BLDB Launches SEMTO “ST-NF2/FS-L200AC” 7cc Inline 2-Cylinder 4-Stroke Engine Assembly Kit

Gadgets

Reason for the New Product

Engine models typically fall into two categories: display models that replicate external appearance and functional models that operate using fuel and ignition. The SEMTO ST-NF2/FS-L200AC is a functional model, designed to provide an experience encompassing assembly, fuel preparation, starting, and adjustment. BLDB has expanded its range of metal mechanical models by adding this inline 2-cylinder functional engine, offering a different layout from previous V-type engines. This new product provides an option for observing the crank mechanism and valve drive from the component arrangement, appealing to those who wish to document the entire process of a machine coming to life, beyond just displaying a finished product.

Structure of the Inline 2-Cylinder 4-Stroke SOHC

The ST-NF2/FS-L200AC is an inline 2-cylinder engine with a total displacement of 7cc. Each cylinder has a displacement of 3.5cc, featuring a long-stroke design with a bore of 16.6mm and a stroke of 17.0mm. It is a 4-stroke SOHC engine. The assembly process allows users to observe the reciprocating motion of the pistons, the linkage of connecting rods and crankshaft, and the valve mechanism controlling intake and exhaust. The approximate rotational speed ranges from 4,000 to 16,000 rpm, with a nominal output of 0.6 PS. The performance of this product is not solely judged by numerical values, as the assembly sequence, tightening, lubrication, fuel supply, and pre-start inspection all influence its operation.

SOHC Type Engine

Power Transmission with Dual Timing Belts

This product utilizes two timing belts for power transmission. Timing belts transfer rotation from the crankshaft to the valve mechanism, requiring careful attention to installation direction and tension. The product description indicates a design to prevent tooth skipping at high RPMs. During assembly, it is important to check the belt position, tooth engagement, and interference during rotation, avoiding excessive force for adjustment. As the engine is assembled with internal components visible, users can observe how the belts and pulleys transmit rotation.

Engine with Gears and Fan

Electric Starter by 480 Brush Motor

The engine is started using a 480 brush motor electric starter. The recommended starting power source is a 7.4V 2S lithium battery. A type F 4-stroke glow plug is used, and a compatible ignition module is required. The inclusion of components such as the starter, ignition module, glow plug, battery, and fuel tank varies depending on the selected product variation. Customers should check the differences between “Engine Model,” “Engine Model + Engine Starting Kit,” and “Engine Model + Engine Starting Kit + Base” on the product page before ordering.

Kit Components

Air Cooling and Mixed Lubrication

The cooling system is air-cooled, eliminating the need for a water-cooling radiator or pump. However, during operation, it is essential to choose a well-ventilated location to prevent heat accumulation. The lubrication method is mixed lubrication. Users must adhere to the provided instructions and manufacturer’s specifications regarding fuel and oil types, mixing ratio, and usage volume. The engine is not compatible with gasoline. Using non-specified fuels may lead to starting failures or component damage.

Engine on Stand with Components

CNC Machined Aluminum Alloy with Anodized Finish

Key components are made from CNC machined aluminum alloy and finished with anodizing. The main unit measures approximately 112 x 90 x 92mm and weighs about 535g. Its compact size makes it suitable for placement on a workbench or model shelf, but sufficient space for fuel, exhaust, and rotating parts is required during operation. When displaying, it is advisable to choose a stable base to secure the engine and prevent falling or tipping.

Compact Engine

Three Options Tailored to the Assembler

The required contents for the engine model vary depending on how much preparation an individual wishes to undertake. For those primarily interested in assembling the engine itself, the “Engine Model” option is available. If a user wishes to confirm all basic parts necessary for starting, the “Engine Model + Engine Starting Kit” is recommended. For those who want to set up a display environment including a base, the “Engine Model + Engine Starting Kit + Base” option is offered. Prices, stock, and included accessories for each variation are based on the official product page at the time of purchase.

Kit Components in Tray

Choosing from the Metal Engine Model Series

The “Metal Engine Model” collection on the BLDB official online store features a range of models, including inline 2-cylinder, V-type engines, and various power mechanisms. Customers can compare and select models based on cylinder count, engine type, fuel system, cooling method, starting method, and whether it is a finished product or an assembly kit. The choice between a large displacement V8 or starting with a small inline 2-cylinder depends on the workspace, experience, and operating environment. The SEMTO ST-NF2/FS-L200AC offers a new option for those interested in a 7cc inline 2-cylinder engine with an air-cooled structure.

Series List:
https://bldb.jp/collections/engine-models

Engine on Wooden Base

Product Specifications

Item Specification
Brand SEMTO ENGINE
Model ST-NF2／FS-L200AC
Type Inline 2-cylinder, 4-stroke, SOHC
Total Displacement 7cc (3.5cc × 2)
Bore 16.6mm
Stroke 17.0mm
Rotational Speed 4,000～16,000rpm
Nominal Output 0.6PS
Cooling Method Air cooling
Lubrication Method Mixed lubrication
Starting Method Electric start by 480 brush motor
Carburetor Single carburetor
Fuel Used Methanol-based glow fuel with 20-25% nitromethane
Recommended Starting Power 7.4V (2S) Lithium battery
Body Size Approx. 112×90×92mm
Body Weight Approx. 535g
Recommended Age 14 years and older (minors must use under supervision of guardian or experienced person)

Safety Precautions Before Use

This product is a functional engine that operates by burning fuel and is not a toy. Do not start the engine in poorly ventilated indoor areas. Store fuel away from fire and high-temperature areas, and secure the engine firmly on a stable stand during operation. Exercise extreme caution when handling rotating parts, hot parts, exhaust, and fuel, and wearing protective eyewear is recommended. When minors use the product, a guardian or experienced person must supervise the assembly and operation. When installing the engine in RC cars, RC boats, or custom models, adjustments to the mounting base, cooling, exhaust, and fuel system are necessary. Compatibility with all vehicle chassis is not guaranteed.

Product Information

About BLDB

BLDB (Building Block) offers 3D metal puzzles, mechanical models, and power models assembled from metal parts through its official online store. The company aims to provide engaging hobby time, from preparation before assembly to component management during work and display after completion. Product specifications, target ages, stock, and delivery conditions vary by model, so please check each product page before purchasing.

SNS

Company Profile

  • Overseas Expansion Lead: SHUEI NETWORK TRADING CO., LTD.

  • Business Activities: Sales of 3D metal models, mechanical puzzles, and DIY assembly kits.

  • Inquiries: Please contact via the inquiry form on the official online store.

Copied title and URL