4105 Series Diesel Engine Parts — Generator Applications
The 4105 series is a 4-cylinder diesel engine with a 105mm bore, representing one of the larger-displacement engines in the popular 4-cylinder diesel generator family. With displacement around 4.0L, these engines power generator sets typically rated 30-80 kW, serving as reliable prime movers in construction, agriculture, marine auxiliary, and industrial standby applications.
Engine Specifications Overview
| Parameter |
Specification |
| Configuration |
Inline 4-cylinder, 4-stroke, water-cooled, direct injection |
| Bore x Stroke |
105mm x 115-125mm (varies by variant) |
| Displacement |
~3.98-4.33L |
| Compression Ratio |
16.5:1 – 17.5:1 |
| Firing Order |
1-3-4-2 |
| Power Range (Generator) |
30-80 kW (varies with aspiration and speed) |
Parts Cross-Reference Guide
| Component |
4105 Series PN Prefix |
Compatible With |
Notes |
| Piston & Ring Set |
4105-04-series |
4105 specific (105mm bore) |
Verify piston crown type: NA vs turbocharged |
| Cylinder Liner |
4105-02-series |
4105 specific |
Wet liner type; replace O-rings with every liner installation |
| Head Gasket |
4105-01-series |
4105 specific |
Thickness grade marked (A, B, C); match piston protrusion |
| Oil Filter |
JX0818 or equivalent |
4100, 4102, 4105 common |
Spin-on type; verify thread and seal diameter |
| Fuel Filter |
CX0708 or equivalent |
Multiple series compatible |
Water separator type recommended |
| Water Pump |
4105-20-series |
4105 specific |
Verify rotation direction before installation |
Frequently Asked Questions
1. How do I tell if my 4105 engine is naturally aspirated or turbocharged?
Turbocharged 4105 engines have: (1) a turbocharger mounted on the exhaust manifold, (2) an intake pipe from turbocharger outlet to intake manifold, (3) typically an oil supply line to the turbocharger center housing and an oil drain back to the oil pan, (4) different pistons (reinforced crown with a different combustion bowl shape), and (5) often piston cooling oil jets (nozzles spraying oil onto piston underside). The engine data plate will also indicate if the engine is turbocharged.
2. What is the valve clearance specification for 4105 series engines?
Cold setting (engine at room temperature, not run for 4+ hours): intake valves 0.25-0.30mm, exhaust valves 0.30-0.35mm. Adjustment procedure: rotate crankshaft to TDC of cylinder 1 (both valves closed, timing marks aligned), adjust cylinder 1 intake and exhaust, then rotate 180° and adjust next cylinder in firing order (1-3-4-2). Always recheck after tightening lock nuts.
3. Can I replace individual injectors or must I replace all four?
Individual injectors can be replaced, but best practice is to test all four and replace as a matched set if more than one shows wear. Reasons to replace all four: (1) injectors wear at similar rates — if one has failed, others are likely near end of life, (2) mismatched injector flow rates cause cylinder-to-cylinder power imbalance and rough running, (3) labor cost to access injectors makes doing all four at once more economical in the long run. Always have injectors tested (pop-tested) before deciding to replace vs. clean and recalibrate.
4. What causes the 4105 engine to vibrate excessively?
Excessive vibration in a 4-cylinder inline engine with balanced crankshaft can be caused by: (1) one cylinder not firing or weak — feel exhaust manifold branches for temperature difference (cold branch = dead cylinder), (2) failed engine or generator mounting isolators (rubber mounts or springs) — visually inspect for collapsed, cracked, or separated mounts, (3) damaged or loose flywheel, (4) severe injection timing error on one cylinder, or (5) crankshaft damper (harmonic balancer) failure — rubber element separating from metal hub.
5. Can I use biodiesel in my 4105 series generator?
Low biodiesel blends (B5-B10) are generally compatible with 4105 series fuel systems. Higher blends (B20+) present risks: (1) biodiesel is a strong solvent — it will clean years of diesel deposits from tank and lines, rapidly clogging fuel filters, (2) biodiesel can degrade older rubber fuel hoses and seals, (3) biodiesel has lower energy content (~7% less than diesel) — expect measurable power loss at B20+, and (4) biodiesel has poor storage stability — use within 6 months. If switching to biodiesel, have spare fuel filters on hand and monitor for leaks at seals.
6. What is the correct break-in procedure for a rebuilt 4105 engine?
After a major overhaul: (1) Prime the oil system by cranking with fuel shutoff until oil pressure registers, (2) Start and run at fast idle (1000-1200 RPM) for 15-20 minutes — do not idle, which causes poor ring seating, (3) Inspect for leaks during warm-up, (4) Apply progressively increasing load over the first 10-20 hours — 25% for 2h, 50% for 4h, 75% for 8h, then full load, (5) Change oil and filter after the first 50 hours, (6) Avoid extended no-load or light-load operation during break-in — piston rings seat best under moderate to heavy load.
Related Articles
Frequently Asked Questions
What is the 4105 Series diesel engine?
The 4105 Series is a 4-cylinder, 105mm bore diesel engine platform — the largest of the common 4-cylinder Chinese diesel families (4100/4102/4105). Displacement is 4.0-4.6 liters depending on stroke length, with power output of 50-90 HP naturally aspirated and 80-140 HP turbocharged at 1,500-2,200 RPM. For generator applications, the 4105 is well-suited for 20-60kW generator sets — the larger displacement provides excellent load acceptance (frequency and voltage recovery after a large load step) compared to smaller 4-cylinder engines. The 4105 is widely used in: construction machinery (wheel loaders, excavators), agricultural tractors, medium generator sets, water pumps, and marine propulsion. Key manufacturers include Yuchai, Weichai, Xinchai, Laidong, and Changchai. HUAQUAN stocks OEM-specification parts for all major 4105 variants.
