________________________________________________________________________________

Continental F135 Engine

The Continental F135 is a rugged, industrial four-cylinder, four-stroke, spark-ignition internal combustion engine belonging to the legendary "Red Seal" family of L-head (side-valve) engines. Characterized by its flathead cylinder block construction where all valvetrain components are contained inside the block, the F135 delivers dependable power with a low vertical profile. This design provides high structural rigidity, minimal moving parts, and simpler maintenance, making it a preferred power source for heavy-duty applications including material handling equipment (such as Clark, Hyster, Allis Chalmers, and Yale forklifts), agricultural tractors, and stationary industrial power units.

The engine features a side-valve (L-Head) configuration with 8 valves total (2 per cylinder). The intake and exhaust valves are arranged vertically in a side pocket of the cylinder block, operated directly by mechanical tappets (lifters) from a single gear-driven camshaft. This eliminates the need for pushrods or overhead valvetrain components. Bore: 3.125 inches (79.38 mm). Stroke: 4.375 inches (111.13 mm). Total Displacement: 135 cubic inches (2.2 Liters).

The engine is configured to run on either industrial pump gasoline or Liquefied Petroleum Gas (LPG) using a heavy-duty single-barrel updraft carburetor. Fuel delivery is handled by a mechanical, camshaft-driven diaphragm fuel pump. Engine speed is tightly regulated against changing loads by a mechanical flyweight-type governor connected via an adjustable linkage directly to the carburetor throttle shaft. The intake manifold is cast adjacent to the exhaust manifold to form a "hot spot" that facilitates uniform fuel vaporization and consistent cylinder air-fuel distribution.

The F135 utilizes a full-pressure lubrication system driven by a positive-displacement, gear-type internal oil pump. Oil is forced under continuous pressure through drilled internal galleries directly to all main bearings, connecting rod journals, camshaft bearings, mechanical tappets, and the timing gear assembly. Piston and Pin Lubrication: Piston pins and cylinder walls are lubricated via a metered spit-hole on the large end of the connecting rod webs, which sprays oil to prevent scuffing during cold-weather engine warm-up.

Thermal regulation is managed by a forced-circulation liquid cooling system. A belt-driven centrifugal water pump circulates coolant through the cylinder block and cylinder head water jackets. Temperature Control: Flow is regulated by a pellet-type thermostat and a built-in internal bypass channel. During the warm-up cycle, the thermostat blocks flow to the radiator, routing coolant through the bypass to reach optimal operational temperatures quickly and minimize engine wear.

General Technical Data

Engine Specifications

Engine Model ............... Continental F135
Engine Type ............... 4-cycle inline 4-cylinder side-valve L-head liquid-cooled gasoline
Number of Cylinders ............... 4
Cylinder Arrangement ............... In-line vertical
Engine Bore, in (mm) ............... 3.125 (79.375)
Engine Stroke, in (mm) ............... 4.375 (111.125)
Displacement, cu.in (L) ............... 135 (2.21)
Rated Engine Power, hp (kW) ............... 32-48 (23.8-35.8)
Rated Engine Speed, rpm ............... 1800-2400
Peak Torque ............... 105-115 Nm (77-85 lb-ft) at 1200-1400 rpm
Idle Speed ............... 450-550 rpm
Operating Speed Range ............... 1200-2400 rpm
Compression Ratio ............... 6.5:1-6.8:1
Firing Order ............... 1-3-4-2
Camshaft Drive ............... Helical cut timing gears direct crankshaft mesh train
Valve Configuration ............... L-head flathead arrangement
Cylinder Block Material ............... Cast iron alloy high-tensile
Cylinder Head Material ............... Cast iron alloy high-tensile removable
Lubrication System ............... Full-pressure internal feed system
Oil Pump Type ............... Gear-driven positive displacement
Oil Filter Type ............... Full-flow spin-on bypass element integrated
Cooling System ............... Forced liquid circulation with bypass thermostat
Water Pump Type ............... Belt-driven centrifugal impeller type packed gland
Air Cleaner Type ............... Heavy-duty oil bath or dry dual-element paper
Spark Plug Model ............... Champion D16 or Autolite 386
Spark Plug Gap ............... 0.023-0.027 in (0.58-0.69 mm)
Distributor Point Gap ............... 0.018-0.022 in (0.46-0.56 mm)
Ignition Timing Setting ............... 4-6 deg BTDC
Starting System ............... Electric starter motor engagement ring gear
Electrical System ............... 12V negative ground

