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critical VP44 installation information

VP44 Keyway Technical Service Bulletin

Key - At the end of the VP44 driveshaft you will find an offset, malleable aluminum woodruff “key". This key is used for two things, first it is used for positive timing of the pump to the engine and second is offset of the key for internal timing of the pump. Each key is stamped with its offset, and an arrow which should point to the pump for correct orientation.

Injection Pump Gear Keyway - The slot inside the injection pump gear that the key will slide into for correct timing.

Install - Having the injection pump gear keyway at the 12 o’clock position will help with reference of engine position and also to reduce the risk that if the keyway somehow becomes dislodged from the pump you will have less possibility of it falling into the crankcase. Once the key is properly engaged in the keyway, there will be less initial resistance installing the pump to the injection pump gear.

Visual Inspection - Because the injection pump has a tapered shaft, there will be a “press fit" of the pump to the gear. Because the aluminum key is soft and malleable, if the keyway is not aligned it will simply “crush" or “creel" without the installer knowing. This is why it is critical, CRITICAL that once you have the pump torqued to the gear completely that you remove the nut and lock washer and inspect the keyway again for proper alignment. The key will be farther in the keyway and will be much easier to see.

Miss Installed key Correct good key
Miss Installed key Correct good key.
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