Billet machined steel hub with larger tabs. For use with stock oil pump disk.
VAC's solution for this very common S54 defect is a new camshaft hub manufactured from 4340HT Billet Bar and then heat treated to the BMW OE Rockwell Hardness spec. The VAC hub uses tabs that reduce the clearance from 1mm down to 0.2mm. The VAC VANOS Hub is a direct replacement for the original and does not require you to purchase a modified oil pump disk. This upgraded design is not only significantly stronger, but the larger diameter pins minimize the huge clearance to greatly reduce or eliminate at least one S54 VANOS problem. A 5-year warranty is included.
The tabs on the exhaust cam hub drive the oil pump for the S54 VANOS unit act like pins that get inserted into a disc on the back of the VANOS unit. Unfortunately, the holes on the disc are too large which leads the tabs to vibrate inside the holes and eventually crack and break off. Broken exhaust hub tabs on the S54 will cause the VANOS to stop working and if one of the broken tabs ends up in the valvetrain, timing chain, or the oil pump chain, it could be game over for your engine.The BimmerWorld View: you might have noticed we offer three unique solutions to this inherent S54 problem. Which is the best? We don't really have a Good, Better, Best recommendation here. These are three different approaches with the same result - a more robust and reliable S54 exhaust hub. Your decision may come down to what else you will be changing - the Beisan and Dr Vanos solutions can be used with a stock disk but we urge you to use a modified one. The VAC will only fit with a stock disk. Plan accordingly but you really can't lose with any one of these.
E46 (99-05) > M3
E36/7 / E36/8 Z3 (96-02) > Z3 M - S54
E85 / E86 Z4 (03-08) > Z4 M