EK1 1.8L ENGINE

From G1 Prelude

The EK1 (or EK) 1.8l engine was manufactured by Honda Motor Company between 1979-1983 for the 1st generation Honda Accord, 1st generation Honda Prelude, 1st generation Honda Vigor and early 2nd generation Honda Accord models. Introduced new for the 1979 model year, it replaced the standard EF 1.6L in US Accords. It was a water cooled, SOHC 12-Valve CVCC engine with a displacement of 1.8L (1751CC). Output varied as the engine went through two updates during it's production. Most notably was the introduction of the CVCC-II emission setup in late 1980 models. The EK 1.8l engine was standard in Japanese and US Markets. All other markets worldwide had standard the EL 1.6L engine. Transmission choices were an automatic 2spd/3spd or manual 5 speed.

Minor engine issues are known to occur, especially the cylinder head warping, causing a blown head gasket. The immense heat generated from the combined exhaust/intake setup could not exchange fast enough to the iron block, resulting in warpage. Honda tired to remedy this with an updated cylinder revision to help dissipate the heat, which lowered temps dramatically. Clogged CVCC valves and incorrect wear on the oil pump gear are also issues to look for.

Overview

  • Displacement 1.8 L (1,751 cc)
  • Inline four cylinder, transverse
  • 77mm bore x 94mm stroke (3.03 in × 3.70 in)
  • Cast iron block & aluminum cylinder head
  • Redline limit - 6,000 RPM
  • Three barrel Keihin Carburetor w/ auto choke
  • Electronic Ignition
  • Belt driven timing gear
  • Liquid Cooled - Thermostat controlled fan
  • Electric Fuel Pump
  • Oil Cooler (or provision on the block)
  • HF-3 = Automatic / HF-5 = Manual

Engine Block

Cast iron block with integrated water pump insert and large oil passages. Essentially a stroked EL Block (casting is 99% identical).Three versions exist (689, PB2 PC1) with additional manufacturing refinements and accessory bolt holes. Blocks are identical for both manual and auto trans per there version.

Specs

  • 77mm bore x 94mm stroke (3.03 in × 3.70 in)

Versions

  • 689 - #HMC-1 or HMC-3, Standard layout for 689 cylinder head (79-80 models)
  • PB2 - #HMC-3,
  • PC1 - #HMC-3, Block head surface changed. Oil cooler joint w/ drain bolt added underneath oil filter location (auto only). 12mm drain bolt w/ washer changed on front of block for additional coolant drain.

1979 - 1980 CVCC Cylinder Head (689)

Six port cylinder head (4 intake ports / 2 exhaust ports) for 1979 and 1980 models.

  • USDM EK1-1500001~ Prelude (1979 49 S)
  • USDM EK1-1000001~ Prelude (1979 CALI)
  • USDM EK1-1900001~ Prelude (1979 HI-AL)
  • USDM EK1-2500001~ Prelude (1980 49 S)
  • USDM EK1-2000001~ Prelude (1980 CALI Manual)
  • USDM EK1-2300001~ Prelude (1980 CALI Auto)
  • USDM EK1-2900001~ Prelude (1980 HI-AL)
  • JDM EK-1000001~ & EK1200001~ Engines Prelude (SN100-110 Models)
  • Note - 1980 California Automatic models used the newer PB2 cylinder head design only during this year for emission standards.
  • Intake valve diameter (34mm), Exhaust valve diameter (28mm). Aux valve diameter (12mm).

Specs

  • 8:0:1 Compression
  • 72 HP @ 4500 RPM
    • 68 HP @ 4500 RPM w/ Hondamatic '79 & '80 Models
  • 94 ft lb Torque @ 3000 RPM
    • 94 ft lb Torque @ 3500 RPM w/ Hondamatic '79 Model
    • 94 ft lb Torque @ 2500 RPM w/ Hondamatic '80 Model

Engine Weight w/ Trans

  • 5spd - 338.5lbs (153.5kg)
  • Auto - 338.7lbs (153.6kg)

689 Cam Profile

Two camshaft profiles were used on the manual/auto for these years. NOTE - '80 CALI models used the PB2 Cam profile with newer engine.

  • MANUAL TRANS CAM# 14110-689-000
    • AUX IN CAM HEIGHT - 43.737 - 44.057MM
    • MAIN IN CAM HEIGHT - 37.923 - 38.163MM
    • MAIN EX CAM HEIGHT - 38.004 - 38.244MM
  • AUTO TRANS CAM# 14110-689-900
    • AUX IN CAM HEIGHT - 43.737 - 44.057MM
    • MAIN IN CAM HEIGHT - 37.546 - 37.786MM
    • MAIN EX CAM HEIGHT - 37.628 - 37.868MM

Japanese versions of the 689 used different profiles throughout the two years.

