MAN B&W L23/30H technical information

Four-stroke auxiliary diesel engine (generating set)

Technical description chapters of the MAN B&W L23/30H auxiliary generating sets: engine data, cross section, systems (fuel, lube oil, cooling water, compressed air, turbocharging, control and safety), fuel, lube oil and cooling water quality and treatment, operation data and alarm/shutdown set points, tightening torques, pressures and tolerances, the planned maintenance programme, operating and out-of-service instructions, crankcase ignition, and troubleshooting tables for running disturbances, starting failures, the turbine starter, lube oil cooler, cooling water and the centrifugal by-pass filter.

Click a part on the model to see its number and purpose.Open the 3D manual

Maintenance intervals

Item	When	Action	Manual
Cylinder head nuts, conrod, counterweights, bearing caps, holding-down bolts	after 200 h on new/overhauled parts	Retighten	p. 101
Inlet/exhaust valves	8000 h	Overhaul and regrind spindle and seat	p. 101
Valve clearance	2000 h	Check and adjust	p. 102
Fuel injection valves	2000 h	Overhaul and adjust opening pressure	p. 104
Turbocharger	daily/weekly	Water washing of compressor and wet cleaning of turbine side	p. 103
Lube oil	every bunkering/analysis	Samples per section 504	p. 104
Main bearing alignment (autolog)	8000 h	Measure crankshaft deflection	p. 102
Piston, rings, liner	16 000 h	Inspect, hone and measure liner	p. 101

Faults and what to do

Exhaust temperature rises on all cylindersCharge air cooler ineffective, fouled air/gas passages, poor fuel, wrong camshaft positionExhaust temperature rises on one cylinderDefective fuel valve, leaking exhaust valve, blow-by, damaged fuel camExhaust temperature drops on one cylinderAir in fuel pump, sticking fuel valve spindle, sticking pump plungerEngine rpm dropsLow fuel pressure, water in fuel, governor or valve faults, increased frictionSmoky exhaust in normal runningFouled turbocharger, defective nozzles, low air supplyExhaust valve knockingLoose adjusting screw, damaged push-rod discLube oil pressure failsPump defective, filters or cooler fouledEngine does not turn on startLow air pressure, main valve closed, pinion not engaging, start valve stuck, electrical fault

Technical specifications

Valve clearance (cold 15–55 °C)	inlet 0.50 mm, exhaust 0.90 mm	p. 33
Fuel valve opening pressure	320 bar	p. 33
Max. combustion pressure at full load	130 bar; max. 6 bar difference between cylinders	p. 33
Pmax adjustment	0.10 mm thrust-piece spacer ≈ 1 bar; 1° camshaft gear ≈ 3 bar	p. 33
Big-end bearing clearance	0.15–0.20 mm	p. 33
Main bearing clearance	0.2–0.3 mm	p. 33
Cylinder liner	new 225.000–225.046 mm, max 225.50 mm, ovality max 0.1 mm	p. 33
Crankshaft deflection (autolog)	see working card 510-01.00	p. 33
Cylinder head nuts	M45, 750 Nm (Copaslip); studs M48 200 Nm	p. 34
Main bearing nuts / side screws	M45 × 3 750 Nm / M24 300 Nm	p. 34
Counterweight screws	M30 × 2, 200 Nm + 60°	p. 34
Fuel valve nozzle nut	M26 × 1.5, 100–120 Nm	p. 34
Lube oil inlet pressure	3–4 bar (SAE 30) at full load; alarm 2.5 bar, shutdown below	p. 94
Lube oil temperature	after cooler 45–60 °C; alarm TAH, shutdown 85/95 °C	p. 94
HT cooling water	outlet 70–85 °C; alarm 90 °C, shutdown 95 °C	p. 94
Exhaust gas	before TC 425–475 °C; outlet cylinders average ±50 °C alarm	p. 94
Charge air	2–2.5 bar, 35–55 °C after cooler	p. 94
Starting air	7–9 bar, alarm below 7 bar	p. 94
Overspeed (750 rpm engine)	alarm 825, shutdown 815 (el.) / 860 rpm (mech.)	p. 94

Source: manufacturer's manual “MAN L23-30H technical information”, 126 pages. Page numbers refer to the original. Check against the manual on board before work.