The Ford Dorset and Dover engines are a series of inline four and six cylinder diesel engines that were marinized by the Lehman Brothers of New Jersey. The engines were built in the United Kingdom.
| Engine | HP | Idle | 1000 | 1500 | 2000 | 2500 | 2600 | WOT |
|---|---|---|---|---|---|---|---|---|
| 4D524 | 80 | 0.4 | 0.6 | 1.1 | 2.2 | 3.8 | 4.5 | 4.5 |
| 4D50 | 80 | 0.4 | 0.6 | 1.1 | 2.2 | 3.8 | 4.5 | 4.5 |
| 4D61 | 90 | 0.4 | 0.7 | 1.2 | 2.4 | 4.3 | 5.0 | 5.0 |
| 6D363T | 120 | 0.5 | 0.8 | 1.4 | 3.0 | 5.2 | 6.0 | 6.0 |
| 6D380 | 135 | 0.5 | 0.8 | 1.3 | 2.8 | 4.3 | 6.6 | 6.6 |
| Super 90 – 254 cid | 90 | 0.4 | 0.7 | 1.2 | 2.4 | 4.3 | 5.0 | 5.0 |
| Super 135 – 380 cid | 135 | 0.5 | 0.8 | 1.3 | 2.8 | 4.3 | 6.6 | 6.6 |
| Super 185 | 185 | 0.6 | 1.0 | 1.8 | 3.8 | 6.5 | 7.5 | 7.5 |
| Super 225 | 225 | 0.7 | 1.2 | 2.1 | 4.5 | 7.8 | 9.0 | 9.0 |
| Super 275 | 275 | 0.8 | 1.4 | 2.5 | 5.5 | 9.5 | 11.0 | 11.0 |
| Super 355 | 355 | 1.0 | 1.8 | 3.2 | 7.0 | 12.5 | 14.5 | 14.5 |
*All values in GPH. Figures don't account for boat drag, sea conditions, propeller pitch/size, or efficiency losses through transmissions and bearings. WOT = Wide Open Throttle.
Lehman Super 90 Specification
4-cylinder naturally aspirated diesel — 254 cid / 4.15L
| Type | 4 cylinders in line, 4-cycle overhead valve, naturally aspirated diesel |
| Bore / Stroke | 4.22 in × 4.52 in (107 × 115 mm) |
| Displacement | 254 cu in (4.15 L) |
| Gross Power | 90 bhp @ 2,600 RPM |
| Compression Ratio | 16:1 |
| Fuel | ASTM D975 Class 2-D or BS 2869 Class A1 |
| Oil Capacity | 11.5 US quarts (10.6 L) initial fill |
| Oil Filter | Full-flow disposable cartridge, spin-on |
| Fuel System | In-line fuel injection pump, engine-oil lubricated, mechanical governor, flexible braided fuel supply line |
| Electrical System | 12 V negative ground with stop solenoid (24 V and insulated return available) |
| Starting Motor | 12 V electrical solenoid (24 V available) |
| Alternator | 70 amp with voltage regulator |
| Raw Water Cooling | Tubular copper / cupro-nickel heat exchanger with zinc pencil anode; optional 80% or 100% keel cooling |
| Raw Water Pump | Gear-driven high-flow rubber impeller |
| Fresh Water Cooling | Pressurized fresh water circuit for engine and exhaust manifold |
| Freshwater Capacity | 15.84 US quarts (15 L) |
| Engine Mountings | In-line, stepped, or transmission-mounted adjustable anti-vibration mounts |
| Max Install Angle | 15° rear down, 4° nose down |
| Dry Weight (less transmission) | 1,080 lbs (490 kg) |
| Exhaust Outlet | 30° water-cooled exhaust elbow or straight dry exhaust flange |
| Transmissions | Borg Warner, Newage PRM (others on request) |
| Finish | Lehman Red with chrome rocker box, air filter, and filler caps |