21641665 Idler Gear | Genuine Volvo Penta Part

🔧 Product Description

Timing-drive idler gear used in the D4 and D6 marine diesel chain-drive system. The gear guides and tensions the timing chain between the crankshaft, camshaft and injection-system drive components while maintaining accurate valve and injection timing.

🚤 Compatibility

• Engine Family: D
• HP Range: 145-480 HP

Full model list at the end of this description.

⚙️ Key Features

• Genuine Volvo Penta timing-drive gear
• Used with drive chain 3582642
• Works with hub 21165762 and bushing 3581885
• Related sprocket reference 3888601
• Included in applicable timing-chain service kits
• Engine type: Inline-four D4 or inline-six D6 common-rail marine diesel

🔌 Function

Guides the timing chain and preserves the correct relationship between the crankshaft, camshaft and fuel-system drive.

⚠️ Common Signs of Failure

• Timing-chain rattle
• Abnormal gear or chain wear
• Metal debris in the timing housing
• Excessive backlash or damaged teeth
• Timing correlation faults or difficult starting

🛠️ Service Notes

• Inspect the gear teeth, the bearing or bushing and the shaft or hub it runs on together — a new gear on a worn shaft will be noisy and short-lived
• Check the mating gears at the same time; a chipped or pitted tooth on either side will damage the new idler
• Where the gear forms part of a timed drive, set it up to the timing marks and the procedure in the workshop manual for your engine and confirm timing before turning the engine over
• Measure backlash and endfloat by the method in the manual rather than judging them by feel, and fit any thrust washer or plate in its original order and direction
• Oil the bearing surfaces and teeth on assembly and turn the drive over by hand to check it runs free before the covers go back on

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 21641665 → Supersedes 3582647

OEM / Related Numbers

• 3582647 earlier number superseded by this part

Other-Brand OEM Numbers

• VOE21641665

Aftermarket / Verified Equivalents

• Drive chain: 3582642
• Hub: 21165762
• Bushing: 3581885
• Sprocket: 3888601
• Timing-chain kits: 23594924 and 23594927

📦 Condition

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

🔎 Full Model Compatibility

Typically suits:

• Volvo Penta D6-330A-F, D6-370A-F, D6-330D-F, D6-370D-F, D6-300A-F, D6-300D-F, D6-300I-F, D6-340I-G, D6-380I-G, D6-440I-G, D6-480I-G, D6-300A-G, D6-340A-G, D6-380A-G, D6-440I-WJ-G, D6-480I-WJ-G, D6-300D-G, D6-340D-G, D6-380D-G, D6-440D-G, D6-480D-G, D6-400A-G, D6-440A-G, D6-300I-G, D6-330I-F, D6-370I-F, D6-435D-F, D6-400A-F, D6-435I-F
• Volvo Penta D4-260A-F, D4-260D-F, D4-260I-F, D4-300A-F, D4-300D-F, D4-180I-F, D4-225I-F, D4-300I-F, D4-225A-F, D4-175I-G, D4-230I-G, D4-270I-G, D4-320I-G, D4-300I-G, D4-150A-G, D4-230A-G, D4-270A-G, D4-320A-G, D4-300A-G, D4-145I-G