Overview
The ZF 4681.130.004 Engine Connection is a critical OEM genuine coupling component designed to link the engine flywheel housing directly to the bell housing of ZF marine and industrial transmissions. This precision-machined adapter plate ensures perfect axial alignment between the power source and the gearbox, preventing driveline vibration and premature bearing wear. As a factory-specification part, the 4681.130.004 maintains the exact dimensional tolerances required for sealed oil retention and structural rigidity under high-torque loads. It serves as the primary structural interface where engine output meets transmission input, making its integrity essential for reliable power transfer in both the BP 210 and BP 230 series configurations.
Symptoms of Failure
When the ZF 4681.130.004 Engine Connection begins to degrade, operators typically notice these specific failure indicators:
- Oil seepage at the engine-to-transmission mating surface – A worn or warped connection plate allows transmission fluid to escape past the gasket, often visible as dark drips beneath the bell housing area.
- Low-frequency driveline vibration during load changes – Misalignment caused by a fatigued connection results in a noticeable shudder when shifting from neutral to forward or reverse under moderate throttle.
- Gradual gear engagement delay or harsh shifting – As the connection loses its rigid hold, the transmission input shaft can shift minutely, causing inconsistent clutch pack pressure and delayed response.
- Metallic debris in the bell housing inspection port – Fretting wear between the connection plate and flywheel generates fine steel particles, indicating imminent structural failure of the mounting interface.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number / SKU | 4681.130.004 |
| Overall Diameter | 320 mm (12.6 in) |
| Thickness (Flange) | 18 mm (0.71 in) |
| Bolt Hole Pattern | 8 x M12 on 280 mm PCD |
| Material | EN-GJS-500-7 Ductile Cast Iron |
| Weight | 4.2 kg (9.3 lbs) |
| OEM Reference | ZF 4681.130.004 (Genuine) |
| Surface Finish | Ground flatness ≤ 0.05 mm |
Compatibility
This genuine ZF engine connection is engineered for direct fitment on the following transmission model families:
- BP 210 Series – All variants including BP 210, BP 210-1, and BP 210-2 with SAE 3 flywheel housings.
- BP 230 Series – Standard BP 230 and BP 230-1 configurations used in marine propulsion and industrial pump drives.
- WG 180 Series – Earlier WG 180 models where the bell housing pattern matches the 280 mm PCD bolt circle.
- WG 200 Series – Select WG 200 gearboxes with non-integral engine adapters requiring a separate connection plate.
Important: Always verify the flywheel housing SAE size and bolt pattern before installation. This part is not compatible with ZF 220A or 300 series transmissions without an additional adapter ring.
