LYCOMING 05K21112 Cylinder Deck Hour Iran Kit 4X
fits model: Io-360, Io-720.
( Brand: Lycoming ), ( Manufacturer Part Number: 05K21112 ), ( Part Type: Cylinder Deck )
Review LYCOMING 4x Cylinder Kit Narrow Deck Hour Iran fits IO-360 IO-720
The **Lycoming 05K21112 4-Cylinder Kit** is a meticulously engineered rebuild kit designed specifically for Lycoming s iconic **IO-360** and **IO-720** series engines, ensuring peak performance and longevity for aircraft owners and mechanics alike. This high-quality kit is tailored for the **deck-houred** engine, meaning it has been carefully selected to accommodate the wear and mileage of an engine that has seen substantial operational hours, often found in older but well-maintained general aviation aircraft. The kit includes a complete set of **precision-machined cylinder assemblies**, featuring **4x high-performance cylinders** with reinforced heads, optimized for smooth combustion and enhanced durability. Each cylinder is paired with a **new piston and ring set**, featuring Lycoming s proprietary **forged aluminum pistons** with hardened tops and a carefully engineered ring pack including a top compression ring, oil control rings, and a scraper ring to minimize friction, reduce oil consumption, and maintain optimal compression ratios. The kit also incorporates **new valve springs, retainers, and rocker arms**, ensuring proper valve train function and preventing premature wear or failure, which is critical for engines operating at high deck hours. Additionally, the **cylinder-to-block gaskets** are included, designed to provide a secure, leak-free seal that resists heat and pressure fluctuations, a common challenge in older engines. This kit is ideal for mechanics performing **major overhauls** or **deck-hour rebuilds**, as it restores the engine s structural integrity while incorporating modern materials and tolerances to improve efficiency and reliability. Whether installed in a classic Cessna 172, a Piper Cherokee, or a Beechcraft Bonanza, the **05K21112 kit** ensures that the IO-360 or IO-720 engine will operate with renewed vigor, extending its service life and maintaining the aircraft s airworthiness with minimal risk of catastrophic failure. Proper installation by a certified Lycoming technician is recommended to maximize performance and adhere to FAA regulations.
### **Pros and Cons of Buying a Lycoming IO-360/IO-720 Engine with a 4-Cylinder Kit (e.g., 05K21112, Deck Hour, Iran-Sourced)**
#### **Pros**
1. **Cost-Effective Replacement or Upgrade**
- A Lycoming IO-360/IO-720 engine kit (especially from Iran or other secondary markets) is significantly cheaper than a new or even a fully rebuilt OEM engine. This makes it an attractive option for budget-conscious aircraft owners, restorers, or operators with older aircraft.
2. **Availability of Parts and Customization**
- The IO-360/IO-720 is a widely used engine in general aviation, meaning parts (crankshafts, pistons, valves, etc.) are relatively accessible, even if some components may require sourcing from secondary markets.
- Some kits allow for modifications (e.g., increased compression, fuel injection upgrades) that can improve performance or fuel efficiency.
3. **Potential for Restoration Projects**
- For aircraft owners working on a restoration, a used or kit-built IO-360/IO-720 can be a practical choice if the aircraft was originally equipped with this engine or a similar model. This avoids the need for major airframe modifications.
4. **Lower Initial Investment**
- Compared to a brand-new Lycoming engine (which can cost tens of thousands of dollars), a kit or used engine from Iran or other markets can reduce upfront costs by 50% or more. This is particularly useful for hobbyists, students, or operators with limited funding.
5. **Compatibility with Older Aircraft**
- Many light aircraft (e.g., Cessna 172, 182, Piper Cherokee, etc.) were originally designed with IO-360 or IO-720 engines. A kit-built or refurbished version can fit seamlessly into these airframes without requiring major modifications.
6. **Potential for DIY Assembly**
- Some buyers with mechanical experience may prefer assembling the engine themselves, saving on labor costs. This can be appealing for those who enjoy hands-on work or have access to skilled mechanics.
---
#### **Cons**
1. **Uncertainty Over Build Quality and Reliability**
- Engines sourced from Iran or secondary markets may have inconsistent build quality, especially if they are not fully inspected or tested before sale. There is a risk of hidden defects, poor machining, or substandard materials that could lead to premature failure.
- Without proper documentation (e.g., FAA-approved rebuild records, stress analysis, or test runs), the engine s safety and longevity cannot be guaranteed.
2. **Lack of FAA or Regulatory Approval**
- Most Lycoming engines sold in the U.S. must comply with FAA regulations, including stress analysis, test runs, and documentation. Engines from Iran or unapproved sources may not meet these standards, making them difficult to legally install or operate in the U.S. (or other countries with strict aviation authorities).
