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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: $399.99
EC's Tillotson 236cc/14.41ci Short Block Kit
Availability: Out of Stock.


The NEW! EC 236R Racing Engine Stage 3 Kit is designed to build your kart or mini bike racing engine. 

We thought of what it would take to handle a 14.5ci Open Modified from the beginning of our development on the Tillotson Engine Program. Our new 236R is 236.15cc, or 14.41ci puts you very close to the mark and does it while being extremely budget-friendly. 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. Engine and Short Block do not come assembled.

72mm Tillotson Reinforced Block - 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. At 72mm bore, it is one of the largest bore blocks straight from the factory. Still, with our background in modifieds, we couldn't pass the opportunity to build one of the best blocks for high horsepower applications. 

Tillotson Racing Lightweight Hypereutectic Piston - This piston is advertised as a forged piston by other distributors; it is, in fact, not a forged 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.

EC Forged Rod - EC Carburetors designed the original billet rod for Tillotson 225RS engines, using a 55mm stroke crankshaft. And we built the first billet rod to fit the Tillotson piston and a 56mm crank and are now the first to use our exclusive 58mm crankshaft. Our new EC Forged Rods are designed to allow more stroke with standard clone journal crankshafts and bigger camshafts. This rod is made in-house and is unique for our engine combination.

These components are the core of the 236R "U-Build-It" Kit. It comes with the hardware gaskets to build a complete short block minus the camshaft. 

Kit Includes:

- Tillotson 72mm Reinforced Block

- Tillotson 72mmLightweight Hypereutectic Piston

- EC Billet Connecting Rod

- 58mm Stroker Crankshaft(EC Exclusive)

- Stock Sidecover

- All hardware and gaskets included assembling the short block.

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

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

Cylinder Heads:

Stock 212R Cylinder Head 

- Stock 27mm Intake/25mm Exhaust 5mm Stem

- Stock Rocker Assembly w/Stock Springs

Approximate Compression Ratio: 

- 9.8:1 with Stock Head Gasket 

- 10.27:1 with EC Copper Head Gasket

RX2725 Stainless Steel 27/25 Tillotson Head - EC Carburetors is continuously looking to improve the Tillotson and Clone Engine Market's performance. We introduce the first 5mm stainless steel valves for the Tillotson 212/225 and Predator Non-Hemi Heads. The stronger valves make running higher spring pressure and more aggressive camshafts easy without the fear of valve failure. The stainless steel valves also save on valve train weight, allowing less spring pressure to turn more RPMs. 

- Stainless Steel 27mm Intake/25mm Exhaust 5mm Stem

- No Rocker Assembly or Springs

Approximate Compression Ratio: 

- 9.8:1 with Stock Head Gasket 

- 10.27:1 with EC Copper Head Gasket

TILBV-18 Tillotson - Our Tillotson Big Valve Head is for more flow and a slight gain in compression. The heads do not come ported; we do this to allow you to match it to your combination.

- Stainless Steel 32mm Intake/28mm Exhaust 5.5mm Stem

- No Rocker Assembly or Springs

Approximate Compression Ratio:

- 11.32:1 with Stock Head Gasket 

- 11.97:1 with EC Copper Head Gasket

14cc High Compression Head - One of the most popular heads for modified applications. Compression is a great way to build power, especially with smaller displacement engines like the 196 clone, Honda GX200, and Predator. But we warn you with the 236R's extra displacement, you will see significant gains in compression. The added compression may be too much to pull start and require higher octane race gas or better methanol.

- Stainless Steel 32mm Intake/28mm Exhaust 5.5mm Stem

- No Rocker Assembly or Springs

Approximate Compression Ratio:

- 13.59:1 with Stock Head Gasket 

- 14.56:1 with EC Copper Head Gasket

Heads do not Include Head Bolts, Valve Covers, Valve Cover Gaskets, Rocker Assembly or Carburetor, and Exhaust Hardware. These Items are Sold Separately

Head Gaskets:

Stock 72mm Tillotson .045" Head Gasket - This is suitable for most builds.

EC 72mm Copper Head Gasket - Built to the same architecture as the Tillotson Head Gasket, including the added area between the pushrods and the bore. This gasket is thinner and will raise the compression, and it offers a good seal for racing engines. 


Tillotson PK-1B - We designed the PK-1B to be the best performing .615 factory carburetor. It's so a good many tracks, and organizations have outlawed them even though they can pass tech. 

.658 Stock Appearing Gas - This is our first level SA-appearing carburetor. The bored carburetor is an excellent upgrade where you must run a stock-style carburetor and have a small budget.

