Ford Lehman · Inboard diesel

Ford Lehman 120

The Ford Lehman 120 is a naturally aspirated six-cylinder marine diesel that Lehman built on Ford’s Dorset industrial six 2715E; Lehman’s model code is 6D380, and the four-cylinder sister is the Lehman 80 (4D254, Ford 2712E). From 1982 Lehman’s ‘Super’ range took over with the SP135 on the Ford Dover 2725E (6.22 l, 135 hp at 2600 rpm) and the four-cylinder SP90, and Grand Banks switched its GB32, GB36 and GB42 from the 120 to the 135 in April and June 1984. The 120 and the SP135 share oil and fuel filters, belt, zincs, impeller and thermostat, but not the air filter, heat exchanger, exhaust elbow, raw-water pump, coolant pump or head gasket, so the notes say which engine a number belongs to. Lehman no longer builds engines; American Diesel Corp. in Kilmarnock, Virginia, founded in 1981 by Bob Smith, Lehman’s former head, still supplies parts, cruise kits and printed manuals. The turbocharged SP185 to SP275 and the later ‘Sabre Lehman’ engines are not covered here.

Manuals & documents

Lehman no longer exists, so there are no maker downloads. Most links lead to American Diesel Corp., the Lehman specialist: its spare-parts lists and new-owner sheets (PDF) and its order page for the printed Lehman and Ford manuals. Add to that two parts dealers that still list Lehman numbers (Lancing Marine in England, Hardin Marine in California), Jabsco’s impeller cross-reference and Grand Banks’ archived change log. We host no manuals.

Wear parts & part numbers

PartOEM numberAlso fitsNote
Engine oil filter2N501,2,3,4—Spin-on full-flow filter for the 120, SP90 and SP135; ADC sells it as 832-0050. On SP engines built from 1987 check whether the larger 2N53 is fitted (next row).
Engine oil filter2N534,5—Larger filter with revised fitting, introduced by Lehman during 1987 on the SP90 and SP135. Not interchangeable with the 2N50; engines with the 2N53 have a sticker on the owner’s manual cover. Lancing Marine still sells it.
Fuel filter (engine)61497171,2,3,4—Ford element for the twin secondary fuel filter, two per engine, on the 120, SP90 and SP135; ADC sells it as FP6149717. Use new sealing rings and bleed the fuel system afterwards.
Air filter1F11—Lehman 120 (ADC 815-0001). One dealer source.
Air filter1F74,2,3,5—Polyurethane foam element of the chromed SP90/SP135 air cleaner (ADC 815-0007). Lehman advises replacing rather than cleaning it; if you wash it, use mild detergent and water, never solvent or fuel.
Raw water pump impeller1210-00014,1,2,3,6,7Johnson Pump 09-1027B1,2,3,6,7Jabsco impeller as listed in Lehman’s breakdown of the SP pump 2C48. ADC lists the Johnson 09-1027B, with the Jabsco 1210-0001 as alternative, for the 120, SP90 and SP135; Jabsco’s cross-reference pairs the two.
Pump cover gasket32984—Jabsco end-cover gasket of the SP pump 2C48 (Lehman breakdown); included in service kit SK239.
Service kitSK2394,2,3—Jabsco service kit for the SP pump 2C48: end-cover screws, gasket, impeller and spline seal (Lehman). ADC sells it as LSK239 for the Jabsco pump only.
Raw water pump wear kit (cover, cam, seals)510-12341,2,3,8—ADC rebuild kit with cover, cam and wear plate; fits the Jabsco and the Johnson pumps of the 120, SP90 and SP135 (ADC number).
Raw water pump510-02011,9,5replaces 2C45Jabsco 10950-24015,7Lehman 120: ADC’s one-piece pump and drive assembly with gear, which replaces the original pump 2C45 on the D365 drive. It carries the Johnson pump 822-0148 (repair kit 09-45583). ADC number. Lancing Marine lists the Jabsco pump 10950-2401 (impeller 1210-0001, drive gear not included) for the 2C45 and the 6D380.
Raw water pump2C484,2,3,8Jabsco 10950-24015,7SP90/SP135: pump without gear, 7/8 in shaft; Lehman fitted a Jabsco, ADC now supplies a Johnson pump as 822-0148. Drive gear Lehman 2B102 (ADC FP6107133); ADC’s complete pump with gear is 510-0211. Lancing Marine lists the Jabsco 10950-2401 for the SP90/SP135, gear extra.
Water pump repair kit09-455831,2,3,8—Johnson repair kit for the pump 822-0148 that ADC supplies for the 120 (inside 510-0201) and for the SP90/SP135.
Alternator V-belt2B2091,2,3,4,5—V-belt for alternator and water pump on the 120 and SP90/SP135 with the standard alternator (ADC 821-0209).
Thermostat2C352,3,1,4—77 °C thermostat that ADC sells as 822-0377 for the 120, SP90 and SP135; Lehman describes 2C35 as a modified Ford thermostat.
Thermostat gasket15413171,2,3,4,10,11—Ford gasket between header tank and cylinder head, where the thermostat sits (ADC 823-8587). ADC calls it the expansion-tank gasket on the 120 list and the thermostat gasket on the SP lists.
Heat exchanger2C211 · 2C2181,9,5,12,13—Lehman 120: 2C211 copper, 2C218 cupro-nickel (ADC 822-0211 and 822-0218); mounted at the rear of the engine, 4 in shell (Hardin Marine). ADC expects about 2000 h in salt water.
Heat exchanger2C232 · 2C2394,2,3,8,5,14,15—SP135: 2C232 copper, 2C239 cupro-nickel (ADC 822-0232 and 822-0239), mounted along the side of the engine (Hardin Marine). The SP90 has its own: 2C242 copper, 2C240 cupro-nickel.
Heat exchanger gasket2D251,2,3—Rubber end-cover gasket, two per heat exchanger, on the 120, SP90 and SP135 (ADC 823-0025).
Anode (engine)EM21A1,2,3,4,5—Zinc element of the pencil anode in the heat exchanger (ADC 822-3020; ADC’s spares list has five); the complete pencil with cap is EM21 (ADC 822-3021). Same on the 120, SP90 and SP135.
Gearbox oil cooler2C207 · 2C212 · 2C212Z1,2,3,9,8,5,16,17,18—Borg Warner gearbox oil cooler: 2C207 copper, 2C212 cupro-nickel, 2C212Z cupro-nickel with zinc (ADC 822-0207, 822-0212, 822-3212), for the 120 and SP90/SP135. On the 120 the same cooler serves engine oil and gearbox (ADC, Hardin Marine). Hardin says its 2C212 replacement does not suit the 135, while ADC lists 2C212 for the SP90/SP135 gearbox too, so compare with the cooler on your engine. ADC suggests replacing it at 1200 h.
Engine oil cooler2C235 · 2C2362,3,8,4,5—SP135 engine oil cooler: 2C235 copper, 2C236 cupro-nickel (ADC 822-0235 and 822-0236). SP90: 2C233 copper, 2C238 cupro-nickel.
Exhaust mixing elbow1A3711,9,5—Lehman 120: elbow with 3.5 in OD hose bib (ADC 810-0371; kit with gasket and bolts 510-0301). Some installations need the elbow with 3 in female pipe thread, ADC 810-0283.
Exhaust mixing elbow1A3974,2,3,8,5—SP90/SP135: 30° water-cooled exhaust outlet with 3.5 in hose bib. Originally cast iron, now supplied in stainless steel under the same number (ADC).
Exhaust elbow gasket1C434,2,3,8—Gasket under the SP exhaust outlet 1A397 (ADC 812-0043).
Cylinder head gasket15748571—Lehman 120 (Ford number; ADC FP1574857). One dealer source.
Cylinder head gasket61038134,2,3—SP135 (Ford number; ADC FP6103813). The SP90 takes 6103811.
Gasket set61588651—Lehman 120 upper gasket set with head gasket (Ford number; ADC FP6158865). The complete base-engine set is FP1579279, the sump set FP6104238.
Gasket set61349592—SP135 top gasket set with head gasket (Ford number; ADC FP6134959). Lower set FP6134954GP; the sump set FP6104238 is the same as on the 120.
Fuel lift pump60387181,2,3,4—Ford fuel lift pump with gasket, the same number on the 120, SP90 and SP135 (ADC FP6038718). On naturally aspirated SP engines Lehman describes a diaphragm pump with hand priming lever.
Coolant pump50049851—Lehman 120 coolant pump with gasket (Ford number; ADC FP5004985). One dealer source.
Coolant pump16024214,2,3,19—SP90/SP135 coolant pump (Ford number; ADC FP1602421 with gasket).
Stop solenoid2E2154,2,3,1,9—12 V negative-ground stop solenoid of the SP engines (Lehman, which lists other solenoids for insulated-return and 24 V systems). ADC sells it as 824-0211; for the 120 (where ADC’s list gives Lehman 2E211 for the same 824-0211) it comes in kit 510-0530, which replaces the old box-type stop.
Damper coupling (flywheel to drive)2L74,1,2,9,8,5—Drive damper plate between flywheel and Borg Warner (Velvet Drive) or Twin Disc 502 gearbox (Lehman, Lancing Marine); ADC sells it as 830-0007 for the 80/120 and SP90/SP135. For PRM gearboxes check the type: the 301/401 and 310 take 2L11 and 2L12, the 401/402C again 2L7 (Lehman, Lancing Marine).
Engine mount2M324,8,5—Lehman resilient mount for the SP90/SP135; Lehman lists it with the lighter-rated 2M22, ADC as the Lehman mount next to its own 831-0326; Lancing Marine still sells both. Inspect the mounts and realign the shaft (ADC).

Numbers checked against the sources below on 23 October 2026. Always confirm against your serial number and exact type before ordering.

Service intervals

TaskInterval
First serviceRun in gently: 15 min idle, 15 min at 800, 30 min at 1000, 30 min at 1200 and 4 h at 1500 rpm. After the first 50 h change oil and filter and check zinc pencil, valve clearances, wiring and leaks (the oil chapter even asks for the first oil change after 15 h)4
Oil level checkDaily: engine and gearbox oil level, coolant level and belt tension4
Engine oil changeEvery 200 h4
Oil filterWith every oil change (200 h)4
Gearbox oil changeBorg Warner: every 200 h or at least once a season (ATF type A or Dexron; Warner also allows SAE 30)4
Fuel filterSecondary filters once a season or every 200 h, whichever comes first; bleed the fuel system afterwards4
Raw water impellerEvery 200 h4
Idle speed checkEvery 200 h4
Hoses & clampsEvery 200 h4
Engine mountsEvery 200 h4
ExhaustEvery 200 h4
Cooling systemEvery 1200 h: flush the cooling system and renew the antifreeze4
ThermostatEvery 3600 h4
AnodeCheck the zinc pencil every two weeks until you know how fast it wears; replace it once half the zinc is gone4
InjectorsNo fixed interval: service them when smoke, loss of power or hard starting points to them4
Gear oil coolerReplace at about 1200 h (dealer advice, ADC)9,8
Heat exchanger cleanRemove the end covers, look through the tubes with a light and flush if needed; ADC expects about 2000 h in salt water and advises carrying a spare after that (dealer advice)9,8

Lehman’s schedule from the owner’s manual for the SP90 to SP275 (publication 4C91C, June 1987), which is not online; American Diesel sells it in print as L4C91. The Lehman 120 has its own manual (L4C61 at ADC), which we have not seen, so compare its schedule before relying on these rows for a 120. The gearbox oil cooler and heat exchanger rows are dealer advice from ADC’s new-owner sheets.

