How To make Cams for Four-stroke Engines

Created: Feb, 2009
Last updated: October, 2009
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An accurately machined camshaft is essential to the successful operation of a model four-stroke engine, or a full-size one, come to think of it. I'm sure many would-be model engine builders have seen photos of the complicated Heath-Robinson like cam grinding machines that appear in the model engineering press from time to time and concluded that while they might like to have a go at a four-stroke, they don't have the time required to build a cam grinder, or the expense would be too great, or they don't have the space to store the dam thing between infrequent uses (I sympathize with the latter case ). Well, Fred, there are other ways of making your cam than by grinding it.

Turns out (pun), there are lots of alternatives when it comes to making cams. Harmonic Cams formed by grinding from a much magnified master cam profile are as good as you can get, but our hobby abounds with many very successful model engine where the cam profile has been formed by far less sophisticated methods. For instance, the Whittle Aero V-8 is about as complex as you can get and I've seen several running away happily with cams that have flat flanks and a hand filed nose radius. This Hot-To page serves as a place to collect the references on this site to ways of making cams and will grow over time. Follow the links below to read the details.

Milled cams attached to shaft (Feeney 15cc)
Milled one-piece camshaft (Cirrus in-line 4)
Offset turned one-piece camshaft (PeeWee V4)
Cam Making Made Easy (Seagull SV Twin)
Cam Grinding Machines



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