20411979 Valve Seat | Genuine Volvo Penta Part

🔧 Product Description

Genuine Volvo Penta 0.20 mm oversize exhaust-valve seat for selected TAD1240GE, TAD1241GE and TAD1242GE cylinder heads. It is used only after the cylinder-head seat bore has been professionally machined to the matching repair dimension.

🚤 Compatibility

Typically suits:

• Volvo Penta TWD1240VE
• Volvo Penta TAD1241GE
• Volvo Penta TAD1242GE
• Volvo Penta TAD1240GE

• Engine Family: TWD, TAD

⚙️ Key Features

• Hardened exhaust-valve seat in 0.20 mm oversize
• Twelve seats used in the applicable six-cylinder head
• For repair of an enlarged or damaged exhaust-seat bore
• Requires controlled interference-fit installation and final seat cutting
• Must be matched to the cylinder-head serial break and valve-seat family
• Engine type: Volvo Penta 12-litre six-cylinder industrial diesel

🔌 Function

Provides the hardened sealing and heat-transfer surface for the exhaust valve after an oversize seat-bore repair.

⚠️ Common Signs of Failure

• Loss of compression at the exhaust valve
• Valve-seat recession or cracking
• Poor valve contact pattern
• Seat loose in the cylinder head
• Cylinder-head bore outside the standard repair dimension

🛠️ Service Notes

• Seat inserts are an interference fit in the head, so the counterbore has to be clean, round, flat and square before a new seat goes in; normal practice is to chill the insert and warm the head so it drops into place rather than forcing it
• This is machine-shop work — the seat must be cut concentric with the valve guide after installation, so check or renew the guides at the same time and cut the seat angles once the insert is secure
• Inspect the head casting for cracks and for a pounded or spread counterbore before committing to a new seat; a seat that has come loose has usually damaged its pocket
• Use the interference fit, insert size and seat angles specified for your engine rather than any general figure, as they differ between heads
• Check each valve on its finished seat for an even contact band right the way round, and confirm valve position and any permitted recession against the workshop manual for your engine

🔄 Supersession & Cross Reference

OEM / Related Numbers

• 3169366 - standard exhaust seat from SN 303404 onward
• 3165369 - earlier standard exhaust seat through SN 303403
• 20459329 - standard inlet valve seat
• 20459332 - related oversize inlet valve seat

📦 Condition

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