CMI Billet Crank Power Pulley Kit 5.25" | Air-Cooled VW Type 1 | 6 or 12 Spoke, Stock or Sand Seal Hub | Black, Red or Blue | Made in USA

CMI's reduced-diameter power pulley, in the same billet quality as its stock-size crank pulley. The CMI Precision Machining 5.25" Billet Crank Pulley Kit is the "power pulley" in CMI's lineup, CNC machined in the USA from premium 6061-T651 billet aluminum with the CMI logo and timing marks engraved directly into the face. It is built on a heat-treated 4140 steel hub with a black zinc finish, fastened with six stainless steel flat-head cap screws, and the back is pre-drilled and tapped for CMI's optional 5.25" Hall-sensor crank trigger wheel.

Washburn's Metal is an authorized CMI Precision Machining dealer — genuine CMI parts, made in the USA, with full factory support.

Important: CMI states that its 3.25" alt/gen power pulley is intended to be used with the 5.25" crank power pulley to maintain adequate cooling fan speed. Plan to run the pair together (see the sizing guide below).

Vehicle Fitment

• Air-cooled VW Type 1 engines in Beetle, Karmann Ghia, Type 1-powered Bus, Thing, Baja Bug, dune buggies and sand rails.
• Not for Type 3 or Type 4 engines.
• Sand Seal hub versions are only for cases machined for a sand seal; choose Stock hub for a standard case.

Key Features

• CNC machined in the USA from 6061-T651 billet aluminum
• Anodized: hard black anodized, or red or blue anodized (stock-hub versions)
• Heat-treated 4140 steel hub, black zinc plated, six stainless flat-head cap screws
• CMI logo and timing marks engraved into the pulley
• Pre-drilled and tapped for the CMI 5.25" Crank Trigger Wheel Kit (Hall sensor, 36-1), sold separately
• 6-spoke or 12-spoke design

Specifications

Part Numbers

Which Pulley Do I Need?

• 5.25" power pulley vs 6.75": the 5.25" crank turns the fan and alternator/generator more slowly for a given alternator/generator pulley size. CMI's guidance is to pair it with the CMI 3.25" Dimpled Billet Alt/Gen Power Pulley to maintain adequate cooling fan speed. If you want to keep a standard-size alternator/generator pulley, choose the CMI 6.75" crank pulley instead.
• Pulley ratios (calculated from diameters): 5.25" crank with 3.25" alt/gen = about 1.62:1; 6.75" crank with 4.3" alt/gen = about 1.57:1; 5.25" crank with 4.3" alt/gen = about 1.22:1, which slows the cooling fan noticeably. Ask us before mixing sizes.
• 6 vs 12 spokes: styling only; same materials, hub and price.
• Stock vs Sand Seal hub: Sand Seal only for a case machined for a sand seal (black only).
• EFI or crank-fire: add the CMI 5.25" Crank Trigger Wheel Kit (Hall sensor).

Installation Notes

• Replaces the factory crank pulley on the crankshaft snout using your crank pulley bolt and washer (CMI stainless bolt and washer kit A07 available separately).
• A smaller crank pulley changes belt geometry; confirm belt fit and tension, and shim the alt/gen pulley to set tension and alignment.
• Verify ignition timing against the engraved marks with a timing light after installation.
• Use the torque specification from your engine builder or factory manual for the crank pulley bolt.

FAQ

Do I need a smaller alternator/generator pulley with this?
CMI states the 3.25" alt/gen power pulley is intended to be used with the 5.25" crank power pulley to maintain adequate cooling fan speed.

Which hub should I choose?
Stock hub for a standard case; Sand Seal only if your case is machined for a sand seal (black only).

Is the crank trigger wheel included?
No. The pulley is pre-drilled and tapped for the CMI 5.25" Crank Trigger Wheel Kit, sold separately.

Will it fit a Type 3 or Type 4?
No, it is made for the Type 1 engine.

Are all colors the same price?
Yes.

Where is it made?
CNC machined in the USA by CMI Precision Machining.

Are you an authorized CMI dealer?
Yes. Washburn's Metal is an authorized dealer for CMI Precision Machining, so you get genuine CMI parts and factory support.