The Deno L2-20 is a two-stage, air-cooled, single-acting starting air compressor used to start marine and shore-based diesel engines and to feed general high-pressure air systems. Harbor Eagle supplies the full range of consumable and service parts to keep an L2-20 in class — matched by part number, quoted quickly, and shipped to the vessel or workshop.
Which Deno L2-20 parts wear first?
On a starting air compressor, the parts that come up most often in a service or overhaul are the air-side wear items: the concentric valve assemblies (plates and springs), the piston rings and oil rings, the air filter element, and the full set of gaskets and O-rings disturbed every time a cylinder head comes off. The manufacturer's own schedule recommends replacing valve springs at roughly 2,000 running hours (even if they don't look worn), checking valve plates for flatness — the wear limit is 6% of original plate thickness — and never re-using the aluminium head gasket. Those are the items worth holding or pre-quoting; everything else is available on demand.
Fast movers to keep on the shelf: Air filter element 8801A · 1st-stage valve group 7100A · 2nd-stage valve group 7200A · 1st-stage piston rings 2102B / 2103B · 2nd-stage piston rings 2202A / 2203A · LP safety valve 7500A · HP safety valve 7600A · coupling rubber set 8705A.
Deno L2-20 spare parts — part number reference
Search by the part number stamped in the L2-20 parts list, or by component name. Every number below can be quoted individually or as a service kit. If you have a number that is not listed, send it — the L2-20 shares many fittings and fasteners across groups.
| Part No. | Component | Function & notes |
|---|---|---|
| 7100A | Concentric valve group, 1st stage | Complete LP valve assembly |
| 7101A | Valve seat | LP concentric valve |
| 7102A | Valve guard | LP concentric valve |
| 7103A | Suction valve plate (small) | Wear part |
| 7104A | Suction valve spring (small) | Replace as a set at ~2,000 h |
| 7105A | Suction valve plate (large) | Wear part |
| 7106A | Suction valve spring (large) | Replace as a set |
| 7107A | Delivery valve plate | Wear part |
| 7108A | Delivery valve spring | Replace as a set |
| 7109A | Valve clamping bolt | |
| 7110A | Valve clamping nut |
| Part No. | Component | Function & notes |
|---|---|---|
| 7200A | Concentric valve group, 2nd stage | Complete HP valve assembly |
| 7201A | Valve seat | HP concentric valve |
| 7202A | Valve guard | HP concentric valve |
| 7203A | Suction valve plate (small) | Wear part |
| 7204A | Suction valve spring (small) | Replace as a set |
| 7205A | Delivery valve plate | Wear part |
| 7206A | Delivery valve spring | Replace as a set |
| 7207A | Valve clamping bolt | |
| 7208A | Valve clamping nut |
| Part No. | Component | Function & notes |
|---|---|---|
| 2101B | Piston, 1st stage (LP) | Light aluminium alloy |
| 2102B | Piston ring, 1st stage | Compression ring — wear part |
| 2103B | Piston oil ring, 1st stage | Oil scraper — wear part |
| 2104A | Piston pin, 1st stage | |
| 2105A | Snap ring, 1st stage | |
| 2201A | Piston, 2nd stage (HP) | Cast iron |
| 2202A | Piston ring, 2nd stage | Compression ring — wear part |
| 2203A | Piston oil ring, 2nd stage | Oil scraper — wear part |
| 2204A | Piston pin, 2nd stage | |
| 2205A | Snap ring, 2nd stage | |
| 4101A | Connecting rod, 1st stage (set) | Upper/lower — supplied as set 4101A |
| 4201A | Connecting rod, 2nd stage (set) | Upper/lower — supplied as set 4201A |
| 4102A | Crank pin metal / big-end bearing (set) | Upper & lower shells |
| 4103A | Piston pin bush, 1st stage | Phosphor bronze |
| 4203A | Piston pin bush, 2nd stage | Phosphor bronze |
| 4105A | Rod oil scraper | |
| 4104A | Connecting-rod reamer bolt |
| Part No. | Component | Function & notes |
|---|---|---|
| 1101B | LP cylinder head | 1st stage |
| 1102A | Gasket ring, LP head | Do not re-use — renew on assembly |
| 1103A | Head packing, LP | Renew on assembly |
| 3101B | Cylinder, 1st stage | 100 mm bore |
| 3102A | O-ring, cylinder | Common LP/HP — renew on assembly |
| 1201A | HP cylinder head | 2nd stage |
| 1202A | Gasket ring, HP head | Do not re-use — renew on assembly |
| 1203A | Head packing, HP | Renew on assembly |
| 3201B | Cylinder, 2nd stage | 45 mm bore |
| 3103A / 3203A | Stud bolt, LP / HP head |
| Part No. | Component | Function & notes |
|---|---|---|
| D6101A | Crank case | |
| 5101B | Crank shaft | |
| 6308A | Main bearing | 2 off — roller/ball |
| 6121A | Oil seal | 2 off — renew on assembly |
| 6122A | Main bearing case O-ring | |
| 6132A | Main bearing cover O-ring | |
| 6106A | Oil level gauge (sight glass) | |
