CMB Valvola Mk1 drum rotor mods
PMB Model Boats
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To improve the performance of the Valvola engine, the drum rotor can be filled. Turn a piece of delrin to a diameter of 0.05mm bigger than the internal diameter of the rotor. Press it into the rotor and shape the internal part of the delrin to give a good flow for the induction gases. As you can see in the picture, the delrin can extend out of the drum by 1 to 1.4mm because there is a space between the end of the drum and the end of the rotor housing.
Dave Marles. 01/01/03