episode is for you. Todd, Will, and Myer break down the real hands-on engine building process, step by step, using their Myers UCC build as the backdrop for a conversation that covers everything from the stuff you check before you turn a wrench to the stuff that will bite you if you skip it.

The episode kicks off with oil galley plug inspection, what the guys call the oil rail, oil rifle, or oil passage depending on who is talking, and why making sure every one of those plugs is seated before assembly is a non-negotiable. They get into cleaning procedures using an engine bore brush kit to pull out machining particles and metal flakes from the cylinder bores and oil passages before anything goes back together. Bearing clearances get a solid breakdown here. The guys walk through main bearings and rod bearings on a Cummins engine, explain why the oil holes in the bearings do not line up the way you might expect, and talk through what proper clearance looks like for street builds versus high RPM race applications. They also hit a detail that trips up a lot of first-time builders: rod caps are matched to their specific rod during the machining process, and swapping caps between rods will cost you roundness and likely an engine.

Cylinder wall prep takes up a good chunk of the conversation too. The guys reference using the Total Seal ring break-in compound to verify cleanliness, where green means the wall is ready and brown means you are not done yet. From there the discussion moves into piston ring gap, how they set the second ring at or slightly larger than the top ring, ring orientation during installation, and their experience running Total Seal gapless second rings at higher horsepower levels where piston land strength starts to become a real concern.

The back half of the episode covers assembly lube, specifically the Joe Gibbs Driven line and other black assembly greases the guys have had good results with, where to apply it and where not to, and the proper way to lube a camshaft, lifters, and cam lobes before the engine goes together. The cylinder head side of the build runs long and gets pushed to next week, so consider this Part 1 of a two-part deep look at what it actually takes to build a diesel engine the right way.

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Everything the guys talked about in this episode, rings, bearings, assembly products, all of it is the kind of stuff you can find at PowerDriven.com. If you are building an engine, start there.

Shop Power Driven Diesel: https://www.powerdriven.com 0:00 Intro and Mars UCC engine build overview 1:18 Oil galley plugs and why they cannot be overlooked 2:30 Cleaning oil passages and cylinder bores 4:13 Main bearing installation and oil hole alignment 5:03 Measuring journals and bearing clearances 7:07 Cylinder wall prep and final cleaning order 10:00 Total Seal break-in compound and cylinder wall verification 10:35 Measuring rod journals, main journals, and bearings 12:30 Bearing clearance specs for street vs race applications 13:24 Why race clearances and thick oil do not work on a street truck 18:33 Rod cap and rod matching on Cummins and aftermarket rods 29:52 Piston ring clearance and piston wall clearance 31:42 Ring gap setup and second ring sizing 33:34 Ring orientation during installation 40:37 Total Seal gapless second ring discussion and high HP concerns 42:06 Loctite, fasteners, and oil galley plug sealing 49:15 Assembly grease selection and application 52:25 Camshaft and lifter lubrication 53:45 Episode wrap and Part 2 preview