- Installing an unapproved engine could result in FAA violations, insurance issues, or grounding of the aircraft.
3. **Maintenance and Support Challenges**
- Without proper documentation or FAA approval, finding authorized mechanics or parts dealers for these engines can be difficult. Standard Lycoming service centers may refuse to work on them, forcing the owner to rely on independent or less experienced technicians.
- Warranties (if any) may be void or unenforceable, leaving the owner responsible for all repair costs.
4. **Risk of Performance and Safety Issues**
- Engines built from kits or sourced from unregulated markets may not meet the same performance or safety standards as factory-built or FAA-approved engines. This could lead to:
- Reduced power output or efficiency.
- Higher risk of catastrophic failure due to poor materials or assembly.
- Difficulty in obtaining insurance coverage for the aircraft.
5. **Legal and Compliance Risks**
- In the U.S., installing an unapproved engine may violate FAA regulations under **14 CFR Part 43 (Maintenance, Preventive Maintenance, Rebuilding, and Alterations)** and **Part 91 (General Operating and Flight Rules)**. This could result in:
- Fines or penalties from the FAA.
- Denial of aircraft registration or airworthiness certificates.
- Difficulty in obtaining insurance or financing for the aircraft.
6. **Resale and Depreciation Concerns**
- Aircraft with non-standard or unapproved engines are harder to sell. Buyers typically prefer FAA-approved engines, which can significantly reduce the resale value of the aircraft.
- The engine s lack of documentation may also deter potential buyers, making it a long-term liability rather than an asset.
7. **Potential for Import Restrictions**
- Engines sourced from Iran or other restricted countries may face import bans, customs issues, or additional scrutiny by aviation authorities. Shipping and compliance costs could further increase the total expense.
8. **Lack of Long-Term Data**
- Since these engines are not widely used in approved applications, there is little real-world data on their long-term reliability, failure rates, or maintenance requirements. This makes it difficult to predict how they will perform over time.
---
### **Conclusion**
Buying a Lycoming IO-360/IO-720 engine kit (especially from Iran or unapproved sources) can be a **cost-effective solution for budget-conscious buyers**, particularly for restoration projects or aircraft where the engine is already non-standard. However, the **risks of unapproved build quality, legal compliance issues, and safety concerns far outweigh the benefits** for most operators.
For most aircraft owners, **purchasing an FAA-approved, stress-analyzed, and documented Lycoming engine** (even if more expensive) is the **safer, more reliable, and legally compliant choice**. The potential savings from a kit-built engine may not justify the risks of non-compliance, insurance problems, or safety hazards.
If you are considering this path, **consult an FAA-designated mechanic or aviation attorney** to assess the legal and technical implications before proceeding. Alternatively, explore **rebuilt or used Lycoming engines from reputable dealers** to ensure compliance and reliability.
### **Recommendation**
- **Do not install an unapproved or non-documented Lycoming engine** in an aircraft intended for flight in the U.S. or other regulated airspace.
- **Opt for an FAA-approved, stress-analyzed, and documented engine** from a licensed Lycoming dealer or rebuild facility.
- If working on a restoration project, **verify the engine s compliance with local aviation authorities** before installation.
- For budget constraints, consider **alternative options** such as:- Purchasing a **used, FAA-approved engine** from a trusted seller.
- Exploring **fuel-efficient or alternative powerplant options** (e.g., turboprop conversions, electric hybrids) if cost is a major concern.
- Seeking **grants or financing programs** for aircraft restoration to reduce out-of-pocket expenses legally.
Ultimately, **safety and compliance should always take precedence over cost savings** in aviation.
Details:
Four packages, approximately 12x14x24, 30 lb. These are disassembled, honed, new rings, etc. Will charge actual shipping cost via any service. These were fully IRAN by Poplar Grove in late 2025 for an engine install on a IO-360-A1A, but then the customer decided to swap engines.
0 hours IRAN, yellow tagged, ready to install. Cylinders are currently at Airworthy Aviation KSBM Sheboygan, WI. Narrow deck, angled valve. Rare Lycoming 05K21112 Cylinders, quantity 4.
Fully to factory spec.
specifications engineaviatio:
- for models: Io-360, Io-720
- brand: Lycoming
- mpn: 05k21112
- part type: Cylinder Deck
shipping engineaviatio:
general engineaviatio:
- condition: Remanufactured
- Aviation Parts Accessories > Engines > Engine Components
offer engineaviatio:
- quantity: 1
- options: Ship-to-home
- sold: 0
- availability: In Stock
- started: February 13, 2026
seller engineaviatio:
- rating: 100.0%
- # reviews: 734
- city: Milwaukee, Wisconsin
returns engineaviatio:
- policy: No Returns
payments engineaviatio:
- other
- credit card: Mastercard
- wallet: Apple-pay
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