21663840 Shim | Genuine Volvo Penta Part

🔧 Product Description

Genuine Volvo Penta D6 and D7 Cylinder-Liner Spacer-Ring Shim, selective service thickness - Part Number: 21663840 A selective spacer-ring shim used during D6 and D7 cylinder-liner service to establish the specified liner protrusion above the cylinder-block deck.

⚙️ Key Features

• Nominal selection: selective service thickness
• Cylinder-liner protrusion adjustment
• Precision-ground hardened steel
• Selected only after liner-height measurement
• Used during cylinder-block and liner repair

🔌 Function

The shim raises the cylinder liner by a controlled amount so the head gasket is clamped correctly and combustion pressure remains sealed.

⚠️ Common Signs of Failure

• Incorrect liner protrusion
• Repeated cylinder-head gasket failure
• Coolant pressurisation
• Shim compressed, corroded or damaged during removal

🛠️ Service Notes

• Shims are supplied in graded thicknesses and exist to bring a setting into specification, so measure with a micrometer and select the thickness the setting procedure for your engine calls for rather than matching one by eye
• Note which shim came from which position on removal and keep them identified — once an assembly has bedded in, shims are not interchangeable between positions
• Check both faces are clean, flat and free of burrs, corrosion and old sealant before fitting; dirt trapped under a shim shifts the setting as surely as the wrong thickness does
• Discard any shim that is dished, cracked, pitted or fretted rather than reusing it, and make sure no old shim has been left behind in the recess
• Recheck the clearance or setting after the assembly is tightened down, because clamping load can change the measurement you took loose

🔄 Supersession & Cross Reference

OEM / Related Numbers

• 21663836-21663840 - Selective spacer-ring shim family

📦 Condition

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