70310 - Lycoming™ OEM Shroud Tube Seal

70310 – Lycoming™ OEM Shroud Tube Seal

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Overview

The Lycoming 70310 is a genuine OEM shroud tube seal, a flight-critical component designed to prevent oil leaks from the base of the pushrod shroud tubes on a wide range of Lycoming engines. This is not a standard O-ring; it is a precision-molded seal, often referred to as a "packing," engineered to create a positive, durable seal between the aluminum pushrod tube and the engine crankcase. Manufactured from a high-temperature, oil-resistant synthetic rubber, the 70310 is essential for maintaining a clean, leak-free engine and ensuring proper oil containment.

Key Features

• Positive Oil Sealing: Its sole function is to create a tight, reliable seal at the base of the pushrod shroud tubes where they enter the engine crankcase. This prevents pressurized engine oil from leaking out, which is one of the most common sources of oil leaks on Lycoming engines.
• High-Temperature Synthetic Rubber: Fabricated from a specialized, high-grade synthetic rubber compound (often silicone). This material is chosen for its exceptional resistance to degradation from hot engine oil and its ability to maintain flexibility and sealing force across a wide range of operating temperatures.
  
• "Waffle" or Ribbed Design: Often features a ribbed or "waffle" pattern on its sealing surfaces. This design increases the surface area and provides multiple sealing lips, creating a more robust and reliable seal compared to a simple flat gasket.
• Compression Set Resistance: The material is formulated to resist "compression set"—the tendency of a rubber seal to permanently flatten over time when compressed. This ensures the seal maintains its outward pressure and sealing capability for its full service life.
• Genuine Lycoming OEM Part: As a genuine factory component, it guarantees the correct material composition, durometer (hardness), and dimensional tolerances required for a long-lasting, leak-free seal as specified by the engine's original designers.

Technical Specifications

• Part Number: 70310
• Component Type: Pushrod Shroud Tube Seal / Packing
• Material: High-Temperature, Oil-Resistant Synthetic Rubber (e.g., Silicone)
• Primary Function: Seals the base of the pushrod tube to the crankcase.
• Certification: FAA Production Approval

Aircraft Compatibility

The Lycoming 70310 is one of the most common seals in the general aviation piston fleet, used on a vast number of Lycoming's most popular 4- and 6-cylinder engines.

• Common Lycoming Engine Series:
  • O-235
  • O-320, IO-320
  • O-360, IO-360, AIO-360, AEIO-360
  • O-540, IO-540, TIO-540, AEIO-540
    
• Common Aircraft Platforms:
  • A vast range of aircraft from Piper, Cessna, Beechcraft, Mooney, and numerous experimental designs that utilize the above Lycoming engine series.

Applications

The 70310 is a critical component for engine maintenance and overhaul:

• Engine Overhaul: A mandatory replacement item during any engine overhaul or when the cylinders are removed. All pushrod tube seals are replaced to ensure a leak-free engine.
• Oil Leak Repair: The primary component to replace when troubleshooting oil leaks that appear to originate from the base of the cylinders.
• Preventative Maintenance: Worn, hardened, or cracked pushrod tube seals are a common finding during annual inspections and are replaced to prevent future leaks.

Why Choose 70310?

While a small oil leak from a pushrod tube may seem like a minor nuisance, it can coat the engine compartment in a flammable film of oil, obscure the view of other potential problems, and lead to significant oil loss over time. The Lycoming 70310 is the genuine, factory-specified seal designed to prevent this. Using a genuine OEM part ensures the seal is made from the correct, high-temperature material that will not prematurely harden or shrink. For a clean and reliable engine, there is no substitute for genuine Lycoming seals.

Website Metadata

• Meta Title: 70310 Lycoming Pushrod Shroud Tube Seal | OEM | Airparts.aero
• Meta Description: Purchase the genuine Lycoming 70310 pushrod shroud tube seal. A flight-critical, high-temperature rubber packing for preventing oil leaks on Lycoming O-320, O-360, and O-540 series engines.
  
• SEO and Plain Text Keywords: 70310, Lycoming parts, pushrod tube seal, shroud tube seal, engine gasket, Lycoming seal, O-360 parts, IO-540 parts, aircraft engine parts, oil leak, OEM Lycoming parts, Airparts.aero.

Order Your Lycoming 70310 Seals Now

Ensure a clean, leak-free engine with genuine, factory-certified Lycoming seals. Visit Airparts.aero to order your 70310 pushrod tube seals today.

SEO-Enhanced Addendum

The 70310 seal is a critical static seal in the engine's lubrication system. The pushrod shroud tubes provide a protected pathway for the pushrods to travel from the camshaft/lifters in the crankcase up to the rocker arms in the cylinder head. More importantly, these tubes serve as the return path for the oil that has lubricated the valve train in the cylinder head to drain back into the oil sump. The 70310 seal is what prevents this returning oil from leaking out at the junction of the tube and the crankcase. The seal is held in place by a spring-loaded retainer system that maintains a constant compression on the seal, ensuring it remains effective even as the engine's cylinders expand and contract with temperature changes.

Note: This is a flight-critical engine component. Installation must be performed by a certified A&P mechanic in strict accordance with the current Lycoming Overhaul Manual and relevant Service Instructions. All sealing surfaces must be meticulously clean before installation.

Description: Shroud Tube Seal 
Part Number: 70310
FAA Eligibility [ Click Here ]
Alternate Part Numbers: AEL70310, SL70310, STD-1291, 69523, 62922, 60053, AL70310

Product Overview

A nonmetallic circular item with an aperture, having a solid round cross-section. They are used primarily for sealing. For items with other than round cross-section, see packing, preformed. For noncircular items with a round cross-section, see seal, nonmetallic round section, and rubber, round section.

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