Specifications

ModelsLehman 120 = model 6D380 on the Ford 2715E · Lehman SP135 (‘Super 135’) on the Ford 2725E · four-cylinder sisters: Lehman 80 = 4D254 on the Ford 2712E, SP90 on the Ford 2722E · turbo models SP160 to SP275 on the Ford 2726T and 2728T (not covered here)20,4,21
Years builtFord built the Dorset 2715E from 1974 to 1982 and the Dover 2725E from 1982 (Lancing Marine) · Lehman SP90 and SP135 from 1982 (Lehman’s engine-code table) · ADC dates the 120’s original 51 A alternator 1972–1981 · Grand Banks changed from the 120 to the 135 in April–June 1984 · the latest Lehman document seen here is the SP manual of June 198721,4,1,22
Cylinders6 in line, four-stroke, overhead valves, direct injection, naturally aspirated (Lehman’s SP135 data; the 120 is a six as well)4,9
DisplacementSP135: 6.22 l (380 cu in) · SP90: 4.15 l (254 cu in) · Lehman 120 (Ford 2715E): 6.2 l (dealer figure)4,21
Bore × stroke107 × 115 mm (4.22 × 4.524 in), SP90 and SP1354
PowerSP135: 135 bhp gross at 2600 rpm; SP90: 90 bhp at 2600 rpm (DIN 6270 / SAE J270, Lehman) · Lehman 120: 120 hp at 2500 rpm, the rating of the Ford 2715E (dealer figure)4,21
Rated speed2600 rpm under load (SP90 and SP135, Lehman); 2500 rpm for the Ford 2715E of the Lehman 120 (dealer figure)4,21
Compression ratio16.1:1 (SP90 and SP135)4
Firing order1-5-3-6-2-4 (SP135); SP90: 1-2-4-34
Direction of rotationCounterclockwise, viewed facing the flywheel (SP engines)4
InjectionIn-line injection pump lubricated by engine oil, with mechanical governor; four-hole injectors; timing 22° BTDC on No. 1 piston (SP90 and SP135)4
Valve clearance (hot)0.015 in (0.38 mm) inlet and exhaust, set with the engine at normal operating temperature (SP90 and SP135)4
Engine oil capacitySP135: 18.7 l (19.76 US qt), initial fill · SP90: 10.6 l (11.2 US qt)4
Engine oil gradeAPI CC or equivalent; by air temperature SAE 30 above 90 °F (32 °C), SAE 20W-20 in moderate climates, SAE 10W in the cold (SP manual)4
Coolant capacitySP135: 18 l (19 US qt) · SP90: 15 l (15.84 US qt)4
CoolingPressurised fresh-water circuit for engine and exhaust manifold; two-pass shell-and-tube heat exchanger in copper or cupro-nickel with zinc pencil; gear-driven bronze Jabsco raw-water pump with rubber impeller; operating temperature 82–94 °C, maximum 99 °C (SP engines)4
Thermostat opens at77 °C, the thermostat ADC supplies for the 120, SP90 and SP1351,2,3
AlternatorSP engines: 70 A (Lehman); many left the factory with a French-made Motorola, which ADC replaces with a 65 A unit · Lehman 120: 51 A in 1972–1981 (ADC)4,8,1
Belt tensionNo more than 1/2 in (about 13 mm) deflection under thumb pressure between alternator and water-pump pulleys (SP engines)4
Dry weightSP135: 623 kg (1374 lb) · SP90: 490 kg (1080 lb); both without gearbox4
Max. installation angleUp to 15° stern down (SP90 and SP135)4
GearboxSP135: Borg Warner, Hurth, Newage PRM or Twin Disc; SP90: Borg Warner or Newage PRM (Lehman). Damper plate and adaptor depend on the gearbox4
Exhaust outletSP engines: 30° water-cooled exhaust elbow or a straight dry-exhaust flange · Lehman 120: elbow with 3.5 in OD hose bib (ADC)4,9

