🛠️ Step 1: Pre-Installation & Core Component Swaps

Before diving into the mechanical work, you'll need to disassemble specific Gen 2 parts to accommodate the optimized Gen 3 architecture found in the official upgrade kit.

• Remove Legacy Components: Carefully dismantle the old gear, thrust bearing, camshaft rod, and all original cams from your Gen 2 engine.
• Upgrade the Camshaft Bracket: Because Gen 3 upgrade parts feature updated width and length dimensions, you must use the new, upgraded camshaft bracket included in the kit for a flawless fit.
• Piston & Connecting Rod Assembly: Swap out the old connecting rod and install the newly designed piston. Secure the piston pin evenly with zero protrusion to prevent premature cylinder liner wear.
• Piston Ring & Seal Orientation: The front sealing ring faces forward, and the rear ring faces backward. Apply a light layer of engine oil to the piston skirt for smooth insertion and optimal compression.

🚰 Step 2: Precision 3D Fuel Line Shaping & Plumbing

Miniature diesel models require precise plumbing. Avoid forcing or aggressively bending raw tubing.

• Shaping the 3D Fuel Line: Out of the box, the raw fuel line is flat. Hand-bend it into a precise 3D shape tailored to the engine block with four clean 90-degree bends. Once secured, the line must be completely rigid and motionless to prevent vibration-induced fatigue.
• Connecting to the Check Valve: Screw the adapter nut from the upgrade kit onto the oil pump check valve. Slide the nut onto the fuel line first, followed by the brass sealing ring (ferrule), guide it down through the support rod, and thread it into place.

💨 Step 3: Complete Air Bleeding (The Crucial Step!)

If your miniature diesel engine fails to build pressure or pump fuel, trapped air is almost always the culprit.

1. Crack the Bleeder Screw: Slightly loosen the bleed screw on the oil pump so the line has minor play (do not remove it entirely).
2. Prime the System: Press the fuel tank inlet to force fuel into the line. Manually operate the pump until fuel flows continuously from the far end of the pipe with zero air bubbles.
3. Lock It Down: Once solid fuel streams out without sputtering, tighten the bleed screw securely. You should feel firm, unyielding hydraulic resistance when pressing the pump.

🔬 Step 4: Piston Insertion & Cylinder Head Assembly

Because diesel engines rely entirely on high compression ratios, airtight seals are non-negotiable.

• Seating the Piston: Lubricate the piston assembly and guide it into the cylinder liner. Use your finger to support and gently leverage the piston so that only the first ring groove pops out. Rotate and ease the rubber seals into place, then tighten the rear connecting rod bolts.
• Cylinder Head Installation: Do not forget the O-ring! Always install the sealing O-ring with the countersunk hole facing downward. Secure the 4 head bolts using a cross-pattern (diagonal) sequence.
• Installing the Injector: If you lack a custom slotted mini-wrench tool, remove the cylinder head first, thread the fuel injector in tightly, check the fine threads, and then remount the entire head assembly.

⚙️ Step 5: Valve Timing & Injection Pump Timing Tuning

Achieving proper timing is what separates a smooth-running scale model from a smoking, misfiring engine.

• Valve Timing: Set the crankshaft to Bottom Dead Center (BDC), nudge it 5 to 10 degrees past, and lock down the exhaust cam so the valve closes precisely at Top Dead Center (TDC). Follow suit for the intake cam as the piston transitions into the intake stroke.
• Injection Pump Timing: Position the crankshaft right at the start of the intake stroke (TDC). Align the oil pump cam so it points vertically straight up, then lock it down.

🏁 Step 6: Pressure Relief Valve & First Fire-Up

• Install Relief Valve: Mount the special pressure relief valve (designed by hobbyist Dalun) onto the assembly.
• Pre-Lube & Warm-Up: Before your first cold start, always double-check that your engine is filled with fresh lubricating oil.
• Final Adjustments: Spin the flywheel manually. If excess fuel spits out of the exhaust, back off the oil pump adjustment until the spray pattern is ultra-fine. Let your freshly upgraded D16 Gen 3 idle, pre-heat, and run smoothly!