| 6107A | Oil (L.O.) plug | |
| 6140B | Air vent valve | |
| 6114A | Lifting lug |
| Part No. | Component | Function & notes |
|---|---|---|
| 7500A | LP safety valve, complete | 1st stage, ~8 bar |
| 7600A | HP safety valve, complete | 2nd stage, ~31 bar |
| 8210A | Non-return valve, complete | Delivery — available as full set |
| 8212A | Non-return valve element | Wear part |
| 8213A | Valve spring, non-return | |
| 8215A | Seat O-ring, non-return | |
| D8101C | Drain separator body, 1st stage | |
| D8201B | Drain separator body, 2nd stage | |
| 8102A | Drain separator cover O-ring | |
| 9211A | Needle valve (drain) | |
| 8701A | Coupling, compressor side | Flexible coupling |
| 8703B | Coupling, motor side | Flexible coupling |
| 8705A | Coupling rubber set | Bolts, washers & rubbers — wear set |
| 7013A | Vibration damper | Anti-vibration mount |
| Part No. | Component | Function & notes |
|---|---|---|
| 8801A | Air filter element | Interchangeable — fast-moving consumable (set 8800B) |
| 8800B | Air filter, complete set | Element + both cases |
| 8550B | Fan | Axial cooling fan |
| D8510A | LP cooler pipe | Supplied with 2 flare nuts |
| D8535A | Distributor | Cooler group |
| D8556A | Fan cover |
This is a working extract of the most requested references. Harbor Eagle can quote any item across the full L2-20 group breakdown — air filter, valves, cylinders, pistons, connecting rods, crankcase, crankshaft, drain separators, non-return valve, cooler and coupling.
Service data at a glance
Buyers pricing an overhaul usually want the numbers alongside the parts. Key L2-20 figures, so you can plan the job and the order together:
| Item | Value |
|---|---|
| Type | 2-stage, air-cooled, single acting |
| Cylinder bore | 1st stage 100 mm · 2nd stage 45 mm |
| Stroke | 42 mm |
| Design pressure | 33 kg/cm² (≈32 bar) |
| Safety valve set — LP / HP | 8 ±1 bar / 31 ±1 bar |
| Crankcase oil quantity | 1.8 L (replenish line 0.6 L) |
| First oil change | After 50 running hours, then every 600 hours |
| Valve spring replacement | ≈ every 2,000 running hours |
| Valve plate wear limit | 6% of original thickness |
| Overhaul interval | Once every 2 years |
| Connection | Torque |
|---|---|
| Cylinder heads | 40.0 – 44.5 |
| Connecting rods | 70.0 – 74.5 |
| 1st stage valve | 25.0 – 29.5 |
| 2nd stage valve | 15.0 – 17.0 |
| Vibration dampers | 40.0 – 44.5 |
Frequently asked questions
What spare parts does a Deno L2-20 compressor need most often?
The most frequently replaced Deno L2-20 parts are the concentric valve plates and springs (assemblies 7100A for the 1st stage and 7200A for the 2nd stage), piston rings and oil rings (2102B/2103B and 2202A/2203A), the air filter element 8801A, and the gaskets and O-rings disturbed during head removal. Valve springs are typically renewed as a full set around every 2,000 running hours.
What is the oil change interval for a Deno L2-20?
Change the oil after the first 50 running hours, then every 600 running hours. Check oil level and condition daily. Crankcase capacity is about 1.8 litres; use a good-quality compressor oil (SAE 20/30 grade depending on ambient temperature and daily running hours).
What are the safety valve set pressures on the L2-20?
The 1st-stage (LP) safety valve is set to 8 ±1 bar and the 2nd-stage (HP) safety valve to 31 ±1 bar. Complete safety valves are available under 7500A (LP) and 7600A (HP), and performance should be checked monthly.
How do I know when a valve plate needs replacing?
Check valve plates for flatness; the maximum wear limit is 6% of the original plate thickness. Never re-use sharp-edged or grooved plates, and replace all springs in a valve at the same time. The aluminium head gasket between valve and cylinder head must always be renewed, never re-used.
Can Harbor Eagle supply a complete valve or overhaul kit rather than single parts?
Yes. Beyond single part numbers, we quote complete valve assemblies (7100A / 7200A), the air filter set 8800B, big-end bearing sets (4102A), connecting-rod sets (4101A / 4201A) and made-to-order gasket and O-ring overhaul kits. Send your compressor serial and running hours and we will scope the kit to the job.
Send us the part number — get a quote back fast
One list, one contact, worldwide delivery to vessel or workshop. Whether it's a single air filter element or a full 2-year overhaul kit for a Deno L2-20, Harbor Eagle turns your part numbers into a priced, deliverable offer.
Request a QuoteRelated pages
Sourcing engine spares alongside your compressor overhaul? See our MaK engine spare parts reference, or browse the full marine spare parts catalogue.