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M45 Stage 2 EJ25 Closed Deck Short Block for WRX, STI, Legacy GT, Forester XT

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M45 Stage 2 EJ25 Closed Deck Short Block for WRX, STI, Legacy GT, Forester XT

M45 Stage 2 EJ25 Closed Deck Short Block for WRX, STI, Legacy GT, Forester XT


M45 Automotive Subaru EJ25 Complete Closed Deck Short Block

At the core of our engine-building program, we are fully dedicated to doing our best and protecting our reputation. We use only the highest-quality components and specialized machining and assembly techniques, ensuring they perform well and last long. Our goal is to create top-notch engines that exceed expectations and last for a long time.

This closed-deck short block is designed to ensure the longevity of your vehicle's performance and to handle higher horsepower and torque levels, that typically distort or crack open-deck blocks. The engine case, composed of new Subaru OEM case halves are modified to accommodate the Closed Deck inserts, effectively turning the block into a sturdy deck. It has been subjected to a thorough Bore and Deck process. This includes precision boring and honing of the case halves, ensuring perfect fitment and alignment. A torque plate is utilized during the honing process to enhance the precision further, resulting in a flawless engine case that guarantees optimal performance. Central to the design of this short block is a OEM Subaru Nitrided Crank.

The engine boasts a premium Wiseco Subaru EJ257 WRX/STI 99.75 forged piston kit. Forged pistons, known for their exceptional strength and wear resistance, add significant value to the engine's performance and overall durability. If it's modified for more power, the stock pistons may not be able to withstand the increased stress. This is where forged pistons come in. We have also equipped the engine with high-grade piston rings and seals, improving the engine's compression and oil control. This not only amplifies the engine's efficiency but also bolsters its long-term durability.

The Stage 2 Closed Deck Engine also incorporates new H-beam forged connecting rods that have been carefully machined to ensure seamless fitment. Complementing these are King or ACL Hardened Rod Bearings and Main Bearings, crucial components that endure high-stress conditions and minimize wear, thereby extending the engine's lifespan.

In addition, this package comes with wrist pin and cover seals at no extra cost. These crucial components play a vital role in the engine's operation.


At this time we only offer in-store pick up. We are working on a solution for shipping and hope to have it implemented in the near future.


M45 Automotive's 24 Months or 24,000 Miles Warranty

Starting Line: The moment your engine arrives at your door, your warranty comes alive. 

Only Yours: This warranty is a special agreement just for you, the original engine purchaser, and can't be passed on.

Coverage: Short block / long block components that we at M45 Automotive have assembled are under our warranty's protection.

Manufacturer's Assurance: Each part that we use in our assembly comes with its own manufacturer warranty. However, we can't extend coverage to any components you supply.

Limitations: Our warranty doesn't cover other parts of the engine, turbochargers, accessories, or your vehicle. Any damage to your vehicle resulting from an engine failure isn't covered either.

Work & Parts: Labor costs for reassembly and extra parts like gaskets or fluids needed for reinstallation aren't included in our warranty.

Shipping Info: If you need to return a product, the shipping's on you. Also, in cases where a warranty claim is rejected, you'll need to cover return shipping.

Your Move: If you need to make a warranty claim, reach out to us directly. But remember, if a claim is deemed invalid, the cost of engine teardown is on you.

Maintenance Matters: Keeping your engine well-maintained is crucial. You'll need to provide proof of this maintenance as part of the warranty process.

Fixed Term: Any repairs or replacements covered under the warranty won't extend its period. The duration remains as initially stated.


M45 Automotive's Conditions of Warranty 

This warranty covers the entire product you purchase from us at M45 Automotive. However, there are a few exceptions where the warranty does not apply:

Proper Break-In: The warranty will not cover the engine if the proper break-in period isn't followed. This initial period is crucial for your engine's longevity.

Proper Tuning: The warranty won't cover issues arising from an engine that isn't properly tuned. Adequate tuning is crucial for optimal engine performance.

Preventable Damage: The warranty won't cover damage resulting from overheating, lack of lubrication, or contamination. To keep your engine in top shape, regular maintenance is crucial.

Accidents or Misuse: If repairs or replacements are needed due to accidents or misuse, our warranty can't cover it. We want you to enjoy your engine, but please handle it with care.

Racing and Competition: If the engine gets damaged from racing, competition, or any use beyond its original design, the warranty won't cover it.

Unauthorized Servicing: If anyone other than M45 Automotive repairs or services the engine without our written authorization, the warranty won't cover it. We trust our team to give you the best service!

Certain Types of Damage: Damages from detonation, pre-ignition, faulty electrical or computer components, turbo components, or fuel-related components aren't covered by our warranty.

Consumables: Items like oil, anti-freeze, filters, spark plugs, and other consumables aren't covered. Regular replacement of these items is a part of maintaining your engine.

Non-Related Diagnostics: Our warranty doesn't cover the diagnostic time for issues not related to the parts and services we provide. If it's not about our parts or services, it's out of our hands.

Modifications: If you modify the engine, including alterations like camshafts, the warranty can't cover it. We want you to enjoy our engines as they are.

We're here to ensure your M45 Automotive experience is a positive one, so don't hesitate to get in touch if you have any questions or concerns.

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Need help? We're available at(530) 823-7645 - Email us
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