Fuel System

Fuel System ............... Updraft single barrel carburetor
Carburetor Manufacturer ............... Zenith or Marvel-Schebler
Carburetor Model Variant ............... Zenith 61 series or Zenith 68 series
Choke Control Mechanism ............... Manual cable actuated butterfly valve lever arm
Throttle Control Interface ............... Mechanical linkage connected to governor
Governor Type ............... Mechanical flyweight centrifugal
Governor Drive ............... Gear-driven internal timing gear layout train
Fuel Delivery Pressure ............... 3.0-4.5 psi (20.7-31.0 kPa)
Fuel Pump Type ............... Mechanical, diaphragm
Fuel Filter Assembly ............... Inline sediment bowl with screen wire element
Alternative Fuel Capability ............... Liquefied Petroleum Gas or Natural Gas
LPG Regulator System ............... Impco Model JB or equivalent
LPG Carburetor Mixer ............... Impco Model 50 or Model 100
Main Jet Size ............... 0.048-0.054 in (1.22-1.37 mm)
Idle Jet Size ............... 0.022-0.026 in (0.56-0.66 mm)
Float Setting Level ............... 1.296-1.328 in (32.94-33.73 mm)
Idle Mixture Adjustment ............... 1.25-2.0 turns

Dimensions and Weight

Overall Length ............... 29.4 in (745 mm)
Overall Width ............... 19.6 in (500 mm)
Overall Height ............... 28.5 in (725 mm)
Dry Weight ............... 415 lbs (188 kg)
Wet Weight ............... 450 lbs (205 kg)

Maintenance Data

Service Information

Compression Pressure, Minimum ............... 110-125 psi (758-862 kPa)
Max Compression Between Cylinders ............... 10 psi (69 kPa)
Oil Pressure at Rated Speed ............... 30-45 psi (207-310 kPa)
Oil Pressure at Low Idle ............... 10 psi (69 kPa)
Thermostat Opening Valve Point ............... 160-165 F (71-74 C)
Thermostat Fully Open Target ............... 180-185 F (82-85 C)
Fan Belt Tension Deflection ............... 0.50 in (12.70 mm)
Intake Valve Clearance ............... 0.012 in (0.305 mm)
Exhaust Valve Clearance ............... 0.014 in (0.356 mm)

Engine Oil and Coolant

Engine Oil Type ............... SAE 30, SAE 15W-40
API Service Classifications ................. SG/CD
Engine Lubricating Oil Capacity ............... 4.00 qt (3.78 L)
Filter Additive Volume ............... 0.50 qt (0.47 L)
Cooling System Total Capacity ............... 8.50 qt (8.04 L)

Service Intervals

Change oil and filter ............... Every 100 hours
Replace fuel filters ............... Every 200 hours
Inspect air cleaner ............... Every 20 hours
Change air cleaner oil ............... Every 50 hours
Change coolant ............... Every 1000 hours
Valve-lash adjustment ............... Every 250 hours
Distributor point inspection ............... Every 300 hours
Spark plug replacement ............... Every 500 hours
Compression test evaluation ............... Every 1000 hours
Belt tension verification ............... Every 100 hours
Governor linkage lubrication ............... Every 100 hours

Service Specifications

Cylinder Bore Diameter, Standard ............... 3.1250-3.1265 in (79.375-79.413 mm)
Cylinder Bore Out of Round Max ............... 0.0010 in (0.025 mm)
Cylinder Bore Taper, Maximum Limit ............... 0.0020 in (0.051 mm)
Main Journal Diameter ............... 2.3744-2.3752 in (60.310-60.330 mm)
Main Bearing Shell Clearance ............... 0.0015-0.0032 in (0.038-0.081 mm)
Crankshaft End Play ............... 0.0040-0.0080 in (0.102-0.203 mm)
Crankpin Journal Runout ............... 0.0005 in (0.013 mm)
Crankshaft Main Journal Runout ............... 0.0008 in (0.020 mm)
Thrust Bearing Journal Length ............... 1.248-1.250 in (31.70-31.75 mm)
Crankpin Journal Outer Diameter ............... 2.0619-2.0627 in (52.372-52.393 mm)
Connecting Rod Bearing Clearance ............... 0.0012-0.0028 in (0.030-0.071 mm)
Connecting Rod Side Play ............... 0.0050-0.0100 in (0.127-0.254 mm)
Piston to Cylinder Wall Clearance ............... 0.0025-0.0035 in (0.064-0.089 mm)
Piston Pin Diameter, Standard ............... 0.8751-0.8754 in (22.228-22.235 mm)
Piston Pin to Con Rod Bushing Clearance ............... 0.0003-0.0006 in (0.008-0.015 mm)
Piston Pin to Piston Clearance ............... 0.0001-0.0003 in (0.003-0.008 mm)
Top Ring Groove Width ............... 0.1255-0.1265 in (3.188-3.213 mm)
Second Ring Groove Width ............... 0.1255-0.1265 in (3.188-3.213 mm)
Oil Ring Groove Width ............... 0.1885-0.1895 in (4.788-4.813 mm)
Top Ring Side Clearance ............... 0.0020-0.0040 in (0.051-0.102 mm)
Second Ring Side Clearance ............... 0.0015-0.0035 in (0.038-0.089 mm)
Oil Ring Side Clearance ............... 0.0015-0.0030 in (0.038-0.076 mm)
Top Ring End Gap ............... 0.0070-0.0170 in (0.178-0.432 mm)
Second Ring End Gap ............... 0.0070-0.0170 in (0.178-0.432 mm)
Oil Ring End Gap ............... 0.0070-0.0150 in (0.178-0.381 mm)
Cylinder Head Warp Flatness Limit ............... 0.0030 in (0.076 mm)
Intake Valve Stem Diameter ............... 0.3405-0.3415 in (8.649-8.674 mm)
Exhaust Valve Stem Diameter ............... 0.3375-0.3385 in (8.573-8.598 mm)
Intake Valve Stem to Guide Clearance ............... 0.0015-0.0040 in (0.038-0.102 mm)
Exhaust Valve Stem to Guide Clearance ............... 0.0045-0.0070 in (0.114-0.178 mm)
Valve Guide Inside Diameter ............... 0.3430-0.3445 in (8.712-8.750 mm)
Valve Seat Angle ............... 45 deg
Valve Face Angle ............... 45 deg
Valve Seat Width ............... 0.045-0.065 in (1.14-1.65 mm)
Valve Spring Free Length ............... 2.188 in (55.58 mm)
Valve Tappet Barrel Outer Diameter ............... 0.6215-0.6225 in (15.786-15.812 mm)
Valve Tappet Guide Bore Block Size ............... 0.6240-0.6255 in (15.850-15.888 mm)
Valve Tappet to Block Clearance ............... 0.0015-0.0040 in (0.038-0.102 mm)
Camshaft Journal Diameter (Front) ............... 1.8725-1.8735 in (47.562-47.587 mm)
Camshaft Journal Diameter (Center) ............... 1.8100-1.8110 in (45.974-45.999 mm)
Camshaft Journal Diameter (Rear) ............... 1.2470-1.2480 in (31.674-31.699 mm)
Camshaft Bearing Clearance, Limit ............... 0.0015-0.0035 in (0.038-0.089 mm)
Camshaft End Play ............... 0.0030-0.0060 in (0.076-0.152 mm)
Cam Lobe Height (Intake) ............... 0.276 in (7.01 mm)
Cam Lobe Height (Exhaust) ............... 0.282 in (7.16 mm)

