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EC 236R 4-Cycle Racing Engine Bottom End Kit
Complete Exploded View of the EC 236R Short block
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EC 236R 4-Cycle Racing Engine Bottom End Kit

Part Number: 236R-KIT
1 Review(s)
Online Price: $439.99
EC's Tillotson 236cc/14.41ci Short Block Kit
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Description

EC 236R Racing Engine Kit – U-Build-It Short Block for Karting & Mini Bike Racing


Build a true high-displacement, high-performance racing engine with the EC 236R Racing Engine Kit—the same foundation we engineered for our proven Tillotson engine program. Designed to support 14.5ci Open Modified class builds, this kit takes your engine to 236.15cc (14.41ci)—right on the edge of class-max displacement, all while staying budget-friendly.


This kit includes an unassembled short block that integrates with many of your existing Predator or Clone components, such as heads, carburetors, cams, and flywheels. Whether you're upgrading an existing engine or starting fresh, we also offer add-ons to turn this into a full race-ready package.
Note: Engine and short block are not pre-assembled.


What’s Included in the EC 236R Short Block Kit?

  • Tillotson 72mm Reinforced Block
  • Tillotson 72mm Lightweight Hypereutectic Racing Piston
  • EC 3.415” Billet Connecting Rod (Part #8279)
  • 58mm (2.283") Stroker Crankshaft
  • OEM Side Cover
  • All Hardware and Gaskets for Short Block Assembly
    - Head gasket not included — copper and fire-ring gaskets sold separately
    - Pushrods not included — we recommend Chromoly pushrods for all builds


Key Features & Engineering Advantages:

  • 72mm Reinforced Tillotson Racing Block

This is the heart of the 236R engine. Originally developed for Tillotson’s endurance T4 and 225RS class engines, this block is thicker, more rigid, and resists crankshaft flex and cylinder distortion, helping prevent blow-by and power loss. Its factory 72mm bore offers one of the largest displacement capacities available in a clone-class engine block.

  • 58mm Stroker Crankshaft – Budget-Friendly Power

This is the first 58mm stock-style crankshaft available in the clone market. With only 0.017” less stroke than billet aftermarket cranks—and a fraction of the cost—it allows builders to achieve maximum displacement without blowing their budget.

  • Tillotson Lightweight Hypereutectic Piston

Often incorrectly advertised as forged, this piston uses a high-silicon alloy with advanced slipper skirt geometry for low thermal expansion and reduced rotating mass. The shorter compression height and smaller wrist pin diameter allow for a longer rod, improving rod ratio and reducing piston speed.

  • EC Forged Connecting Rod – Built for the 58mm Crank

Custom-designed for our 236R setup, this in-house forged rod is built to handle the increased stroke and rotating forces of our 58mm crank while maintaining compatibility with standard Clone journals. Built for high-RPM endurance and drag racing applications.


Recommended Upgrades for Max Performance:

  • Billet Side Cover – Stabilizes the crank and stiffens the case under high horsepower.
  • Chromoly Pushrods – Stronger and more heat-resistant for aggressive cam profiles.
  • Copper/Fire-Ring Head Gaskets – For better sealing under high compression.
  • Performance Cams & Heads – Optional EC packages available for your goals.


Important Notes:

  • This is a racing engine kit intended for experienced builders.
  • Final assembly and tuning are the responsibility of the builder.
  • No warranty is provided due to the nature of racing applications.


Build your next winning engine on a proven platform. The EC 236R Stage 3 Kit gives you the foundation, flexibility, and reliability to race with confidence—all while staying within budget.

FAQ

Does the kit require any machining or clearance-ing?
Components included in the kit do not need any additional machining or clearance-ing. However, some camshafts may need clearance-ing for the compression release or lobes. If running a copper head gasket, it's recommended to have the cylinder head o-ringed for adequate cylinder sealing.

Do you assemble the 236R?
No. The 236R can be completed with various camshafts, flywheels, and cylinder heads that may require additional clearancing. If the engine came assembled, it would need to be disassembled to make these adjustments. By selling a kit, it keeps the cost down for experienced engine builders to finish the build. 

Do you build complete 236R or other engines?
Yes, we build two levels of the 236R available on our website, but we do not do custom or one-off builds.

How much horsepower can this kit make?
Any horsepower advertised without SAE or similar certification is unreliable and generally false. But for reference, high-performance factory hot rods in the 60's/70's would make about 1hp per cubic inch. At 14.41ci, making 14.1hp is by no means a mild engine. Pro Stocks(most advanced and powerful natural aspirated pushrod engines) of the same era would make 2hp per cube, at 14.41ci that 28.82hp, and considered a very extreme build that very few can achieve. Modern Pro Stocks are around 2.5hp per cube. At 14.41ci, that's 36hp and impossible for an air-cooled, power equipment engine with limited technology and development.

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Customer Reviews

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These guys and gals are good answered every question I ask them seems to me they like there job and take care of business WoW that's hard to find nowadays .
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Reviewed by:  from Houston tx on 5/25/2023
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