CMI Dimpled Billet Alt/Gen Power Pulley Kit 3.25" | Air-Cooled VW Type 1 | Black, Red or Blue | Made in USA
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The top half of CMI's power-pulley system. The CMI Precision Machining 3.25" Dimpled Billet Alt/Gen Power Pulley Kit is CNC machined in the USA from premium 6061-T651 billet aluminum, with a 7075-T651 aluminum pulley nut and a distinctive dimpled face. CMI machines it with the correct backspacing so it will not rub the alternator, and uses its unique, worry-free Posi-Lock machined pulley-half design. The kit includes the pulley nut and spacer plus four 0.015" steel shims.
Washburn's Metal is an authorized CMI Precision Machining dealer — genuine CMI parts, made in the USA, with full factory support.
Cooling caution (from CMI): 3.25" alt/gen power pulleys are intended to be used with 5.25" crank power pulleys to maintain adequate cooling fan speed. Do not install this pulley without also running a 5.25" crank power pulley.
Vehicle Fitment
- Air-cooled VW Type 1 engines with alternator or generator: Beetle, Karmann Ghia, Type 1-powered Bus, Thing, Baja Bug, dune buggies and sand rails.
- Must be paired with a 5.25" crank power pulley, such as the CMI 5.25" Billet Crank Power Pulley Kit.
- Not for Type 3 or Type 4 engines.
Key Features
- CNC machined in the USA from 6061-T651 billet aluminum (pulley halves / clamp)
- 7075-T651 aluminum pulley nut
- Dimpled billet face styling
- Correct backspacing so it will not rub the alternator
- Unique worry-free Posi-Lock machined pulley-half design
- Anodized in black, red or blue
What's Included
- Billet power pulley (two halves)
- Pulley nut and spacer
- 4 steel shims, 0.015"
Specifications
| Brand | CMI Precision Machining (Corona, CA) |
|---|---|
| Diameter | 3.25 in |
| Pulley / clamp material | 6061-T651 billet aluminum |
| Nut material | 7075-T651 aluminum |
| Finish | Anodized: Black, Red or Blue |
| Pairs with | 5.25" crank power pulley (required for adequate fan speed) |
| Country of origin | USA |
Part Numbers
| Color | Part # |
|---|---|
| Black | 2115 |
| Red | 2519 |
| Blue | 2520 |
Which Pulley Do I Need?
- Running a 5.25" crank power pulley? This 3.25" is the matching alt/gen pulley. Pulley ratio (calculated from diameters): about 1.62:1, versus about 1.57:1 for a 6.75" crank with a 4.3" alt/gen pulley.
- Running a full-diameter crank pulley such as CMI's 6.75"? Choose the CMI 4.3" Billet Alt/Gen Pulley Kit instead. A 3.25" top pulley with a 6.75" crank would spin the fan and alternator considerably faster (about 2.08:1).
- Color: black, red or blue anodized, all the same price.
Installation Notes
- Set belt tension with the supplied shims between the pulley halves; fewer shims between the halves tightens the belt. Store spare shims under the nut.
- A smaller pulley pair changes belt length requirements; confirm belt fit before final assembly.
- Follow the factory manual for pulley nut procedure and belt deflection.
FAQ
Can I use this with a full-diameter crank pulley?
CMI states 3.25" alt/gen power pulleys are intended to be used with 5.25" crank power pulleys to maintain adequate cooling fan speed. With a full-diameter crank pulley such as CMI's 6.75", choose the 4.3" pulley.
Does it fit both alternator and generator?
Yes, it is sold as an alt/gen pulley kit for the Type 1 engine.
What's included?
The pulley, nut and spacer, and four 0.015" steel shims.
Will it rub my alternator?
CMI machines it with the correct backspacing so it will not rub the alternator.
Is there a price difference between colors?
No.
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.