• Adjustable camshaft pulleys for Alfa Romeo 33 1.7 16v Boxer (1990–1994), made of light alloy with surface hardening treatment on the teeth, offering at the same time a fantastic and distinctive engine bay look.
• Adjustable cam pulleys are essential when the engine has undergone machining such as decking/skim of the engine block or cylinder heads, very common operations in performance builds and overhauled engines. After skimming and removing material from heads or block, the valve timing geometry changes, causing: unintentional timing advance, altered valve overlap, loss of engine efficiency, drop in performance or suboptimal operation.
• Thanks to the micrometric adjustment on ProtoXide adjustable pulleys—and this engine has 4 pulleys—it is possible to restore the original timing after skimming and thus precisely compensate for the geometric variation while avoiding phasing errors that can compromise the engine and the optimization of valve overlap and opening.
• This makes it easy to recover lost power and torque, with maximum precision in timing setup.
• Moreover, with these pulleys you can adjust intake and exhaust independently and adapt timing to any machining performed, achieving professional, tailor-made tuning.
• Especially on Alfa Romeo 16V Boxer engines, even minimal skimming can significantly affect timing, and without adjustable pulleys, the valve timing remains out of phase and performance is not optimized.
• As a general rule, 0.10 mm of skimming becomes 1° of cam timing variation (indicative value), therefore 2° of crankshaft timing. Typical skims (0.3–0.5 mm) become up to 3°–5° of actual cam advance. On 16V engines like the Alfa Boxer these variations are very sensitive and directly affect volumetric efficiency.

Technical details of the pulleys:

• Cam bore/keyway: with key
• Outer diameter:
• Number of teeth:
• Tooth width:
• Number of pulleys per engine: 4, The price refers to the pulley set consisting of 4 pulleys for one engine.
• The 4 pulleys are built "almost" as if one pulley were the reverse of the other, so pay attention—the differences can also be seen in our photos—since they are not 2 identical pulleys, but each one differs from the other.
• The anodized color cannot be chosen and depends on availability at the time, between gold and red as in the photos, but the anodization usually supplied is the red one shown in the picture.