Tightening Torques

Cylinder Head Bolts ............... 50-55 lb-ft (68-75 Nm)
Connecting Rod Cap Bolts ............... 35-40 lb-ft (47-54 Nm)
Main Bearing Cap Bolts ............... 75-80 lb-ft (102-108 Nm)
Flywheel to Crankshaft Bolts ............... 55-60 lb-ft (75-81 Nm)
Flywheel Housing to Block Bolts ............... 35-40 lb-ft (47-54 Nm)
Oil Pan Sump Perimeter Bolts ............... 12-15 lb-ft (16-20 Nm)
Oil Pan Sump Bottom Drain Plug ............... 25-30 lb-ft (34-41 Nm)
Timing Gear Cover Front Bolts ............... 15-18 lb-ft (20-24 Nm)
Camshaft Thrust Retainer Plate Bolts ............... 20-25 lb-ft (27-34 Nm)
Manifold Intake Exhaust Clamp Nuts ............... 25-30 lb-ft (34-41 Nm)
Water Pump Body Mounting Bolts ............... 15-18 lb-ft (20-24 Nm)
Valve Cover Inspection Plate Screws ............... 8-10 lb-ft (11-14 Nm)
Spark Plug ............... 25-30 lb-ft (34-41 Nm)
Distributor Hold Down Clamp Bolt ............... 10-12 lb-ft (14-16 Nm)
Fuel Pump Mounting Flange Hardware ............... 15-18 lb-ft (20-24 Nm)
Oil Pump Assembly Internal Bolts ............... 15-18 lb-ft (20-24 Nm)
Governor Housing Mounting Screws ............... 12-15 lb-ft (16-20 Nm)
Thermostat Housing Outlet Neck Bolts ............... 15-18 lb-ft (20-24 Nm)
Crankshaft Front Pulley Hub Nut ............... 110-120 lb-ft (149-163 Nm)
Generator Alternator Mounting Pivot ............... 25-30 lb-ft (34-41 Nm)
Starter Motor Flange Mounting Bolts ............... 35-40 lb-ft (47-54 Nm)
Oil Pressure Sender Galley Adapter ............... 12-15 lb-ft (16-20 Nm)
Carburetor to Intake Flange Nuts ............... 15-18 lb-ft (20-24 Nm)
Air Cleaner Bracket Support Bolts ............... 12-15 lb-ft (16-20 Nm)
Exhaust Pipe Flange Connection Nuts ............... 30-35 lb-ft (41-47 Nm)
Front Engine Mount Support Support Bolts ............... 45-50 lb-ft (61-68 Nm)
Rear Engine Mount Adapter Housing Bolts ............... 45-50 lb-ft (61-68 Nm)
Tappet Cover Gasket Thumb Screws ............... 6-8 lb-ft (8-11 Nm)
Oil Filter Center Spindle Adaptor Bolt ............... 20-25 lb-ft (27-34 Nm)

________________________________________________________________________________________

• Continental Engines Specs
  
• Continental B427 Specs
  
• Continental F124 Specs
  
• Continental F140 Specs
  
• Continental F162 Specs
  
• Continental F163 Specs
  

________________________________________________________________________________

________________________________________________________________________________________

_______________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________