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EC 263R 4-Cycle Racing Engine Bottom End Kit without Tank Mounts
Complete Exploded View of the EC 263R Short block
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EC 263R 4-Cycle Racing Engine Bottom End Kit without Tank Mounts

Part Number: 263R-KIT
Online Price: $659.99
EC's Tillotson 263cc/16ci Short Block Kit
Availability: Out of Stock.


We are introducing the NEW! EC 263R Bottom-End Kit for racing go-karts and mini bikes. 

After many years of getting the right components together, you'll be able to assemble a low-buck 3-inch motor with a 58mm stroke crankshaft to build a 263cc or 16ci engine. During the development of the Tillotson R-Series Block, EC considered improvements and alterations to get a 76mm or 2.99" bore to best fit in the block. 

Some changes include removing the upper dowel holes and adding material around the jug, including the push rod galley, which increased the gasket surface area for a better gasket seal. 

When the Tillotson blocks were introduced, EC had a 76mm bore block made without the sleeve. However, changes in production meant Tillotson could no longer sell that version of the block. Instead, EC is boring and sleeving the 70 & 72mm blocks. 

Part of EC's goal of a 263cc engine was to design a 76mm piston similar to the one they designed for the Tillotson 72mm bore block. They made a lightweight and affordable 76mm piston and a new rod slightly longer than the rod used in the 236R kits. The piston is significant in making the package less expensive. 

Our kit includes a partial short block allowing you to add your current clone or predator parts, racing carburetors, and other components. If you want to build a brand new engine, we have many add-ons to make a complete engine. The Short Block does not come assembled.

76mm Tillotson Reinforced Block without Tank Mounts - This is the engine's core and allows most of the magic to happen. We designed these blocks to handle mild endurance racing engines for Tillotson's 225RS/T4 Class. We made the block thicker and more robust to reduce flex and distortion; this prevents power loss through crank flex and blow-by between the piston and cylinder. A 76mm bore is one of the largest bores possible in a factory block. 

EC 76mm Lightweight Hypereutectic Piston - The piston is superior in performance and longevity over stock Chinese cast pistons used in other engines and kits. The piston uses the latest technology and design, utilizing a racing slipper skirt vs. a conventional barrel skirt design of other stock pistons. This piston uses an aluminum alloy with high silicon for a lower thermal expansion coefficient, allowing tighter tolerance. The low slipper skirt design also allows more clearance in the rotating assembly for larger stroke crankshafts. We also made the compression height shorter by moving the pin's location and using a smaller diameter wrist pin. These improvements allowed the use of a longer rod while reducing weight in the rotating assembly.

58mm(2.283") Stock Stroker Crankshaft - This is the first-ever 58mm stock crank for the clone market. The crankshaft is significant because it has only .017" less stroke than the billet cranks made in the aftermarket and, more importantly, at less than a quarter of the price. With our kit, you will build an entire short block for just the billet crank alone. The Taper will fit any Honda-Clone flywheel(will not fit Predator 212 Flywheels)

EC 8282 Forged Rod - Our new EC Forged Rods are designed to allow more stroke with standard clone journal crankshafts and bigger camshafts. The 8282 rod is explicitly made for this kit. It is 3.475 inches and brings the piston up to zero deck. This rod is made in-house and is unique to our engine combination. 

These components are the core of the 266R "U-Build-It" Kit. It comes with the hardware gaskets to build a complete short block minus the camshaft. 

Kit Includes:

- Tillotson 76mm Reinforced Block with Tank Mounts

- Tillotson 76mmLightweight Hypereutectic Piston

- EC 8282 Billet Connecting Rod

- 58mm Stroker Crankshaft(EC Exclusive)

- Stock Sidecover

- All hardware and gaskets included assembling the short block.

- Stock Tappets

- Push Rods are not included(Chromoly Recommended for all builds)

To Build a Complete Engine, we have many add-ons to build combinations based on your budget and goals.

The 263R Engine Kit is considered a racing product, and the final assembly is the builder's responsibility. We do not offer any warranty for this engine package. 


Does the kit require any machining or clearance-ing?
The cylinder has been sleeved, bored, and honed for assembly. 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 263R?
No. The 263R can be completed with a variety of 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 263R or other engines?
We do not sell a complete version of the 263R and do not do one-off engine builds. We do a few inventory engines available on our website, such as the 228R and variations of the 223 Wildcat and 236R engines. 

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 16ci, making 16hp 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 16ci that 32hp, and considered a very extreme build that very few can achieve. Modern Pro Stocks are around 2.5hp per cube. At 16ci, that's 40hp and impossible for an air-cooled, power equipment engine with limited technology and development.

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