Castrol Cyltech 100 Cylinder Oil
Specifications
| OEM | Castrol Marine | |
|---|---|---|
| Product type | Two-stroke crosshead cylinder oil | |
| Base Number (BN) | 100 mg KOH/g (ASTM D2896) | |
| SAE viscosity grade | SAE 50 | |
| Kinematic viscosity @ 100°C | 19.5 mm²/s (ASTM D445) | |
| Density @ 15°C | 0.940 g/ml (ASTM D1298) | |
| Flash point (PMCC) | 186 °C (ASTM D93) | |
| Intended fuel / application | Residual fuels (HSFO); medium and high sulphur fuels, including slow steaming | |
| Engine-OEM approvals | No Objection Letters from MAN Energy Solutions (MAN Diesel & Turbo), WinGD (Wärtsilä) and MHI (Mitsubishi) |
Technical notes
Cyltech 100 is a high-BN (100 mg KOH/g, ASTM D2896) SAE 50 cylinder lubricant for slow-speed two-stroke crosshead engines burning residual high- and medium-sulphur fuels. Its elevated alkalinity reserve neutralises the strong acids formed when combusting high-sulphur fuel oil, giving greater corrosion protection of liners and rings than 70 BN grades, particularly during slow steaming. Detergency is balanced to maintain piston and ring-pack cleanliness at the higher additive level. Suitability below 0.5% sulphur is limited; Castrol directs operators to lower-BN grades (e.g. Cyltech 40SX) for sustained low-sulphur operation. This is the original Cyltech 100 formulation, reported to be superseded by Cyltech 100f in 2025. Final grade, feed rate and fuel-sulphur selection must be confirmed with the engine OEM and Castrol.
Compliance
Carries No Objection Letters from MAN Energy Solutions, WinGD and MHI for current crosshead engine designs when used per their oil recommendation lists.
Compatibility
Other parts in this series
Related
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Frequently asked questions
- What Base Number and SAE grade is Castrol Cyltech 100?
- It is an SAE 50 cylinder oil with a Base Number of 100 mg KOH/g (ASTM D2896), confirmed on the official Castrol product data sheet.
- What fuel and engines is Cyltech 100 intended for?
- It is designed for slow-speed two-stroke crosshead engines burning residual high- and medium-sulphur fuels, including during slow steaming. For sustained operation below ~0.5% sulphur, Castrol recommends a lower-BN grade. Grade and feed-rate selection should be confirmed with the engine OEM and Castrol.
- Is Cyltech 100 approved by engine manufacturers?
- Yes. Castrol states Cyltech 100 holds No Objection Letters from MAN Energy Solutions (MAN Diesel & Turbo), WinGD (Wärtsilä) and MHI (Mitsubishi) for current crosshead engine designs.
Castrol Cyltech 100 Cylinder Oil
No public pricing — quoted per request