.680 Stock Appearing Gas - The Tillotson PK carburetors are the easiest carburetors to bore to larger sizes. The .680 is usually the maximum bore for most kart shops and engine builders can build. We created this size carburetor to compete at those sizes, but if you want to see the "Twilight Zone," like Ol' EC would say, you need our PK-875 Carburetors.

PK-875G Stock Appearing Gas - We've built the best flowing stock appearing on the market flowing in the range of 74cfm. We've found it around 5-10% better than the next closest claim. You're getting over 40 years of carburetor excellence and innovation regardless of the flow.

PK-875A Stock Appearing Methanol - Like the PK-875, this one is set up for Alcohol(Methanol). Many have struggled to make power on the high end with such a small carburetor. While so many focused on airflow, we ensured we could deliver the fuel to produce power. 

Tillotson HL-304WXBP-19K Gas - This is our blueprinted HL-304WXG carburetor kit. The Blueprinted carburetor focus on matching fuel ratios for power to still over excellent performance over stock carburetors and many slide carburetors of the same size. Unlike the Dominator that is meticulously built for improved flow and performance, the blueprinted model offers a great alternative to the Dominator's cost. 

Tillotson HL-304WX-19K Gas - Our Dominators are dyno tested and track proved. These carburetors were developed during some of the better years of karting. When winning at places like Daytona meant you were the baddest SOB around. Our dominators continue to live up to the legacy of "dominance" with unmatched success and performance. 

Tillotson HL-304WXBP-10K Methanol - Just like the HL-304WXBP-19, this is for the ones wanting to run methanol. As many know, methanol can make any engine more powerful with the proper tune. What makes it even more significant in reducing the engine temperatures of our air-cooled industrial engines. 

Tillotson HL-304WX-10K Methanol - Like the other Dominator, this one runs on methanol. Running methanol requires around twice the volume of gasoline to make that extra power. After each race, you will need to flush your fuel system and change your oil after each practice round, heat, and feature. 

X360 EC Intimidator Methanol - Our Intimidator Series allowed us to offer EC's Stage 3 Carburetors at a lower price. By building our carburetor bodies, plates, and needles to reduce our labor-intensive builds. This carburetor is not only a little larger than the HL-304 but has our signature three-piece shaft that has been imitated by the carburetor manufacturers and attempted by our competitors. Often copied but never duplicated. 

X380 EC Intimidator Methanol - Our X380 is our winningest Open carburetor to date. The X380 has won almost every big race from the Big O to Thanksgiving Thunder for the last 4-5 years. Whether it's been on a flathead or OHV engine, this carburetor is highly recommended for ported big valve heads or even most billet heads. 


Mod2 - The Mod2 is one of the most popular camshafts to upgrade due to its easy installation and moderate performance increase. This cam has stock lift numbers but added duration to move peak torque higher in the powerband. This camshaft is often used in mod stock classes or as a cheater cam. It also works well on more recreational hot rod builds. 

Use 18-22lbs springs

Banzai 265 - The Banzai was developed to be an out step up from the mods with fewer restrictions on the lift. This cam's effectiveness became the cam also used in the Tillotson 225RS because its low-speed responsiveness is well suited for T4 and other 4-cycle sprint racing. 

Use 22-26lbs Springs

EC's Tennessee Thunder Stick 698 - The Cam compares to many 275 cams like the Dyno 275-CL or Isky Black Mamba, which are very popular size camshafts used on higher performance recreational hot rods mildly modified racing engines. This camshaft will pair well with stock-size valves and smaller carburetors. This cam may require some clearance to fit. Use 26lbs or higher Springs

EC's Tennessee Thunder Stick 787 - This camshaft is typically designed for limited, modified OHV engines but has been very useful in stock appearing engines as well. The 787 grind is an excellent all-around cam that can be successful with most combinations of heads and carburetors. This camshaft would work well in the high-flowing head by adding a little ratio to the rockers. This cam may require some clearance to fit. Use 32lbs or higher Springs

EC's Tennessee Thunder Stick 904 - The 904 grind is the big cam for those with an excellent flowing head, the usual ones with big valves. Some prefer this cam with 1.1 rockers versus a smaller cam with 1.2 or 1.3 rockers. This cam may require some clearance to fit. Use 32lbs or higher Springs

Choose the Springs to fit your application best. Valve Springs range from 22-36lbs and come with 5mm or 5.5mm retainers. If you order a cylinder head from us, be sure you order the correct springs and retainers. 

We recommend upgrading our billet side cover if you're building to the higher echelon of horsepower. The billet side cover will help stabilize the crankshaft and further stiffen the block.

You can choose from our different color blower housings and recoils. Adding the blower housing will also come with the kill switch. 

We hope you enjoy your new racing engine. You can ask questions on this page or call or email us if you need help piecing together your combination.

The 236R 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?
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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