MAN marine pistons
The piston turns combustion into motion, sealing the cylinder on its ring pack and passing the load down the connecting rod. We supply genuine MAN pistons and piston kits for D-Series marine diesels, in standard and undersize grades, matched to your exact engine.
Pistons
Genuine MAN pistons with the engines they fit. Bore sizes, ring packs and grades vary across the D-Series, so confirm the exact reference against the model and serial number on your engine’s data plate.
| Part no. | Description | Engine / application | Availability |
|---|---|---|---|
| 51.02500-6370 | Piston |
| In stock |
| 51.02500-6394 | Piston |
| In stock |
| 51.02500-6483 | Piston 126 |
| In stock |
| 51.02500-6106 | Stationary engine piston 128.00 mm |
| In stock |
| 51.02511-7113 | Engine piston kit 128.00 mm normal |
| In stock |
| 51.02511-7221 | Engine piston kit 128.00 mm normal |
| In stock |
| 51.02511-7164 | Stationary engine piston 128.00 mm normal |
| In stock |
| 51.02500-6116 | Stationary engine piston 128.00 mm |
| In stock |
| 51.02500-6099 | Stationary engine piston 128.00 mm normal |
| In stock |
| 51.02500-6559 | Engine piston kit 138 |
| In stock |
| 51.02511-7342 | Engine piston kit 128.00 mm |
| In stock |
Click a part number for full specifications, the parts diagram and to request a quote. Not sure of the grade or size? Send us your engine model and serial number and we’ll confirm the correct piston before anything ships.
Pistons: what to check and when to replace
The piston is where the engine does its work. Combustion pressure pushes on the crown, the piston passes that force down the connecting rod to the crankshaft, and the ring pack does two jobs at once: sealing the burning gases above and controlling the oil film on the liner below. On a MAN D-Series marine diesel the crown, rings and pin all live in a very hot, high-pressure place, and they wear as a set.
Pistons and rings wear slowly with hours, but they fail early from overheating, detonation, poor oil control or a worn liner. The signs are blue oil smoke, blow-by past the rings, lost compression and power, and a knock from the top end. Because the piston and the bore wear together, a tired piston almost always means the liner needs measuring too.
MAN supplies these as bare pistons and as complete piston kits with rings, pin and circlips, in standard and undersize grades to match a reground bore. Getting the grade and size right for your engine and its overhaul history matters as much as the part number.
Our recommendations for piston work:
- Replace pistons, rings and pins as a matched set, and always fit new circlips
- Measure the liner or bore and choose the correct standard or undersize grade
- Confirm the exact reference against the model and serial number on your engine’s data plate
- Establish why the old piston wore, whether cooling, oil or fuelling, before the engine runs again
We supply genuine MAN pistons and piston kits with a 2-year warranty and worldwide dispatch. Send us your engine model and serial number, or a photo of the data plate, and we will confirm the correct piston and grade for your engine before anything is ordered.