plastic cam cogs - rebuilt

Forget about wasting your money on those expensive after-market aluminum cogs. If your cogs' teeth and hubs are still good but, the flanges are beat up, they can be rebuilt with aluminum flanges as I did with mine. See the attached pics...The result is a cog which is much better than the original ---and still retains the soft, "belt-friendly" plastic teeth plus the strength of the original steel hubs.
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Thanks for the kudos all ---

Yes, I did the design and fabrication myself. I work for an Aerospace company so I have the luxury of access to machining equipment. The costs were simply my time --- about 3 hours on the lathe, and materials --- about $50.

I chose to leave the flanges bare Aluminum 6061, but you could anodize them before assembly if you wished. Although the corrosion protection is not too important --- there is already a lot of bare Aluminum in the engine compartment!

The flanges are bonded to the cog bodies with an Aerospace adhesive similar to what Ferrari uses for its current Aluminum chassis designs --- the bond will outlive the life of the car!

If you look closely at the original cog design, you will notice that it is a 2-part assembly. The cog body is a fiberglass molded part (with a steel insert for the hub) and the flange is a flat, plastic D-ring glued to the body.

Verell, your assumptions are correct --- My design incorporates an L-section flange, which extends into the bore of the cog body ---- this gives much more strength and a larger area for bonding. The OD of the flange wall is cut slightly smaller than the ID of the bore in the cog body to give a clearance for the appropriate adhesive bond line thickness. A stepped land on the flange creates a line-to-line fit with the bore to provide precise centering. The small holes in the flanges are used to inject the adhesive --- the parts are assembled dry, then the adhesive is injected to fill the gap.

If there is enough interest out there, I am considering generating a CNC routine which would cut flanges and cogs much faster to reduce costs (cutting them manually took about 3 hours and would be expensive if you had a machine shop do the work), and perhaps providing re-furbished cogs to other folks. I’m not sure yet would the cost would be ---- but, a new set of aftermarket Aluminum cogs goes for around $1,000, and a set of good used cogs (virtually impossible to find) is around $800. I could certainly provide a set like mine much cheaper than that!