Good to know

  • Know which engine you have before ordering: the 120 (6D380, Ford 2715E) and the SP135 (2725E) share oil and fuel filters, belt, zincs and impeller, but not the air filter, heat exchanger, exhaust elbow, raw-water pump, coolant pump or head gasket. On SP engines Lehman stamps the serial number on a raised pad on the expansion tank and at the front right of the timing case, a date code on a pad behind the injection pump and the cubic inches at the rear starboard side of the block.1,2,4
  • During 1987 Lehman introduced a larger oil filter, 2N53, with a revised fitting on the SP90 and SP135; it does not interchange with the 2N50. Engines with the 2N53 got a sticker on the owner’s manual cover; if yours has no manual, compare the old filter before ordering.4
  • The Borg Warner gearbox oil cooler is the critical one: when it leaks, sea water fills the gearbox, which then has to be stripped, cleaned and resealed. ADC suggests replacing it at about 1200 hours; there is a cupro-nickel version with zinc pencil, 2C212Z.9,8,1,2
  • Exhaust elbows rust from the inside. ADC advises replacing the 120’s elbow before its bottom blows out; on SP engines the original cast-iron 1A397 rusted the same way, and that number now comes in stainless steel. Pull the 3.5 in exhaust hose off the bib to inspect the water port.9,8
  • Raw-water pump: on the 120, check the D365 pump drive for a worn drive tang, a sign of failed bearings; ADC’s one-piece pump and drive with gear, 510-0201, replaces the 2C45. Lehman lists the SP135 pump assembly as a replacement for the 6D380 and 4D254 pumps as well, noting straight or helical gear. ADC suggests carrying a spare pump after 2000 hours.9,8,4
  • Above 2500 hours, have the drive damper between flywheel and gearbox inspected (Lehman 2L7, ADC 830-0007). If the rear engine mounts sit on the gearbox, the back of the engine has to be supported before the gearbox comes off.9,8,4

Videos & how-tos

Links to YouTube, nothing embedded. The maker’s own channel comes first; the rest are channels we found clear and correct for this model.

Fitted in

Boats whose builder lists it as standard or optional equipment:

  • Grand Banks 42 — Lehman 120 hp · 135 hp (Early fibreglass boats: Lehman 120 hp, Lehman 135 hp from hull 42-877 (April 1984))

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Sources

  1. img1.wsimg.com/blobby/go/adf5e9b7-e3d7-404a-bc52-39a9b19b7b49/downloads/Lehman%206D380-12…
  2. img1.wsimg.com/blobby/go/adf5e9b7-e3d7-404a-bc52-39a9b19b7b49/downloads/Lehman%20SP135%20…
  3. img1.wsimg.com/blobby/go/adf5e9b7-e3d7-404a-bc52-39a9b19b7b49/downloads/Lehman%20SP90%20(…
  4. Lehman Power, Owners Manual and Parts Identification, engine models SP90, SP135, SP185, SP225 & SP275, publication 4C91C, June 1987 (sold in print as L4C91 by American Diesel Corp.)
  5. lancingmarine.com/price-book/page-11/
  6. xylem.com/siteassets/brand/jabsco/resources/specification/impeller-cross-reference-table-…
  7. lancingmarine.com/price-book/page-33/
  8. img1.wsimg.com/blobby/go/adf5e9b7-e3d7-404a-bc52-39a9b19b7b49/downloads/New%20Owners%20Sh…
  9. img1.wsimg.com/blobby/go/adf5e9b7-e3d7-404a-bc52-39a9b19b7b49/downloads/New%20Owners%20Sh…
  10. lancingmarine.com/price-book/page-7/
  11. lancingmarine.com/price-book/page-8/
  12. hardin-marine.com/p-113558-heat-exchanger-a4601-4162-lehman-2c211.aspx
  13. hardin-marine.com/p-113561-heat-exchanger-m4602-4162-lehman-2c218.aspx
  14. hardin-marine.com/p-113555-heat-exchanger-a1233-00-lehman-2c232.aspx
  15. hardin-marine.com/p-113556-heat-exchanger-a4579-4162-lehman-2c239.aspx
  16. hardin-marine.com/p-22195-lehman-oil-cooler.aspx
  17. hardin-marine.com/p-22198-lehman-oil-cooler.aspx
  18. hardin-marine.com/p-113665-replacement-oil-cooler-a4615-2091-lehman-2c212z.aspx
  19. lancingmarine.com/price-book/page-10/
  20. americandieselcorp.com/parts-lists
  21. lancingmarine.com/price-book/page-6/
  22. web.archive.org/web/20040421053617/http://www.grandbanks.com:80/portside/bulletins/Dealer…

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