1556939 Piston Pin | Genuine Volvo Penta Part

🔧 Product Description

This genuine Volvo Penta piston pin is a precision piston-to-connecting-rod joint component used in the piston and connecting-rod assembly. It is manufactured to the original Volvo Penta dimensions and interface requirements so the piston and connecting rod remain accurately joined with the specified running clearance. 115 mm piston pin; also supplied in conversion kit 3826321. In service, it connects the piston to the connecting rod while allowing the piston to articulate through the stroke. Fitment is controlled by the exact engine or product configuration and serialised parts list; confirm OEM number 1556939 against the installed assembly before ordering.

🚤 Compatibility

Typically suits:

• Volvo Penta TWD1630G
• Volvo Penta TWD1630V
• Volvo Penta TD164KAE
• Volvo Penta TAMD162C-C
• Volvo Penta TAD1630G
• Volvo Penta TAD1630GE
• Volvo Penta TAD1630P
• Volvo Penta TAD1631GE
• Volvo Penta TAMD163A-A
• Volvo Penta TAMD163P-A
• Volvo Penta TAMD165A
• Volvo Penta TAMD165C
• Volvo Penta TAMD165P
• Volvo Penta TAD1631G

• Engine Family: TWD, TD, TAMD, TAD

⚙️ Key Features

• OEM Volvo Penta part number 1556939
• System group: Engine
• Net weight: 2.084 kg
• Supersedes previous part number 1556401
• Fits 16-litre TWD1630, TAD1630/1631, TD164 and TAMD162/163/165 series engines
• L=115mm (Volvo assembly listing)
• 6 used per assembly

🔌 Function

The piston pin forms the pivoting joint between the piston and the connecting rod small end, transferring combustion force from the piston crown into the rod. It must carry high cyclic loads while allowing the rod to swing freely through each stroke.

⚠️ Common Signs of Failure

• Knocking or rattling from the upper engine that is loudest at light load or idle
• Visible scoring, ovality or wear steps on the pin surface
• Excessive clearance or play felt between piston bosses and the rod small end
• Elevated oil consumption or blow-by linked to piston misalignment
• Discolouration or heat marking indicating loss of lubrication

🛠️ Service Notes

• Measure before assembling: pin, piston bore and rod bush must all be checked against the wear limits in the workshop manual for your engine, and a pin that has picked up or lost its finish is scrap
• Assemble spotlessly clean and generously oiled with clean engine oil or the specified assembly lubricant; a dry pin galls on the first turn of the engine
• Confirm piston and rod are the correct way round and correctly paired before the pin goes in
• Where the manual specifies a warm fit, warm the piston evenly by the method it sets out and push the pin home in one movement — never drive a pin in with a hammer
• Fit new circlips or retaining rings, compress them no more than needed to enter the bore, seat them squarely in the groove, and check each is fully home and cannot be rotated by finger pressure

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 1556939 → Supersedes 1556401

OEM / Related Numbers

• 1556401 earlier number superseded by this part
• 3826321 related reference

📦 Condition

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