  • 79 Manual JDM# 14110-689-000
  • 79 Auto JDM# 14110-689-900
  • 80 Manual JDM# 14110-689-010
  • 80 Auto JDM# 14110-689-901

Notes

Brand new for 1979 Accord and Prelude models, it essentially was a beefier version of the previously used EF 1.6l cylinder head on a longer block.

1981 CVCC-II Cylinder Head (PB2)

Eight port cylinder head (4 intake ports / 4 exhaust ports) for 1981 models.

  • USDM EK1-3500001~ Prelude (49 S)
  • USDM EK1-3000001~ Prelude (CALI)
  • USDM EK1-3900001~ Prelude (HI-AL)
  • JDM EK-1300001~ Engines Prelude (SN200 Models)
  • Introduction of the new CVCC-II emission system, catalytic converter and EGR valve. Intake valve diameter increased 1mm Dia (35mm), Exhaust valve diameter stayed the same (28mm). Aux valve diameter stayed the same (12mm). The original 2 port exhaust layout was changed to 4 ports to create a greater resistance with uneven heating. Increased compression was changed 8.8:1 with a slightly deeper dished piston dome. A slightly hotter spark plug was introduced due to the newer emission setup.

Specs

  • 8.8:1 Compression
  • 75 HP @ 4500 RPM
    • 68 HP @ 4500 RPM w/ Hondamatic
  • 94 ft lb Torque @ 3500 RPM

Engine Weight w/ Trans

  • 5spd - 342.8lbs (155.5kg)
  • Auto - 392.6lbs (169kg)

PB2 Cam Profile

One camshaft profile was used on both manual/auto for this year. USDM# 14110PB2020 / JDM# 14110PB2010

  • AUX IN CAM HEIGHT - 33.328 - 33.648MM
  • MAIN IN CAM HEIGHT - 37.923 - 38.163MM
  • MAIN EX CAM HEIGHT - 38.004 - 38.244MM

Notes

Redesign of the auxiliary valve across all 1981 Honda engine families for the CVCC-II update. Auxiliary chamber was brought closer to the combustion area for more efficient burning. Aux collar features five "torch" holes for mixture burning with a progressive wound spring and thicker valve holder. Piston crowns are dished per the newly updated compression ratio.

1982 - 1983 CVCC-II Cylinder Head (PC1)

Eight port cylinder head (4 intake ports / 4 exhaust ports)

  • USDM EK1-4500001~ Prelude (49 S)
  • USDM EK1-4000001~ Prelude (CALI)
  • USDM EK1-4900001~ Prelude (HI-AL)
  • JDM EK1-1400001~ Engines Prelude (SN300 Models)
  • Revised intake and exhaust spacing for better heat distribution and exhaust flow. This was done to better isolate the exhaust valves.
  • Intake valve diameter increased by 1mm (36mm), Exhaust valve diameter increased by 2mm (30mm). Aux valve diameter (12mm). Piston is slight deeper dished than PB2 pistons, but not by much.


Specs

  • 8.8:1 Compression (9.3:1 debatable per technical bulletin)
  • 75 HP @ 4500 RPM
  • 96 ft lb Torque @ 3000 RPM

Engine Weight w/ Trans

  • 5spd - 351.6lbs (159.5kg)
  • Auto - 392.6lbs (169kg)

PC1 Cam Profile

Two camshaft profiles were used on the manual/auto for this year. Manual USDM# 14110-PC1-020 / Auto USDM# 14110-PC1-902

  • AUX IN CAM HEIGHT - 33.328 - 33.648MM
  • MAIN IN CAM HEIGHT - 37.923 - 38.163MM
  • MAIN EX CAM HEIGHT - 38.004 - 38.244MM

Japanese versions used two camshaft profiles (PC2) for the manual/auto. Manual USDM# 14110-PC2-010 / Auto USDM# 14110-PC2-901. Not much is known about these cams compared to the PC1 versions.

Notes

82-83 EK/EL heads are not compatible with 79-81 EK/EL heads due to a change in block changes. As you can see in the picture below (blue felpro gasket is the 82-83 head), the two rear head bolt locations and coolant passages are different, making it impossible to put a newer head on an older block.

The newer cylinder head design created a change in combustion efficiency across the board for all 1982 Honda engine families. The intake and exhaust valve angles were slightly changed and the roof of the combustion chamber is lowered by 1.4mm. This head can only be used on an 82-83 block, but will not fit 79-81 blocks.


Engine & Transmission Serial Numbers

USDM MARKET

JDM MARKET

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