20859646 Compression Spring | Genuine Volvo Penta Part

🔧 Product Description

A genuine Volvo Penta exhaust-valve spring for the D5/D7 cylinder head. The spring is manufactured to the specified free length, coil geometry and load curve required to close the exhaust valve positively against combustion pressure while following the cam profile throughout the engine speed range.

🚤 Compatibility

Typically suits:

• Volvo Penta TAD560VE
• Volvo Penta TAD561VE
• Volvo Penta TAD734GE
• Volvo Penta TAD752GE
• Volvo Penta TAD753GE
• Volvo Penta TAD754GE
• Volvo Penta TAD765VE
• Volvo Penta TAD764VE
• Volvo Penta TAD763VE
• Volvo Penta TAD762VE
• Volvo Penta TAD761VE

• Engine Family: TAD

⚙️ Key Features

• Genuine Volvo Penta Exhaust Valve Compression Spring - part number 20859646
• Engine-specific exhaust-valve spring for the Volvo Penta cylinder head
• Calibrated spring rate and installed load maintain valve-to-cam contact
• Controls the heavier thermal and pressure duty of the exhaust valve
• Resists surge, coil resonance and loss of control at governed engine speed
• Must be checked with the correct retainers, valve, guide and installed height
• Replace any spring that is cracked, heat-discoloured, out of square or below the service-load specification
• Engine type: D5/D7-series industrial and generator diesel cylinder heads

🔌 Function

The spring returns the exhaust valve to its seat after the rocker arm releases it and keeps the valve train in continuous contact with the camshaft. Correct spring force is essential for compression sealing, valve timing and preventing valve float or contact between moving valve-train components.

⚠️ Common Signs of Failure

• Exhaust valve does not close fully or compression is reduced
• Valve-train clatter, misfire or loss of power at higher speed
• Broken coil or visible heat discolouration
• Free length or spring load below service specification
• Valve float leading to rocker, valve or piston damage

🛠️ Service Notes

• Compare the new spring with the one removed for free length and coil condition; a spring that has taken a set or lost length is past its useful life
• Look over the old spring for corrosion pitting, bright rub marks and cracked or broken coil ends, and check whatever it bears against for the same wear
• Never stretch, shorten, grind or heat a spring to alter how it behaves — fit the correct part instead
• Seat the spring squarely in its recess or over its guide with the ends fully home, so it cannot cock over or bind in service
• Where springs work as a group, renew them together so the load stays even across the set

🔄 Supersession & Cross Reference

Other-Brand OEM Numbers

• VOE20859646

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging