Naturally aspirated 4-152
1961–1968About 90–93 hp
Original Scout four-cylinder
TorqueList Original Technical Art
International Harvester 4-152 Comanche
Inline4 · N/A
International Harvester · Comanche Four-Cylinder
International Harvester 4-152 Comanche
The Scout's original slant-four, created from one bank of International's SV V8 architecture.
152
Cubic inches
The 152 was the original Scout engine and shared major design thinking with the larger IH SV family, giving the compact utility vehicle a deliberately truck-like powerplant.
Key variants
All variantsNaturally aspirated 4-152152-T turbo
Displacement
152 ci
Bore
3.875"
Stroke
3.21875"
Years
1961–1968 Scout production era; turbocharged 152-T offered 1965–1967
Key Takeaway
The 152 Comanche was a large-displacement OHV four-cylinder built around International Harvester's truck-first design philosophy. Its 3.875-inch bore and 3.21875-inch stroke created 152 cubic inches, while heavy cast-iron construction and simple carburetion prioritized low-speed durability in the original Scout.
Technical Specifications
- Compression
- 8.1:1 class in later Scout specification
- Horsepower
- 90 hp early; 93 hp @ 4400 rpm in documented 1966–1970 Scout specification
- Torque
- 143 lb-ft @ 2400 rpm in documented 1966–1970 specification
- Architecture
- Inline/slanted OHV four-cylinder derived from IH SV architecture
- Block
- Cast iron
- Cylinder heads
- Cast iron
- Valvetrain
- Pushrod OHV
- Aspiration
- Naturally aspirated
- Fuel delivery
- Carbureted
- Firing order
- 1-3-4-2
The 152 Comanche was a large-displacement OHV four-cylinder built around International Harvester's truck-first design philosophy. Its 3.875-inch bore and 3.21875-inch stroke created 152 cubic inches, while heavy cast-iron construction and simple carburetion prioritized low-speed durability in the original Scout.
Internal Specifications
Variant-specific values are labeled. Engine families that span multiple years or RPOs can have different heads, cams, induction and rotating parts, so the exact code/year always takes priority.
Identification & Output
- Engine codes / RPO
- 4-152 / C-152 Comanche, 152-T (factory turbocharged Scout version, 1965–1967/68 era)
- Casting numbers
- No single universal block/head casting is retained across all Scout 4-152 production; verify engine stamp, 3.875 x 3.21875-inch bore/stroke, head casting and application together.
- Power rating
- SAE gross / period brake horsepower for early Scout ratings
- Horsepower RPM
- 93 hp @ 4400 rpm in documented Scout specification; earlier ratings about 90 hp
- Torque RPM
- 143 lb-ft @ 2400 rpm
Operating Specs
- Production notes
- The 152 launched with the Scout 80 and remained the core engine through the early Scout 800 period. Its bore/stroke closely parallels one bank of International’s SV-family architecture, reflecting the company’s shared heavy-duty design philosophy.
Compatibility Notes
- Do not confuse the Scout 4-152 with International tractor engines that also carry a C-152 designation; bore/stroke and application architecture differ.
- Scout 152 and 196 share related four-cylinder design ideas, but crank, bore/stroke, manifolds and year-specific accessories must be matched to the actual engine.
Notable Applications
International Scout 80International Scout 800International light trucks in selected applications
Strengths
- Simple durable construction
- Strong low-speed torque for displacement
- Good Scout originality value
Weaknesses / Watch-outs
- Modest highway power
- Heavy for a four-cylinder
- Carburetor and ignition condition strongly affect drivability
Common Upgrades
- Electronic ignition
- Carburetor rebuild
- Exhaust improvements
Racing History & Legacy
The 4-152 was designed for low-speed utility and off-road work rather than a dedicated factory racing program. Its importance in competition is mainly as the original Scout powerplant in an early American compact 4x4 platform.
The 152 was the original Scout powerplant and established the mechanical personality of early International compact 4x4s. Its architecture also led directly to the larger 196 four-cylinder.
References & Image Credit
IH Scout engine specification document
technical reference
International Harvester operator manual — C152/C196/C304/C345/C392/C446/C549/C605
manufacturer service manual
MotorTrend — 1963 Scout 4-152 specifications and engine-development history
historical reference
IH Scout engine specification document
technical reference
International Harvester operator manual — C152/C196/C304/C345/C392/C446/C549/C605
manufacturer service manual
MotorTrend — International Scout engine-development history
historical reference
Key Factory / Build Variants
152-T turbo
1965–1967/68Application/year dependent
Rare factory turbocharged Scout four-cylinder
Engineering Notes Worth Knowing
01
3.875 x 3.21875-inch bore and stroke; 152 cu in / 2.5 L.
02
Pushrod OHV inline/slanted four with cast-iron block and head.
03
Documented later Scout output: 93 hp at 4,400 rpm and 143 lb-ft at 2,400 rpm.
04
Primary applications included Scout 80 and Scout 800; a turbocharged 152-T was also offered.
History · context · related reading
The Story Behind International Harvester 4-152 Comanche
International launched the Scout with an engine that felt more like farm-and-truck machinery than a passenger-car four-cylinder. The 152 gave the compact Scout a deliberate low-speed character and ruggedness that matched the vehicle’s utility mission.
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