What is the cylinder liner type used in the 4105 engine?
The 4105 uses wet-type cylinder liners — a replaceable sleeve that is in direct contact with the engine coolant on its outer surface. The liner is sealed at the top by the cylinder head gasket and at the bottom by 2-3 rubber O-ring seals in grooves in the lower block bore. Wet liners provide superior cooling compared to dry liners because the coolant directly contacts the liner. Replacement procedure: (1) Remove the piston and connecting rod; (2) Use a liner puller tool to extract the old liner — do not use a hammer and drift, which can damage the block’s counterbore; (3) Clean the counterbore thoroughly — any debris or corrosion left in the counterbore will prevent the new liner from seating properly, causing the liner to sit too high; (4) Install new O-ring seals on the new liner — lubricate the O-rings with clean engine oil or rubber lubricant; (5) Press the liner into the block by hand or with a liner press tool — it should go in smoothly. If excessive force is needed, stop and check; (6) Measure the liner protrusion above the block deck — typically 0.05-0.15mm. This is critical: too low and the head gasket will not seal (coolant leak, combustion leak); too high and the liner cracks when the head is torqued. Liner protrusion must be within 0.03mm across all cylinders.
What are the symptoms of a blown head gasket on a 4105?
Head gasket failure symptoms: (1) Coolant in the engine oil — the oil appears milky or like a chocolate milkshake on the dipstick. This is the most common failure mode — the gasket fails between a coolant passage and an oil drain-back passage; (2) White smoke from the exhaust with a sweet smell — coolant is entering the combustion chamber and being turned to steam; (3) Bubbles in the radiator/overflow tank with the engine running — combustion pressure is leaking into the cooling system; (4) Overheating with no other apparent cause — combustion gas in the coolant reduces the coolant’s heat transfer capacity and displaces liquid coolant; (5) Low compression in two adjacent cylinders — the gasket has failed between the two cylinders, allowing compression to leak between them; (6) External coolant or oil leak at the cylinder head-to-block joint. Confirm the diagnosis: combustion gas test kit (chemical test of radiator air for CO2), cylinder leak-down test, and compression test. A blown head gasket must be addressed immediately — coolant in the oil destroys bearings within hours of engine operation.
What is the torque specification for a 4105 cylinder head?
Cylinder head torque specification (always consult the specific manufacturer’s manual — these are representative values): (1) Tightening sequence: start from the center bolts and work outward in a spiral pattern. This ensures the head compresses the gasket evenly from the center — tightening from one end to the other warps the head; (2) Torque steps: typically 3 steps — 60 Nm, 120 Nm, 180-200 Nm final torque. Some engines use a torque-plus-angle method: initial torque (e.g., 60 Nm), then an additional 90-degree angle turn, then a second 90-degree turn; (3) Re-torque: some engine manufacturers require re-torquing the head bolts after the first 50-100 operating hours (hot re-torque) — check the manual; (4) Head bolt condition: head bolts are torque-to-yield (TTY) on some modern engines — they stretch permanently during tightening and must be replaced, not reused. Older 4105 engines typically use reusable bolts but inspect for necking or thread damage; (5) Always use a calibrated torque wrench — over-tightening pulls threads from the cast iron block; under-tightening guarantees gasket failure. HUAQUAN supplies the correct head gasket and bolt set for each 4105 variant.
What replacement parts are available for the 4105 Series?
HUAQUAN supplies the full 4105 parts range: (1) Engine block components: cylinder liners (wet type, with O-ring kit), pistons (standard and oversize), piston rings, connecting rods and bearings, main bearings, crankshaft, thrust washers; (2) Cylinder head: complete assembly, valves/intake/exhaust, valve seats, guides, springs, rocker shaft assembly, head gasket and full gasket set; (3) Fuel system: injection pump, injector nozzles and complete assemblies, fuel filter, fuel lift pump with primer, fuel lines; (4) Lubrication: oil pump, oil filter, oil cooler; (5) Cooling: water pump, thermostat, fan, radiator; (6) Geartrain: timing gears, idler gear, camshaft; (7) Electrical: starter motor (12V, typically 3.0-4.0kW), alternator, glow plugs; (8) Overhaul kits: in-frame (pistons/liners/rings/bearings/gaskets) and complete (all of the above plus valves, oil pump, water pump).
What is the oil capacity of a 4105 engine?
Oil capacity (including filter): approximately 8-12 liters depending on the specific manufacturer and oil pan configuration. Always check the dipstick after filling — the manual specification is a guide, but the dipstick is the final authority. Overfilling is as dangerous as underfilling: the crankshaft counterweights dip into the oil at high RPM, whipping it into foam (aerated oil). Aerated oil is compressible — the oil pump cannot build proper pressure, and bearings starve for lubrication. Fill procedure: add approximately 80% of the specified capacity, start the engine and run for 30 seconds to fill the filter and galleries, shut down, wait 2-3 minutes for oil to drain back to the pan, and check the dipstick. Add to the ‘full’ mark. The oil should be changed every 250 hours (standby) or 500 hours (prime power), and always with a new filter.
